Manufactured Home Plumbing: Drainage and Ventilation Issues

 

Learn how to diagnose and repair poor drainage and other ventilation issues in your home’s plumbing system. Issues such as foul odor, gurgling, and slow drainage may be repaired quickly and easily!

 

Since plumbers are expensive it pays to learn how to fix plumbing issues yourself. At the very least, understanding more about your home’s plumbing system can help you save money when hiring a professional.

Learn more about manufactured home plumbing with our article Plumbing In Manufactured Homes: The Basics.

Note: Your state and local plumbing codes will determine the exact requirements that your manufactured home must meet when it comes to plumbing (and electricity, additions, foundations, decking, roofing…basically everything). While HUD sets standard manufactured home building codes on a national level, your state and local laws will take precedence. 

Manufactured Home Vs. Site-Built Home Plumbing

There are a few differences between manufactured home and site-built home plumbing systems.

Plumbing pipes, or lines, are typically placed under a manufactured home and stubbed up through the floor while site-built homes usually have their pipes placed inside the walls. Getting to the pipes is much easier in a manufactured home. The drawback is that pipes ran under a mobile home are more prone to freezing but that issue can be easily fixed.

Manufactured homes typically do not have clean-outs or overflows like a site-built home. The lack of clean-outs can be troublesome when tackling trunk line blockages (technically this is not a ‘mobile home’ issue, but more of a property preparation issue).

Manufactured homes have played an important aspect in the evolution of modern plumbing. New products are often installed on factory-built homes long before they make it to the traditional housing market. PEX, a now favorite product of plumbers worldwide, was first tested and used in manufactured homes.

The 3 Basic Elements of a Plumbing System 

All home plumbing systems, whether in a manufactured or site-built home, have three main elements: supply lines, drainage lines, and ventilation.

Your supply lines are completely separate from your drainage and ventilation but your drainage lines and ventilation are typically together. All three of these elements work together – if one part of the system is broken the entire system is broken.

This video from Home Dept explains how a basic plumbing system works:

Supply Lines

Supply lines carries water into and throughout your home.

Leaks around connections will be your biggest concern with supply lines. Frozen water lines is another big problem that manufactured homeowners face. You can learn how to repair both issues on our manufactured home plumbing basics article. 

Drainage and Ventilation Lines 

Drainage lines carry waste water out and away from your home. We explained drainage in our first plumbing article, Plumbing in Manufactured Homes; The Basics:

Drainage lines use gravity, traps and ventilation to ensure the optimum waste removal and keep gases and fumes from building up and releasing. Think of this as a completely closed system with positive and negative vacuum or pressure. All the parts have to work correctly to allow the system to do what it is designed for. Without the proper positive or negative pressure acting as a vacuum in the pipes the waste won’t go where it’s supposed to, it can back-flow instead.

Diagnosing Poor Drainage and Ventilation Issues

There are a few signs that will clue you into drainage or ventilation issues.

Signs of Poorly Vented Plumbing Drain Lines:

  • Slow Drainage
    • Slow waste water drainage is one of the first signs of a ventilation issues.

 

  • Gurgling
    • If you hear gurgling come from your drains you likely have poor drainage caused by ventilation issues.

 

  • Foul Odors
    • Foul odor can be another sign of poor drainage or ventilation issues.

Water Heater Odors

Note: Not all foul odors are caused by venting problems. Foul water odor could be coming from your water heater.

  • Missing Water in your Toilet
    • Nope, the dog probably isn’t drinking all the toilet water! (Source) If you find your toilet is missing its water you may have either a drainage leak or a ventilation problem.

 

  • Air Bubbles in Your Toilet Water
    • Seeing or hearing bubbles rise from the toilet bowl is another sign that your drainage system isn’t getting enough ventilation.

All of these issues can be caused when your drainage system is air-locked or when the p-traps are emptied of their water due to poor ventilation. Learn more about drainage noises here. 

If your drain lines leak you’ll probably be able to tell. Water or dampness under your home is a big clue but foul odors and soggy ground can also be signs. Repairing a drainage line leak is fairly straight forward – you find the issue and replace that area. However,  if you have determined there is no leak but you are still incurring issues described above you likely have a ventilation problem.

Venting Your Drainage Lines

A healthy plumbing system must be able to breath.

Think of a drain system as having two elements within the same pipe. The lower part of the pipe is where the waste water goes and the upper part is how the ventilation enters to provide the lower drain lines with proper (neutral) air pressure.

A two liter bottle may help explain this better:

When pouring soda out of a plastic 2 liter bottle you can see just how important ventilation can be. Turn the bottle completely up, where no air can enter the through opening, and the soda gurgles and slows. If you don’t turn the bottle completely up and allow air to enter the soda comes out faster and more smoothly. That’s exactly what proper ventilation does for you drain lines.

Inspectapedia.com explains the functions of plumbing vents well:

How do Plumbing Vents Work & Why Are they Needed

The venting system equalizes the air pressure throughout the waste piping system. Why does this matter? Let’s look at four functions of vents.

1. The waste won’t flow properly if it can’t push the air in the pipe ahead of the waste out of the way. Plumbing vents allow air out of the waste pipes.

2. The waste won’t flow well if it’s held back by low air pressure or a vacuum in the pipe behind it. Vents allow air into the waste pipes.

3. We don’t want the water to be siphoned out of the trap every time a fixture is used. It’s the water sitting in a plumbing trap that stops sewer gases getting into the home. Vents allow air in to prevent a siphon.

4. Plumbing vents allow sewer odors to escape from the house, venting safely above the roof. Without venting, the sewer gases seep through the water in the trap and enter the house. Vents help sewer gases escape outdoors.

Allow building drains to flow freely by allowing air into the drain system, avoiding the vacuum and slow drainage that would otherwise occur at fixtures.

Allow sewer gases to be vented safely outdoors. Because sewer gases may flow back up into the building drain piping from a public sewer or private septic system, and because some sewer gases are included in building waste flowing through the piping, the plumbing vent system needs to carry these gases outside, usually above the building roof, where they are disposed-of safely and without leaving unpleasant, or possibly dangerous smells and gases inside the building.

Ventilation can be achieved in two ways: through proper use of vent stacks and through auto vents. In cases where a pipe can’t have its own venting, plumbers use a product called an auto vent, or air admittance valve.

Plumbing, Drainage, and Ventilation Terms

Plumbers, like all construction workers, speak a different language from the rest of the world.  Living with a master plumber for 18 years has given me just enough time to learn some of their language (not all of it by any means). Here are some of the more common plumbing words and their meaning:

Wet Vents

Wet vents are a drain system where one pipe serves as a vent for one fixture and a drain for another (source) or a waste pipe that also serves as a vent pipe (source).

Wet vents can consist of a toilet and sink (left image below) or a toilet, sink, and tub (right image below). It could also be the kitchen sink and the laundry sink, whichever is closest. Here’s how HomeTips.com explain wet vents:

With wet venting, fixtures that are relatively close to the soil stack (the main vertical drain-waste-vent pipe) are connected directly to it, even if the section of stack above the connection serves as a drain for another fixture.

wet vent example - toilet and sink
wet vent example - toilet- sink-tub

Stack Vents

A vent stack is the small pipe that you see coming out of your roof. It completes the wet vent system.

Regular Checkups of your Vent Stack 

Vent stacks can get clogged by leaves, birds, rodents, and countless other things. They can also settle, either due to poor installation or accidental cutting. Luckily, you can buy toppers that allow good air flow but keeps things from falling into the pipes. Vents can also get crushed or bent so a regular checkup is recommended to ensure there are no leaks around the seal and that nothing is blocking air flow.

 

repairing a plumbing vent stack

Inspectapedia.com has a couple of great pages about stack repair:

Plumbing Vent Repair 

Plumbing Vent Code Problems

 

 

Air Admittance Valves

You’ve likely never noticed an air admittance valve, or auto vent as some call it, under your sinks or inside your walls. Even if you have seen them, you probably didn’t realize how important it was to your home’s plumbing system. They are handy little things!

An air admittance valve is used in cases where connecting a drain pipe to a stack vent is difficult or impossible. They ensure that waste goes down to the sewer and gases stay out of your home.

Look under your sinks and see if you see something like this (it could be black or white, straight or domed):

 Cheap air admittance valves

 

How do Air Admittance Valves Work?

DIYAdvice.com explains AAV’s best:

Air admittance valves are operated by gravity. When water and waste move down a drain line, it creates negative air pressure in the pipe. This negative pressure lifts the sealing washer and lets air in, which allows the waste to drain away freely. When the negative pressure ceases, the sealing washer falls back in place. Earlier versions of this device were spring-operated. Such units are still available but are not reliable and don’t meet code in most places.

how an air admittance valve works

Essentially, an air admittance valve acts like a set of lungs for a weakly ventilated drainage system. It allows the pipe to suck in air when needed and yet closes off when it’s not needed.

installing an air admittance valve under a sink

 

 

 

Studor Air Admittance Valves

Studor is most plumber’s favorite brand for auto vents, or air admittance valves. Joe, the master plumber of the family, always recommends that homeowners replace their original manufactured home’s generic air admittance valve with a Studor brand as soon as you notice signs of failure. These valves do fail and there is a huge difference between a $5 item and a $35 item.

(Note: Studor does not pay us for this recommendation. After 18 years as a master plumber you tend to learn what works and what doesn’t.)

This video from Studor explains how their air admittance valves work:

 

How to Install an Air Admittance Valve Under Your Sink

If you notice any of the above signs of drainage or ventilation issues you may want to install or replace an air admittance valve.  DIYAdvice uses the following images and descriptions in their step-by-step guide on how to install an air admittance valve under a sink:

 installing an AAV onto a drain pipe - step 1

Step 1

Install the PVC drain line, the sanitary tee, and the P-trap for sink. The appropriate coupling for the AAV (glued or threaded) attaches to the tee. Check the manufacturer’s instructions and local codes to determine the proper height for the AAV above the drain (source).

installing an AAV onto a drain pipe - step 2

Step 2

Depending on the type of fitting, glue or screw the AAV in place.

installing an AAV onto a drain pipe - step 3

Step 3

Depending on local codes and the AAV model, the completed installation should look something like this (source).

Other Drain Pipe Questions and Answers

Question 1:

I live in a 1987 mobile home. When the washer drains, water will back up into the kitchen sink and the fumes are horrible. Sometimes the water even overflows from the drain onto the laundry room floor. I see no vent stack thru the roof nor do I see any under sink venting devices. What do you suggest to correct this problem?

 

Answer: You are experiencing a very common issue in manufactured homes. It’s kind of a double whammy of not enough (or failed) ventilation and possibly too small of a drain line from the washer.

First, try adding a Studor auto vent under the kitchen sink. That should help the smell. Studor is the best name brand and well worth spending the extra money over the other auto vents.

If your washer drain line is only an inch and a half pipe you may want to consider re-piping it with a two inch pipe. While doing that, tie it in under the house directly to the main drain/trunk line itself, separate from the kitchen drain. That will definitely fix your problem! Those 1.5″ pipes just aren’t meant to handle a lot of water, especially high pressure water being released from a newer washer.

Try the auto vent first, especially if there is no stack connected to the immediate system (though there could be one in the walls that has failed – the cheaper vents seem to fail after only a few years).

 

 

Question 2:

I have a 1981 Hallmark 2 bedroom trailer. Our bathroom and kitchen sink won’t drain. The tub and toilet are fine. I’ve taken apart the plumbing under the sinks, and ran a snake as far as i could, and still nothing. I’ve crawled all under the trailer, and the only lines I see coming down and connecting to the waste/septic is for the washer (also fine). The trailer is insulated very well underneath, and i’ve cut a couple spots looking for pipes under the sinks but for the life of me I can’t find anything lol. I’ve even googled various phrases relating to the plumbing plan, to no avail. Any ideas?

 

Answer: Its most likely a blockage or ventilation issues. Try a true professional plumber’s snake (those they sell at Lowe’s or Home Depot are not that great and are mostly for sinks, not drainage line blockages. You should be able to rent one. Poor ventilation could be air locking the system as well. Those are the most likely issues.

 

 

 

 Question 3: 

I have running water, but I have this horrible stench in the kitchen and it sounds like scratching in my walls first it was on the repair side of the house now alternate on both sides. The odor became so bad 4 days after we had water we left the house after raising 5 windows in the house. I returned the odor comes and goes and I haven’t heard the scratching noises. Please help. Asap

 

Answer:

It sounds like you have an open sewer pipe or a ventilation issue. When you had your dishwasher uninstalled did the drain to the dishwasher get capped too? Maybe the dishwasher’s drain was accidentally left open. All you’ll need to do is find that and cap it like you did the water lines.

If its not an open waste line from the dishwasher, then it’s possibly a ventilation issue. The noise could be your pipes and that usually means the system isn’t able to breathe properly. You can either look for a broken vent line (poor glue jobs, settling, or accidental cutting are the usual culprits when it comes to disconnected ventilation lines) or you can try installing an under-the-sink Studor vent. It will act as a mini-vent and help rid your home of the odor.

My money is on the dishwasher drain assuming you had none of these issues until the dishwasher was disconnected.

 

Ask Your Own Plumbing Questions Below

To be honest, it’s difficult to explain such a complex issue as plumbing. It’s one of those cases where you can give too much information and too little very easily. If I haven’t made something clear please feel free to let me know!

If you have any plumbing issues feel free to ask questions in the comments below. I always forward your questions to a licensed master plumber with 18 years experience – he knows his plumbing (the hard part is putting his knowledge into the right words). On our first plumbing article we were able to help answer over 60 homeowners with their plumbing questions – maybe we can help you too! Click here to read them.

Thank you so much for reading Mobile and Manufactured Home Living! 

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67 Comments
  1. Lin Dziuk-Whitley says

    Off our master bedroom is a plastic pipe, about 3-4 inches wide. It is
    ( _| )shaped with an end cap at the corner where it both ends meet. The end cap was killed by my lawncare guy & now raw sewage leaks out. I stopped it up with a water bottle.( Dumb, I know) . My landlord is slow to fix things. I was going to try. It stopped leaking for a bit but has started again around the ( _ ) part of pipe

    1. Crystal Adkins says

      Hi Lin,

      That is probably a clean out but if you have sewage coming out you likely have a stoppage. All waste should be routed away from the home. Your trunk line could be off grade which is allowing this to happen.

      You will want to have a professional plumber come out and check the main trunk line for grade and stoppage and then have that ‘clean out’ at your master bath capped off properly. This is a bit of a health hazard and needs to be remedied quickly.

      Let me know how it goes.

  2. Rebecca Rhodes says

    We have what looks like soap suds coming out of the pipe on the roof. 2005 mobile home.

    1. Crystal Adkins says

      It sounds like your washer line is clogged which is causing the water (and soap suds) to back-flow into your ventilation pipe. Check behind your washer and make sure you don’t have water hitting your floors or walls and soaking in. You likely wouldn’t see it during regular day to day activities.

      The washer drain lines in manufactured homes are small (1.5-2″), this creates a problem with some washers. Now, you may not have a true leak since water is heavier than the suds it may be traveling exactly where it is supposed to go but the suds, being so light, are getting up into the vent line.

      In WV, they actually changed code on washer drainage. It now has to go into a 3″ trunk because soap builds up in the lines so easily.

      Find the clog, get that fixed and then make sure water didn’t leak and cause damage to your home.

      Best of luck! Let me know how it goes.

  3. Nichole Rodriguez says

    I am a new mobile home owner I bought a trailer as is thinking for some ignorant reason that it just needed to get a little TLC I was sadly mistaken!!!! I went to turn the water on and it was a disaster, apparently the guy before bypassed everything I mean everything except the sink, toilet, and tub/shower in master bedroom. Also tried to convert gas water heater into a electric water heater. I am a single disabled mother of 4 children living on $934 a month, so when this, what I thought was a great opportunity, has turned into a huge mess me and my children are in this home with no running water I am my wit’s end how much estimate I know would a entire plumbing assembly be

    1. Crystal Adkins says

      Hi Nicole,

      Sorry to hear you are having so many issues. Bypassing old plumbing supply lines is a very common thing in mobile homes that have been re-piped. Instead of having to remove all the old supply lines you just cap the old off and run new because it saves on labor and time. It’s also done on trunk lines sometimes.
      Converting gas water heaters to electric is also a fairly common thing. You can buy kits at all the home supply stores. There are many reasons to go from gas to electric but usually cost is the biggest reason.

      You really need to hire a plumber to come out and help you. I know money is tight but living without water is not really an option. Perhaps they will let you make payments?

      Let me know how it goes.

  4. Lequutta Rowdy says

    I live in a 2007 manufactured home and when I wash clothes I have to turn the water valves connected to the washer off after washing clothes because water ends up in the vent in my bathroom which is directly behind my laundry room.If I forget to turn the valves connecting to the washing machine off I get a build up of water in my air conditioning vent. Help driving me crazy I wanna know the problem before I call the Plummer.

    1. Crystal Adkins says

      Hi Lequutta,

      You probably have a dripping water hose that feeds your washer. It always drips but when you turn the feed off it drips a lot less. You’ll need to replace the washer connection hoses and reconnect them to your water supply line. While you’re down there try to move the lines away from the venting.

      Best of luck!

  5. Denise says

    I own a 1970 single wide mobile home. I am learning to be a DIY. Over the past 2y I have taken out and installed 4 water heaters due to various reasons. we have finally got it all under control except for my water pressure. the water pressure in my bathroom is fine. the hot water presure to the rest of the home sucks. I am a single mother and am hoping i can figure this out without a plumber

    1. Crystal Adkins says

      You need a pressure reducing valve. The high pressure is blowing your tanks and faucets out. I’m sorry, you need a plumber – a plumber could put a pressure reducing valve on your line for what one of your water heaters cost.

      You may contact your water company and see if they will put one on and bill you in installments (small water companies have done that in my area).

      Best of luck!

  6. David Pellett says

    Can’t get water to go down kitchen sink drain.ive plunged,crud comes up,I’ve snaked it.about to try liquid plumber.plumber as last resort

    1. Crystal Adkins says

      Hi David,

      You probably have grease build up. If that isn’t it the clog is further than your snake can reach. With the grease build up you can snake it but the grease just closes back off after the snake is pulled out.

      Best of luck.

  7. Robin says

    Hello Crystal,
    Thank you so very much for all this great info! Incredibly helpful! wonderful to discover it!
    We bought a 2bdrm 2bath 1965 Flamingo in 2008 that had only one owner prior to us. Yesterday we noticed water dripping from the ceiling in the shower/tub bath. Nozzles, spigot, etc. go up the one wall (or down perhaps?). We have a shutoff lever attached to the short adjustable (up or down) pipe right that extends down to the shower head that we engage when shower is off to prevent leaking. While the shower is running with the shutoff not engaged, the dripping immediately starts from the ceiling near the same distance the shower head is from the wall. When shower is off and shutoff engaged, the dripping stops. We are perplexed as to what would cause the dripping in that particular location out of nowhere. Any suggestions, clues etc. are greatly appreciated.

    1. Crystal Adkins says

      Hi Robin,

      It sounds like the pipe running to your shower head is spraying water up into your ceiling. Probably right behind the shower head or at the connection. It could be a connection or just an old pipe. Pretty sure a new line coming from your cutoff to your shower head (including a new shower head) will fix your problem.

      Best of luck!

  8. Lori McDaniel says

    Help please. I recently purchased a 1999 mobile home in New Mexico. About a week ago my tub started having a VERY slow drain. (By the time I’m done taking a quick shower, there are several inches of water in the tub.) I had a wet toilet paper in the tub issue (new puppy!), but the drain has a hose with a screen on it, so nothing should be able to get through it? And if something did, and there’s a clog … do I plunge it? Or use Drano? Or how do I get a snake down the drain if there is a screen (filter) on it? Thank you!

    1. Crystal Adkins says

      Hi Lori,

      You can use an auger to get a clog in the toilet. Slow drain is probably hair and you will need to remove the strainer.

      Best of luck!

  9. Jessie says

    We live in a single wide mobile home, in the country. Now, the problem (or so I thought) are the mice leaving an odd smell under our kitchen cabinets, but the smell is also from the master bathroom. Reading further into it, I realized that it might be a plumbing issue.
    The smell is “musty” like a wet, dirt smell or something like it. The smell comes from under the kitchen cabinets. There is no leak that I can see from directly under the sink, where all pipes are visible.
    Is there an idea of where the leak could be?
    Now, in the master bath, we put caulking on all the cracks on the bathtub walls, and even cut a hole in the wall that shows the pipes/hoses that connect to the faucet of the tub. We still can’t find a leak. But there is still a leak on the floor just outside the tub, along the sidewall. The carpet on the other side of the bathroom wall is never wet, but the wall on the inside of the bathroom near the floor by the tub does show water damage. Is there any guess as to where that leak could be coming from?

    1. Crystal Adkins says

      Hi Jessie,

      It could be leaking during drainage – as the tub drains or the toilet flushes or the water goes down the sink drain. Even a slow leak can cause the problems you’ve stated. For the toilet, you can get a dye for the water that can help you locate a leak. For the drains and supply lines, you can have a pressure test done to find any leaks. It’s sometimes pretty hard to find leaks, they aren’t always obvious.

      Best of luck!

  10. Amanda says

    We live in a 1981 trailer and have several issues with the water and plumbing. It’s seems as if there is a blockage somewhere. Our waste water is now coming back into the tubs and toilets and will randomly have a slow drain but will fill back up. We now have no water for no explainable reason. What could we do about the water backing up into the tubs and toilets and having no water?

    1. Crystal Adkins says

      Hi Amanda,

      You either have a massive stoppage or some serious airlock. If you have a septic tank it could be full or your trunk lines could be graded improperly (maybe a strap fell?). Not sure why you would lose water supply. If you can get a plumber there and have them check the septic tank (if you have one) and/or run their industrial snake through your trunk lines and vent lines you should be able to find out whats going on pretty easily.

      Best of luck!

  11. Hazel w El says

    I have a 1986 doublewide in a trailor park and since moving in there is a horrible poopy smell coming from the master bathtub. It is worse when it’s hot out. I am coming near the rent to own and I love my home so of course I would like to purchase. The park has replaced all the plumbing under the home and the vent under the master bath sink. Now with it being 100 degrees today my whole house smells. Its definitely coming in the tub. What can this be?

    1. Crystal Adkins says

      Hi Hazel,

      It sounds like you have a ventilation issue. Either your vent lines from your tub/bathroom have separated or there is a clog (birds and critters love vent lines). You’re gonna want to check that all the vent lines that go into the roof vent for that side of the house are healthy. This is especially important if your water heater is on the other side of the tub wall (like so many mobile homes are designed). Pressure and age can cause separations.

      You’ll also want to go under the tub drain and make sure the P-trap (or S-trap) is healthy (it’s holding water and isn’t separated or damaged) and that the drain lines from the toilet and faucet are properly routed to a vent line.

      Luckily, ventilation issues aren’t terribly difficult to repair. A plumber can always reroute if needed.

      Best of luck! Thanks for reading MHL and please let me know how it goes!

  12. Jennifer Mills says

    Hi we woke up to a wet floor in our master closet water close to is washer dryer heatpump and the condenser for the ac i have check for all and all seem to be ok the ac confessor i had to uncolg it wasnt ddraining very well however i also noticed the water level in the toliet master bathroom is low and it rocks when you sit down the floor is still wet and i went under the home and marked the water ring just to be able to tell if it gets better or worse the part i unclogged for the ac had water to the rim of the tray until i unclogged it it seems to be draining fine i just want to ensure that that can cause it it seemed like a awful lot of water could the toliet have anything to do with it there is a faint smell coming from the bathroom as well

    1. Crystal Adkins says

      Hi Jennifer,

      Sounds like you need to at least put a new wax ring on your toilet. They are $14 and it’s not a hard project at all (lift the toilet, remove the old wax ring and put the new one down, and replace the toilet). It would/could only leak when you flush which absolutely can cause a smell since its waste water.

      While replacing the wax ring you may want to go ahead and have that subfloor replaced (it’s a ‘find the leak first’ but while you’re there you might as well do what you can while it’s easy kind of thing).

      Best of luck!

  13. Shawn says

    I been living in a 97 Fleetwood Mobile home for about 3 years and over the years when the washer is in draining I can hear the backing up sound in my sink never thought it was a big deal. But week ago there was water running into my kitchen coming from the washer. When the washer is draining on rinse/spin cycle it will overflow out of the pipe but as soon as I shut it off the water will drain down the pipe and thats when I hear the gurgle sound in the wall behind the washer and water coming up in my sink. At first I thought it was clogged so I snake out the pipe in which it was clean too using pouring boiling water but it still no results. Iam DYI guy but yet not the best to where Iam looking for suggestions in what it most likely be before I start taking apart pipes and even replacing check vent.

    1. Crystal Adkins says

      Hi Shawn,
      Sorry, I overlooked your comment till today. I’ve been told that the new washers require a larger drain line than we’re used to needing as they release the water a lot faster than the old washers did. You may just need to add an auto vent to that ‘branch’ (laundry/kitchen/bath) so that there’s adequate venting. You may also want to change the location that your laundry room drain enters into the main drain trunk (further ‘down’ from the kitchen drain perhaps).

      It definitely sounds like a venting issue but without seeing the system I can’t be much help. Sorry – best of luck!

  14. Anne Baade says

    Would improper installation cause a 3″ sewer pipe underneath my home to disconnect at a seam? I have been without commodes for almost a week, due to the warranty company denying the claim. Improper installation is covered, as is normal wear and tear. The warranty company is stating the problem is not caused by either, even though the pipe has come apart, and apparently the installation was done without the proper drop.

    1. Crystal Adkins says

      Hi, Anne,

      I don’t really understand which warranty company you are speaking about but as far as I know the toilet manufacturer wouldn’t be responsible since this is a plumbing pipe issue and not a toilet defect. The manufactured home builder wouldn’t be responsible if you installed a new toilet. Now, if this home was recently purchased and installed then your installers could be liable for not properly installing/sealing the pipe. However, if you signed off on the paperwork and/or the home has been in place for over a year and has settled any at all and you haven’t had it re-leveled then they won’t be liable either. That’s why so many people have so many horror stories about manufactured homes – there’s a way out for every issue, especially when it comes to installation issues and the majority of issues that homeowners have are due to improper installation. It’s a vicious circle.

      You could waste a lot of time trying to get someone to repair this so you’ll probably want to go ahead and get the toilets in working order as soon as possible on your own and then use the professional plumber’s opinion to try to have the cost reimbursed. Reconnecting a waste line would only take a few minutes time.

      I’ve seen ‘warranty’ issues take 3 years to be settled. Best of luck!

  15. Adam says

    Very great article!

    I have been battling a plumbing problem for a few weeks now and I cannot get to the root of it. To go in depth here.. I have a 2 bathroom manufactured home. My kitchen sink isn’t draining quickly anymore, and neither is my shower, or bathtub in the other bathroom. When my wife does the dishes in the kitchen sink, water seems to come up in both tubs. When the washing machine drains, water comes up very fast in my shower, and I believe some goes to the back bath as well. My toilets seem to drain fine and go straight to the septic. I have ran an auger through the main drain line completely and so have some hired plumbers. They think I have a clog near the bathroom with my shower, but said it will cost $1000 to dig their way back there to get to it. I can crawl back there myself though. I have also noticed that when looking back towards my back bathroom with the tub, if the toilet back there is flushed, after a few seconds, I will see water dripping off to the side. I am wondering if it is coming from the clean out. I also thought I seen water elsewhere under the house but haven’t crawled all around yet. Also, after running water pretty much anywhere, the sewer smell is god awful! Any ideas? Wasn’t sure if you think ventilation or a clog? Also, I see no vent pipe running out of my roof, but have seen an air admittance valve under my kitchen sink. Thanks in advance!

    1. Crystal Adkins says

      Hi Adam,

      I’m going to put my money on this being an airlock/ventilation issue. Whenever someone mentions odor and slow drainage it is almost always a ventilation issue. You need (better/unclogged/working) ventilation off the main trunk line and auto vents under each sink wouldn’t hurt anything. Your main vent stack(s) could be clogged or seperated and if it’s not easily repaired you can run a new vent (just make sure you put it in the right place depending on your plumbing design).

      Best of luck!

  16. Kathy Riegler says

    HELP! We have a 2003 double wide mobile home and had the septic tank sucked out for the second time a few weeks ago….we put on those stack things over septic tank also so we won’t have to dig so far next time….now we have a foul smell in the master bathroom ….we replaced all vents in home and the smell is still in MB noticed mostly after taking showers……when septic was full I had to plunge the heck out of the shower drain to try to get it to drain, it didn’t though….(shower and tub are separate in Master Bathroom) ……also our washing machine leaves clothes smelling foul….don’t know if these 2 problems are connected but thought i should mention it….replaced vent in wall next to washing machine also….Please help me to figure out the cause of these smells and how to fix them for as cheap as possible….

    1. Crystal Adkins says

      Hi Kathy,

      It sounds like you are having a ventilation issue. A venting pipe may be open somewhere or clogged. If the venting is not right it can cause the water in your P traps to get sucked out which will cause the odors. You’ll want to have a plumber make sure your P-traps are installed right at every drain (tubs and sinks – a toilet has a p trap made into it) and then you’re gonna want to have the vent lines checked to make sure there are no separations or clogs and that the design is correct (vents have to be placed in the right places to work properly). An auto vent can be used under your sinks but you really need the main vent pipes sticking out of your roof to be healthy and working like it should.

      I’m not sure about the washer issue. If it isn’t the water it has to be bacteria growing somewhere. If your washer is a front load you’ll need to clean the rubber gaskets with bleach (get in every crevice with a q-tip) and then keep the door open so it can dry out between loads. The foul smell is a common issue with the front loading machines.

      Let me know how it goes! Best of luck!

  17. Heath says

    Hey Crystal, I really hope you can help. My wife is pregnant and so smells hit her really hard. We have a horrible odor coming from our master bathroom. It fills the whole house sometimes. It smells like a combination of mildew and/or gas. It gets worse when we run a lot of water or when it rains. We bought the mobile home used and put it on some land that we own. Brand new septic tank. We discovered that the previous owners installed an elbow pipe underneath the tub at some point and not a P-trap. We thought that was the issue and replaced it, it helped, but didn’t fix the issue.

    1. Crystal Adkins says

      Hi Heath,

      Sorry, it took so long to reply! I lost your comment. Since you did replace the elbow with the p trap I’m gonna put my money on the previous owner doing something to the venting. If they didn’t know the very basic plumbing rule that a p trap needs to be on every tub and sink (toilets have them built in) then they probably didn’t know there was even such a thing as ventilation.

      You’re gonna need to track down your entire venting system and find out where the issue is. You may get a little help by installing an auto vent under your sinks too.

      Best of luck!

  18. Paula Hunter says

    I’m hoping you can help direct us in the right direction. We live in a 1996 manufactured home. When the wash cycle goes to rinse, the kitchen sink gurgles and we have a sewer smell. We had the septic pumped and they checked the outside lines and said all was good on their end. We had a plumber come in and replace the vent under the kitchen sink and also the vent in the wall by the washer and snaked the pipe near the washer. It did not correct the problem, still gurgling and sewer smell. I really do not know what to do next or what to tell the next plumber to investigate. I really don’t want to keep spending money and not fixing the problem. I hope you can help with suggestions, etc… Thanks.

    1. Crystal Adkins says

      Hi Paula,

      Hmmmm, this sounds like a ventilation issue. Since nothing else has worked, try cutting and capping the original washer line and then running a new washer drain line and tying it into the trunk waste line under the house further downstream than where the kitchen lines are attached. This will allow the system to get the right ventilation route and allow the auto vent under the kitchen sink to be able to work like it should (inhale instead of trying to exhale). Also, most manufactured homes should have a vent going out of the roof for the washing machine (especially if it’s grouped close to the kitchen) instead of an auto vent in the wall. I’m not sure why yours doesn’t have it.

      Hope that helps! Let me know how it goes!

  19. Felicia Grant says

    My family and i lves in a double wide manufacture home since 1996. Ever since my dad past away 8 yrs ago the house has been having some terrible issues, such as the plumbing. Underneathe the house one of the pipes has come loose and everything s running straight down into the ground, toilet does not flush completely, you can gear water running right now. The smell is horrible, we have to wait days at a time just to use the washer. Please help, my mom is a double amputee, senior citizen, and widower on a fixed income.

    1. Crystal Adkins says

      Hi Felicia,

      You need to get under that house and fix those pipes somehow. Churches and local charity organizations will sometimes help you work on the home, especially if human waste is just going on the ground (that’s really bad for the environment and for everyone living there).

      Pipe isn’t that expensive thankfully.

  20. Leslie says

    Hi, my kitchen sink is clogged. I have checked all pipes under the sink and no blockage is there. I went to the store and bought a snake. I snaked it at least 15 times, nothing was found on the tip of the snake and clog was still there. I have done the baking soda and vinager, plunger and chemicals. So far no luck, and thoughts into where I need to check on a double wide?

    1. Crystal Adkins says

      Hi Leslie,

      Sorry it took so long to reply but I was waiting on my master plumber friends to reply. Here’s what he says:

      “Sounds like it’s a grease clog in the kitchen line underneath.. a snake will go through grease then close back off. Bout need to blow it out either with drain king on end of hose (this kinda takes knowing what to do)… or cutting line underneath that goes to the kitchen and or clean or replace.”

      Best of luck – let me know how it goes!

      1. jessica artz says

        e had the same problem last week. We used drain liquid and a snake and finally got free. Now my hubby went under the house to make sure we didnt have a leak etc. There is NO water under the house,but there is a huge bubbled out part the plastic lining and full of water! My hubby had us turn all the water in the house on while he was under there and no NEW water is going into this bubble,so that tells us that unblocking the clog is letting the water flow the way it should. My question is,s that water from having the block? Is there an overflow that allowed it to fill up? and how should we go about emptying it ourselves?

  21. Laura says

    Hi,
    We just installed a new toilet and it was working fine for about 5 flushes. We then unhooked and installed a new sink. Unfortunately our supply lines and drain were too short and we left it all until I could go back to the store. The next morning it flushed right the 1st time, but then started having a very weak flush, slow drain, and gurgling. We have the sink hooked up now, and installed a new vent under the sink. Of course, we’ve plunged it several times, just in case, but no luck. Our mobile home is 17yrs old. Is there anything else we can do? Thanks

    1. Crystal Adkins says

      Hi Laura,

      The drain probably dropped when you unhooked it for the sink which caused it to hold water underneath and cut the vent off to the toilet. The drain underneath is basically just a p trap so look under the toilet and make sure that waste pipe is well-attached and that the trap is holding water.

      Best of luck!

  22. Jeanette Hammons says

    I need HELP. I’m 79 and husband is 86, unable to do repairs so I’m healthy as a horse
    and I crawl around under our doublewide if a problem happens. Here’s my problem.
    In Jan 2016 I paid someone to change my shower drain (bathroom #1)and washing machine to drain out in my yard. (we live way out in the country). All of a sudden the washer water drain is backing up in my commode and also in the 2nd bathroom tub. Along with commode waste. I find the washer drain tee’s into a vertical line going toward the outside drain but also toward the septic line. Do you have any idea what I need to do.

    1. Crystal Adkins says

      Hi Jeanette,

      It sounds like your sewer trunk is clogged a little and is causing the stuff to backup and toilet trash to come up into the shower. You may want to cut and cap where the washer water goes to sewer line.

      Best of luck!

  23. james safari mwamure says

    hi thanks for the knowledge you provide to people.its amazing. i would like to know if you have lessons and certificate courses which one can take for free and online

    1. Crystal Adkins says

      Hi James!

      Thanks for the kind words. I don’t offer anything but I’m happy to answer questions via comments. It may take me a few days but I get to them eventually!

      Thanks!

  24. Sue Durst says

    Crystal
    I hardly ever do this but felt compelled to write this time. Your website is well organized and well written, especially since you aren’t a master plumber yourself. (my heart sunk when I read your post about not being a team anymore, I am sorry) Regardless, I can tell the website is/was your baby and I bet you wrote most of the extremely informative, easy to understand articles yourself (of course, based upon information provided by the master plumber). I noticed the last Q & A was early 2016 so I am thinking your heart is not in it anymore :( I just want you to know that I have used the information you provided many times for various mobile home issues/projects with great success and your efforts (and master plumbers expertise too), are greatly appreciated.

    If you don’t want to continue with this site, I highly recommend doing another website of your choosing. You have a way with words :)
    Sue

    1. Sue Durst says

      Oops i guess your site is updated, my apologies. But my point is…thank you so much for all you do!

    2. Crystal Adkins says

      Thank you for the kind words, Sue!

      Admittedly, after 5.5 years of blogging, and over 500 articles about mobile and manufactured homes, I do have to put in a little extra effort to get motivated to write new articles! Apparently, that is common for bloggers after many years.

      I still love the homes and the people in them, though! My 1978 single wide completely changed my life for the better and I’ll forever be thankful.

      I try to publish 2 articles per week but sometimes life gets in the way. While I can’t really provide plumbing help any longer (outside my comfort range), I can at least try to point people in the right direction and I’m happy to do that.

      It was a good run while it lasted! Thanks so much for the kind words!

  25. Doug says

    I’m thinking maybe it’s just easier, and less expensive, to just turn on the water, flush the toilet, in that bathroom once a week!
    Re-circulating pumps aren’t too expensive. But, then, there’s the cost to put it in. And, then, the water heater runs so much more to keep that water hot all the time.

  26. JoNell says

    Me and my hubby are new to this we just purchased a 1996 single wide home with 2 bed 2 bath and just today the whole plumbing seemed to work fine until I washed the dishes. Never had a issue with drainage till now- the water wouldn’t go down in the sink I removed the drain stopper from the sink I was washing dishes in and neither water to go down we cleaned out the pipe but still having issues…just trying to find some answers

  27. Kiani says

    We just installed a brand new sprayer for our kitchen sink and now about a month later the water coming from it stinks like a grease trap! The old sprayer never had this issue and nothing in the plumbing has changed. The smell does go away after running it for a few minutes but if you let it sit again for about 20 minutes the stink is back. The smell hasn’t affected any other faucets… I do know that the smell is horrible and whatever it is in the water almost killed one of my plants… Help please! Oh and PS…. I’m on well water. Thank you!

  28. Lauren says

    Hello Crystal,

    Thank you so much for answering perplexing plumbing problems! I’m a “do it yourself” if at all possible person. I recently purchased a single wide with one bathroom. The tub faucet in that one bathroom makes a “banging” problem when I shower. It happens when I fill the tub with water to take a bath as well. If I turn on the hot water full blast, it does not “bang”. I found the access panel to this tub inside a closet. Do I need to pull the access panel and do something in there?

    Thanks again, Lauren

    1. Crystal Adkins says

      Hi Lauren,

      I’m so sorry, the master plumber and I are no longer a team so I don’t have a professional to answer questions any more (it was good while it lasted though!). I want to say you need to replace a washer in the faucet or maybe install a strap on your water lines but I’m not a professional and my knowledge only goes as far as helping Mr. plumber on jobs during our 20 year marriage. I was able to find a few articles that may be helpful though (the first one seems dead on):

      http://terrylove.com/forums/index.php?threads/help-knocking-pipes-in-shower-only-when-handle-in-in-the-middle.29939/
      http://www.womenyoushouldknow.net/fix-friday-quiet-pipes-shake-rattle-roar/
      https://dengarden.com/home-improvement/How-To-Fix-Noisy-Shower-Pipes
      http://homeguides.sfgate.com/repair-shower-valve-its-making-noise-101846.html
      http://homeguides.sfgate.com/banging-noise-water-pipes-shutting-off-shower-87485.html

      Sorry I can’t be more help! Best of luck!

      1. Lauren says

        Hi Crystal,

        Thank you for your response!

        I’m sorry you and the master plumber are no longer together. (not for answering my question, but for you)

        Thank you for the links and I’m going to open up the panel with all the tub valves in it this weekend.

        Take Care,
        Lauren

  29. Cindi Eshelman says

    I live in a 70’s mobile home. Just recently, we’ve been having problems with air bubbles coming up in the toilet when we shower, and the toilet not flushing well. I took the toilet off and had it snaked out, which seemed to fix the problem..until yesterday. One plumber I called out said the was a bow in the drainage pipe under the toilet (wanted 4000+ to replace it). We made sure the vent stack was clear (snake came back completely dry). What now? Can I replace the pipes myself?

  30. Matt W. says

    We recently had to install a new sewer line connecting 12 RV sites to an existing sewer line that has 4 sites and 1 deluxe cabin (not roof vented). The cabin is the last sewer connection before the line turns, and goes 25 feet to a 2000 gallon tank. Odor complaints began after we did this (could be a coincidence) about 3 weeks ago. It is intermittent, folks check in and it’s fine then 3 hrs later it stinks. We tried to determine the exact odor, sewage, sulfur, rotten eggs, what is it, etc……….We augured the main line from cabin to tank. We put a vent coming out of the cabin in (before the drain) and up and outside of the cabin. This park model is not vented through the roof.

    Then after a rotten egg smell I thought of bacteria in the hot water heater, then water sitting in traps and causing odor there. So I throughly flushed the heater with peroxide. Odor returned.

    Spoke with my local septic guy and he said a couple things. The pee traps could be cracked, clogged (we’ve dumped plenty of Drano), or just bad. They smell when they dry out. He believes the odor is sewer.

    It may be sewer……when someone dumps, or something passes by, intermittently, there is an odor. Then gone. BUT we vented the line coming out of the cabin and drain. Maybe this should not be vented because of creating the wrong pressure. Should we vent before as well? Is it something already in the cabin piping?
    I had a galstay in the cabin 2 nights ago. And let me know if an odor returns.
    It returned.
    We just aired out the cabin and replaced two Studor vents under 2 sinks. Is there one in the shower? We will close it up later and continually check later today, etc…..
    I’m now thinking the upward vent we attached to the drain line outside the cabin is creating a pressure problem inside. Or there is a Studor vent under the shower we missed.
    Your help is greatly appreciated

  31. Veronica says

    I have a double wide mobile home and we have noticed leaking at the p trap. We replaced the washer and it still leaks. I have a bucket under it to catch the leak. Yesterday I noticed that the underside of all the kitchen cabinet fascia are warped and seemed damp. I noticed that when putting the p trap back on you have to lift the drain pipe that runs through the floor because there is a gap where the p trap connects. The pipe that connects through the cabinet floor appears to lift up out of the floor when we lift it to attach the p trap. Is it possible that the straight pipe going through the floor of the cabinet is not connected properly and causing it to leak under the cabinets? How hard would that straight pipe be to fix?

  32. Jim says

    I have a 1999 double wide with a 40gal electric water heater. I cool to warm water coming to my faucets (all brand new) and no hot water.
    Also, the WH hot side gets hot to the touch and the cold side gets warm but still only warm water at the taps. If i release the Pressure valve the hot side of the tank gets hotter for a few minutes then it turn cool. I am thinking there is a 3way valve somewhere underneath the home, but i can’t seem to locate it. Any ideas?

    1. Crystal Adkins says

      Hi Jim,

      Unfortunately, this is one of those issues where it would be near impossible to answer without looking at it. Have you checked your elements to make sure they are working properly? If so, you’ll want to make sure you’re water lines aren’t crossed and your wiring and amps are the right size. Other than that, it would be hard for me to guess what else it could be.

      Best of luck, let me know how you end up fixing it!

  33. Ilene Reff says

    I am interested in purchasing a new park model and would like to transfer the 40 gal water heater from the one I have now the heater will be placed into a dedicated closet and due to a loft above I am not able to vent through the roof can it be vented through a sidewall.

    1. Crystal Adkins says

      Hi Ilene,

      The answer is going to depend on your location so I can’t give you an exact answer. I can say that you usually can vent off a sidewall as long as it’s an exterior wall and the distance is minimal (a few inches). Vents can get pretty warm from a water heater.

      You’ll need to call a plumber to make sure you’re within regulations. Best of luck!

  34. Jeni says

    Thank you Crystal for this very informative article! I had some issues I had questions about and found answers here. Thanks so much!

    1. Crystal Adkins says

      Thanks Jeni!

  35. Suzanne Melton says

    Great article, Crystal…it’s almost as if you have a close, personal friend who is a plumber!

    The article doesn’t mention whole-house water filters but, if anyone reading this is considering have one installed, don’t forget to change the filters every six months (April 5 and October 5 here).

    If the filters aren’t changed, they will eventually “explode” and tiny little carbon particles will travel all though the system.

    1. Crystal Adkins says

      Hi Suzanne!

      I may know one or two plumbers…lol…Thanks so much for the tip! I’ll put filtration systems on my t-write list! Always good to hear from you!

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