Polybutylene is a type of plastic resin. Shell Oil Company was the sole manufacturer of polybutylene resin used for plumbing applications. This material was used in the manufacture of interior and exterior water supply piping from 1978 until 1995. It is found most commonly in the South and was installed frequently in the Atlanta market. Estimates say that one out of every five homes built during these years has polybutylene plumbing. The polybutylene piping was used for two different applications in residential construction.

1. Exterior main water service lines connecting the home to the street
2. Interior plumbing systems

The interior and exterior piping material are independent of each other. Homes that have copper plumbing or PVC inside may have a main water service line made of polybutylene. While other homes may have a copper or PVC main line and have polybutylene piping inside, although this combination is less common than the former. Copper and PVC piping are the other materials that are used most frequently in our market. Copper is the most common and is often considered a superior product.

Benefits

• Low cost materials for economical plumbing system
• Easy to install
• Quiet plumbing system
• Functions well in cold temperatures

Potential Problems

Soon after polybutylene piping was used in residential homes, homeowners began reporting problems. The issue did not receive much attention until 1980, when lawsuits began to be filed.

While not proved conclusively, it is believed that chemicals found in the water supply, such as chlorine, react with the polybutylene piping and/or the acetate fittings causing them to become brittle. The plumbing system becomes weak and can fail without warning, causing damage to the home and personal property.

Determining if a home has Polybutylene Plumbing

There are several ways to determine if a house you are interested in buying has polybutylene plumbing systems. Class action lawsuits have been settled on this issue, a fact you should know if you own a house with this type of plumbing or if you are considering purchase of a home with this type of plumbing.

The home inspector should be able to identify polybutylene plumbing in a house that has captured your interest. You may also check the answer to question 7(h) on the Seller’s Property Disclosure Statement.

Often a visual check of the plumbing under the sinks will help determine the type of plumbing materials used. However, you should be aware that copper is sometimes used under the sinks and is then connected to polybutylene out of eyesight. The plumbing material in a home with an unfinished basement or a basement with a drop ceiling is easy to identify.

Occasionally the inspector will be unable to determine the material used for the main service line, since it is buried in the yard. A narrow trail or visible depression in the grass leading from the water meter may indicate that the line has been replaced. You may also want to notice other yards in the neighborhood, or talk with the neighbors. If neighbors have had replacement then the odds are that there was (or is) a polybutylene main service line to the home you are considering.