What is Polybutlylene?

Polybutylene is a form of plastic resin that was used extensively in the manufacture of water supply piping from 1978 until 1995. Due to the low cost of the material and ease of installation, polybutylene piping systems were viewed as “the pipe of the future” and were used as a substitute for traditional copper piping. It is most commonly found in the “Sun Belt” where residential construction was heavy through the 1980’s and early-to-mid 90’s, but it is also very common in the Mid Atlantic and Northwest Pacific states.

These are typically gray or white in color with a dull finish. Most are shown with pipe attached. Figure (4) is a new fitting.

The piping systems were used for underground water mains and as interior water distribution piping. Industry experts believe it was installed in at least 6 million homes, and some experts indicate it may have been used in as many as 10 million homes. Most probably, the piping was installed in about one in every four or five homes built during the years in which the pipe was manufactured.

How to Tell If You Have Poly Exterior – Polybutylene underground water mains are usually blue, but may be gray or black (do not confuse black poly with polyethelene pipe). It is usually 1/2″ or 1″ in diameter, and it may be found entering your home through the basement wall or floor, concrete slab or coming up through your crawlspace; frequently it enters the home near the water heater. Your main shutoff valve is attached to the end of the water main. Also, you should check at the water meter that is located at the street, near the city water main. It is wise to check at both ends of the pipe because we have found cases where copper pipe enters the home, and poly pipe is at the water meter. Obviously, both pipes were used and connected somewhere underground.

Interior – Polybutylene used inside your home can be found near the water heater, running across the ceiling in unfinished basements, and coming out of the walls to feed sinks and toilets. Warning: In some regions of the country plumbers used copper “stub outs” where the pipe exits a wall to feed a fixture, so seeing copper here does not mean that you do not have poly.

Will the Pipes Fail? While scientific evidence is scarce, it is believed that oxidants in the public water supplies, such as chlorine, react with the polybutylene piping and acetal fittings causing them to scale and flake and become brittle. Micro-fractures result, and the basic structural integrity of the system is reduced. Thus, the system becomes weak and may fail without warning causing damage to the building structure and personal property. It is believed that other factors may also contribute to the failure of polybutylene systems, such as improper installation, but it is virtually impossible to detect installation problems throughout an entire system.

Throughout the 1980’s lawsuits were filed complaining of allegedly defective manufacturing and defective installation causing hundreds of millions of dollars in damages. Although the manufacturers have never admitted that poly is defective, they have agreed to fund the Class Action settlement with an initial and minimum amount of $950 million. You’ll have to contact the appropriate settlement claim company to find out if you qualify under this settlement.

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“A series of reports have suggested that increased use of chloramines accelerates corrosion and degradation of some metals and elastomers common to distribution plumbing and appurtenances. With regard to elastomers, the study showed that with few exceptions, solutions of chloramines (either monochloramine or dichloramine) produced greater material swelling, deeper and more dense surface cracking, a more rapid loss of elasticity, and greater loss of tensile strength than equivalent concentrations of free chlorine.” —-Steven Reiber, HDR Engineering, American Water Works Association Research Foundation


Call Plumbing Express today for information and a firsthand look at what happens to the inside of poly pipes and fittings. We also offer free estimates within our standard service areas.

Polybutylene Pipes and Insert Fittings


Valves- Typically found under sinks and toilets.


Adapters- Typically used to connect polybutylene pipe to fixtures.


Other fittings.


Manufactured Manifolds.


A riser (22) is a pipe running from sink, toilet, or other fixture to a valve. Pipe may be white PVC (23), black polyethylene (24), cream CPVC (25), or gray polybutylene pipe marked “PB 2110 M” (26).

Polybutylene Plumbing System: Polybutylene pipe with plastic or metal fittings Polybutylene Yard Service Line: Polybutylene pipe utilizing any kind of fitting


These are typically gray or white in color with a dull finish. Most are shown with pipe attached. Figure (4) is a new fitting.


Metal Insert Fittings- These are typically made of copper or brass. New fittings are shown in (11, 12).


Polybutylene Pipe- Yard Service Line is typically blue (13), gray (14), or black (15). Inside Pipe is typically gray (14) or Black (15).

 How Do I Get Rid of Polybutylene? There are two types of poly replacement, Interior and Exterior. Exterior poly runs from the main street lines serviced by the city to your house. You are responsible for the portion from your home to the city hook up. And many of these underground lines were installed using poly. Interior poly lines run inside your home, behind your walls and under your floors. Following is information pertaining to how to replace both, Interior and Exterior poly. 

EXTERIOR: There are several factors that determine the process of replacing your underground water main. First, you must consider the depth underground. In the “Sun Belt” where the frost line is shallow, a trencher is used for excavation because it is economical for clients, and it causes very little damage to the landscaping. When a trencher is used, the entire job takes about six hours, and your yard will show very few signs of all the work that went into installing the water main. “Last Sunday my exterior polybutylene pipe broke. It caused a huge sink hole in the front yard and flooded my basement with about five inches of water.” —-Sabrina Greer, Germantown, Maryland In parts of the country where the frost line is deep, a device is pulled through the old line that splits it while simultaneously pulling new copper piping through the old, expanded line. For deep installations, this process is very economical and requires very little disturbance to your yard or interior. In a few instances, however, pulling the pipe is not feasible, a trench must be excavated. When this process is used, the excavated dirt is piled onto plastic sheeting to protect the landscaping, and demolition of interior concrete is usually limited to a small area which is draped-off with plastic to control dust. With either process, the yard and interior concrete is restored as necessary, and the work is completed in about six to twelve hours.

INTERIOR: The process begins by mapping out the existing plumbing system and then selectively cutting a limited number of holes in the walls.  Technicians strategically decide on where to make the least number of cuts to do the job right. If someone tells you they need to start ripping apart entire walls, escort them out of your home. And if someone tells you they can’t do the drywall themselves, you know you’re in trouble. Our experts provide you with a turnkey operation from plumbing to drywall to final restoration and computerized matching of your paint. In an average-sized home, 20-30 discreetly placed cuts are made. From these entry points brand-new copper plumbing is installed.

Our floors and walls were buckling and waterlogged.”“Cascading water ruptured the ceiling in several places on the main level and poured down onto [Milton and Rhonda Schultz’s] kitchen cabinets, newly decorated walls and oak floor. From there, it spilled into the living room and family room, destroying carpeting in its wake, and sloshed downstairs to the basement.” —-Kenneth Lelen, Washington Post, May 16, 1998