Plumbing in manufactured homes can be a great DIY project. As long as you can work with tools and understand the basic concepts of the plumbing system, you should do just fine.
A manufactured home plumbing system is a more simplified version of a stick-built home, but that simplicity is not a bad thing, those differences makes everything much more accessible and easier to work on.
Differences Between Plumbing in a Manufactured Home and Stick-Built Home
Manufactured home plumbing systems are a little different than stick-built homes. The main water supply connection is usually found under the edge of the home, near your outdoor hose bib (where you connect your garden hose). The supply lines are usually housed in the middle of the home or on the side, depending on the layout and location of your water heater. Plumbing pipes are rarely housed within the walls of a manufactured home, but are stubbed straight through the floors under the sinks.
Some manufacturers may have used the lightest, and often the cheapest plastic piping or galvanized metal, so replacement will be needed eventually in older homes. Galvanized pipe is known for rust issues and and the plastic piping (polybutylene) are known to corrode and cause leaks. There’s also issue with the connections. If you find yourself plagued with leaks, go ahead and re-pipe the home, if possible. In the end it will be far cheaper, and less stressful, than trying to fight with old material and patches. Area plumbing codes will be the ultimate factor in deciding what material to use but Pex seems to be a well received product, as long as the connections are high quality and a proper seal is made.
Clean outs and overflows are not used very often in a manufactured home, though there is still a ventilation stack or soil stack as I’ve heard some call them. The stack is a small pipe sticking out of your home’s roof and carries the bad fumes and gases from waste away from your home. You have to have one for your plumbing to work properly.
Know How to Turn Your Water Off
You need to know where and how to turn your water off in case of an emergency, or before any repair. Being able to shut your water off quickly can be the difference in a complete disaster and a small inconvenience. The main stop valve should be around your outside garden hose water connection (hose bib as some call it) and most are easy to get to on a manufactured home.
If you can’t find you connection, then you need to be able to cut your water off at the source: at the main water meter (assuming you are on a city system) or in your pump house if you are on a well system. If you are on city water you will need to own a water meter key in the shape of a five-sided pentagon to remove the cover. They come in different sizes so make sure you buy the right one. You can also use a wrench and long screw driver for a makeshift key – place a wrench on the vertical (or straight up and down) and the thread the screwdriver through the whole at the end of the wrench. The two tools will look like a T. Use the screwdriver to turn the wrench. This article about turning off your water supply is handy if you want to read more.
FYI: It is smart to have cut off valves at every water source (faucet, tubs and toilet) however, if you have to repair or replace a supply line anywhere within your home, you must cut the main water supply off. There’s a lot of pressure in those lines and it needs to be reduced before you start cutting into them.
How Basic Plumbing System Works
Basically, there are 3 parts that make up the whole plumbing system. Supply lines do exactly what they say they do, supply the water. The next component is the drainage lines and they drain waste. Simple enough, huh? The last part is the ventilation lines.
Here’s the simplest schematic I could find to show you:
Know Your Plumbing Pipes
You will need to know what type of pipe and fittings are used for each sub-system. There are basically 2 types of piping used in plumbing- metal and plastic. Most plumbing in manufactured homes use plastic. Plastic pipes include polyvinyl chloride (PVC), chlorinated polyvinyl chlorine (CPVC), PEX pipe and PolyPipe®. Metal plumbing pipe consists of copper, stainless steel and galvanized steel. Not all pipes are as useful or effective as others, and each type is used for a specific purpose in plumbing.
Polybutylene was used in all types of homes, including manufactured homes, from the late 1970’s to the mid-1990’s. Several lawsuits were filed on behalf of millions of homeowners due to issues this material had. If you had any type of bleach in your water, and most city systems do, the pipe would break down and cause leaks and complete blowouts, usually within 5-10 years. You can’t buy it anymore but it’s still in more homes than it should be. It’s a medium grey color and will have PB and some numbers on the side. If you have this in your home today, you need to replace it and then go buy a lottery ticket cause you have been very lucky to have had it this long without any issues!
If you are looking to buy an older manufactured home, do not buy it with this kind of pipe in it. Make the seller replace it or have them take the replacement cost off the price of the home (there may even be local and federal laws prohibiting the sale of a home with this type of pipe in it).
PVC is a type of plastic plumbing pipe primarily used to transport high pressured water. It is available in several standard sizes, ranging from ½ inch to 4 inches in diameter. PVC pipe is only made to handle cold water, as hot water will cause the pipe to warp. It is generally white in color, though a few varieties are gray.
CPVC pipe that has received an extra chlorination. It comes in a distinctive yellow color, and can handle both hot and cold water. CPVC is more flexible with substantially thinner walls than PVC pipe, and has the same outer diameter as copper pipe, which increases it’s range of uses.
PEX, also known as cross linked polyethylene pipe, was first manufactured in the 1920s, but has become more popular in recent years. It shares the same outer diameter as copper, and can be used for both hot and cold water. However, PEX pipe has a much higher heat resistance than most other plumbing pipe, and is often used in water-based heating systems. It comes in a creamy white color, as well as red and blue which is used to denote hot and cold pipes respectively. I, and my husband who has been a master plumber for 18 years, absolutely recommend you replace your water lines with PEX when the time comes to update. You can use special fittings to secure the connections by hand or rent the tool needed to connect the lines. Pex, in our humblest of opinions, is the best pipe for water supply lines and is so much easier to install than anything else.
PolyPipe is a thick black pipe used to transport highly pressurized water, usually to and from the home. It is used almost exclusively outdoors, and is usually buried underground to prevent freezing. PolyPipe® is extremely rigid, and is rarely used for other purposes.
Here’s a good video about a double wide re-pipe:
Copper is the most common type of plumbing pipe used in the home, although it is more expensive than plastic piping. Copper is especially resistant to corrosion, and can withstand high temperatures. Copper pipes come in three different sizes – type M, L, and K. Type M has very thin walls, while type L is of medium thickness, and type K is the thickest of the three.
Stainless Steel pipe is less not as commonly used as other metal pipes, as it is more expensive and harder to find. It is primarily used in marine environments because it can withstand salt water, which would erode most other metal pipes. The price makes it less desirable for other applications, or in safer areas where a copper pipe would perform just as well.
Galvanized pipes have been used in homes for years, typically to carry water in and out of the house. The galvanized coating prevents rusting, and gives a dull gray appearance. Use of these heavy duty pipes is diminishing, as it is being replaced by PEX pipe, which is less expensive and just as durable. Galvanized pipes typically come in sizes between ½ inch and 2 inches in diameter.
Nasty smells and weird noises
No, it’s not your teenager.
Notice the yellow vent lines in the schematic above? It’s the small pipe sticking out of your roof. There are wet vents and dry vents, the roof pipe is considered a wet vent. Without proper ventilation, you will encounter several issues. The worse being nasty fumes and a build up of gases that could cause some serious issues.
Ventilation makes your pipes remain at a neutral pressure. Without proper venting your drainage slows and the water in your P-trap goes away, which in turn releases the nasty gas/fume combination.
If you hear weird sounds coming from your walls you most likely have a venting problem. Think of a soda bottle: when you tip it half way, the liquid smoothly flows but when you turn it completely upside down, it makes gurgling sounds and the soda pours out slowly. That’s what happens when there’s not enough ventilation or air flow. If you have ventilation issues you can fix it yourself fairly easily.
Water is one of the most destructive forces on earth. It will always flow the path of least resistance. Plumbing in manufactured homes will rarely be inside a wall so you won’t need to worry to much about damage to walls, it will be floors that get the most of the damage and then just spread from there. Most plumbing pipes run under the home and up through the floors. A monthly check under your home is a good idea. Your flooring is most likely made of a composite wood and that stuff loves water – it just soaks it right up and eventually bows and rots.
Leaks, clogs, low pressure, obnoxious odors and having no hot water are just a few of the issues that you may encounter. If your manufactured home is older you may have to replace the system entirely. There’s lots that can go wrong! We’ll try to cover them all in the future.
Leaking can occur in a couple of different places on a faucet. It’s probably easier to just replace the whole unit than repairing. If you are especially attached to your faucet, this article about fixing leaking faucets should help.
If you have a clog in your sink, a plunger can work well. They make a smaller plunger for the task. If you have a two sided sink, close off one side by stuffing a rag into the drain (cut off air) and plunge the other side, then switch – keep doing it until the clog is gone.
If you have clog issues frequently, it may be time to find the underlying issue. You can remove your p-trap, if its closed off with grease you can clean it out or replace. You may need to add a dry vent to the next closest sink.
If You Do Need a Plumber..
If you do need to call a professional plumber, my best advice is to ask every plumber, and any construction worker for that matter, if they actually passed the licensing exam or if they were grandfathered in.
If they say grandfathered, get a different plumber. I’m serious.
Allow me to explain: Here in WV and a couple other states I know of, they initiated a law making everyone on a construction site to carry a license. They offered 3 types: apprentice, journeyman and master. However, when the law first took affect, they gave everyone a time frame to apply and automatically receive the license as long as they paid the fee and signed a paper ‘confirming’ you had the experience needed to qualify for one of the three licenses. No one had to take an exam to prove their knowledge. Now, the state has hundreds of so-called master carpenters, electricians and plumbers that aren’t as knowledgeable as they should be.
Also, ask for references and actually call and ask them how the job went.
I hope that helps you. If you have any questions please feel free to ask them in the comments. My husband would be more than happy to answer any questions and yes, he took the exam to prove his knowledge. 😉