Plumbing Issues for Manufactured Homes

To keep a manufactured home’s structure efficient, vent and drain pipes are smaller. This can make them more prone to damage, which if it leaks can damage your floors primarily of wood and drywall. Be wary of leaks, odors and noises as this may be hinting to a problem in your plumbing system. If in a compact manufactured home, the plumbing fixtures may be smaller and harder to replace. If living in an old “mobile” home, (built before 1976 in the U.S.) be sure to check if the plumbing systems are updated to code.

Image from How To Minimize Moisture Problems In Manufactured Homes (

As manufactured homes descend from the ‘mobile homes’, their build and problems are common. Therefore in this article they will be used interchangeably to be able to cover all the plumbing issues you may encounter.

Know your Pipes 101

To keep the building compact and efficient, many manufactured homes may use smaller drain and vent pipes of 3” diameter, compared to the 4” diameter of site-built homes.

A good tip from Mobile Home Living is if your supply pipes are white, cream or a medium gray, have them changed as newer building regulations advise against their use or are banned completely. These supply pipes of ⅜” to 1” is where your water inlet comes through. This then branches off into the different fixtures to dispense water to fixtures like your sinks and showers. (1)

Drain lines on the other hand are bigger at 3” and use other systems to work, such as gravity, traps and vent pipes for waste removal and to prevent odor and wastewater backflow or clogging.

With your vent and drain pipes being smaller, these make it more susceptible to problems in drainage and venting. (2)

Spot the Issues

Be cautious of these signs around your home as they may be an early signal of plumbing issues.

Sounds in your Walls: When your walls start making sounds while water drains, this could be an indication of a ventilation problem like a clogged vent pipe. (2)

Damaged Floors: As the plumbing pipes of manufactured homes run under the floors, leaking pipes can lead to damaged floors. Depending on the type of wood used for flooring, some can readily absorb water quicker than others causing them to rot. (2)

With the home undergoing transportation via truck, it takes time for the pipes to settle after installation. These may shift a bit before finally settling into its place. This movement can cause rigid pipes to loosen or crack, leading to a leak. If the leak is at a joint, simply tighten the connection, add joint fillers or a rubber leak tape. Cracked pipes should be replaced.

If the moisture is coming from dripping faucets and taps, replacing the washers usually solves the issue. This is often due to an unfastened or damaged washer, but you may also deconstruct your tap to check for any loose parts or blockages. (3)

Smelly Odors: This could be a sign of clogged drains, especially when you cannot trace its source. Be sure to unclog drains quickly with muriatic acid or water pressure to prevent water contamination. (3)

Low Water Pressure: If only certain taps are giving weak pressure, check the faucet aerators. They may just need to be cleaned but if clogged from sediment accumulation, you’d have to set up a new system. If you’re cleaning them too often, consider replacing the pipes for a different material. Galvanized pipes create lime build up more than plastic pipes, due to the reaction between water and zinc.

If it’s happening throughout the house, check in with your neighbors to see if they’re undergoing the same issues with water pressure as you are.

Frozen Pipes: Firstly, make sure your pipes have proper insulation around them, as they typically aren’t as protected as those in site-built homes. This ensures the cold doesn’t easily get to the water freezing them inside. Make sure you run all the water lines in the winter months. Another tip is that copper pipes are more prone to freezing than plastic ones. (3)

Image from Diagnose And Repair Venting Issues In A Mobile Home Plumbing System (

Key Plumbing Tips

So that’s as far as common plumbing issues in manufactured and mobile homes go. If you’re in the process of buying a home, try and already safeguard your plumbing by insulating the plumbing and opting for certain plastic pipes. Have these specified if you’re customizing your manufactured home! Also be mindful of the pipe locations to easily detect problems.

Hopefully this article helps on the tell tale signs of a problem before it escalates into a huge problem!


  1. Adkins, C. (2022, March 29). Mobile Home Plumbing Guide. Mobile Home Living. Retrieved May 2022, from
  2. Haley, C. (2021, January 21). How does a mobile home bathroom work? Hunker. Retrieved May 2022, from
  3. Preston, G. (n.d.). Plumbing in mobile homes and common plumbing issues. Plumber. Retrieved May 2022, from