Manufactured home plumbing can be quite different than conventional home plubing, especially in older mobilehomes. Many plumbers will not work on mobile homes, partly because things such as tub faucets aren't standard.

If you have an older mobile home, you probably have metal galvanized pipes, which are no longer installed for waterlines. Homeowners who have galvanized will notice a loss of water pressure and increasing rust particles due to corrosion. The only solution is to replace galvanuzed pipes with a different material.

Copper is quite expensive, and is time-consuming to install. Copper waterlines will not corrode, but they are vulnerable to freesing, which causes them to burst.

Many older mobilehomes have the original polybutylene pipes, a flexible gray or black plastic waterline. Over time, the defective plastic fittings used to connect polybutylene tubing become brittle, crack and break. Polybutylene is no longer manufactured. Whenever plastic fittings are discovered, they should be removed. Brass or copper fittings, used with the new PEX waterlines are a suitable replacement. PEX provides the most resistance against corrosion and is extremely flexible, preventing the pipe from bursting under extreme conditions.

Most all homes have two sizes of waterlines -- 1/2 inch and 3/4 inch (inside diameter). 3/4 inch waterlines are generally used as the main waterline leading to and from the water heater. 1/2 inch is generally used everywhere else. The risers leading to the toilets or sinks are sometimes 3/8 or 1/4 inch.

PEX to Polybutylene:

Because so many manufactured homes still contain the gray polybutylene, repairs are still necessary. Since parts for old polybutylene systems are no longer available, repairs have to be made using PEX. There are adapter fittings available that connect old polybutylene pipes to new PEX pipes.

Installing New Waterlines:

When installing new PEX lines, you don't need to spend the extra time to remove the old waterlines--they can be left in place.

Manufactured homes are built to a HUD code. Homes built to a UBC or any other code have stricter plumbing requirements. In most areas PEX waterlines are acceptable but all fittings have to be accessible. In other words, connections cannot be made inside walls or underneath floors as they typically are in a manufactured home. For PEX to meet codes under those conditions, each waterline would need to be one long piece with no hidden fittings connecting additional pieces of waterline.