What Is Polybutylene Pipe? (How To Identify, Cost, Lawsuits, Pictures)

🕖Last Updated On December 28, 2021

Polybutylene is a plastic resin that was used to make a pressurized water pipe from 1978 to 1995. It is estimated that polybutylene piping was installed in over 10 million homes around the United States during this period until it was banned.

Building codes across the U.S. and Canada have long outlawed the installation of polybutylene pipes for new construction.

It was discovered that chlorine and other disinfectants used in public water made polybutylene pipe brittle and prone to fracturing. Homeowners have experienced small leaks (around the pipe fittings) while others have suffered catastrophic plumbing failures.

In this guide, I will go over things like…

  • How to identify polybutylene plumbing
  • The cost to replace polybutylene pipe (and whether you should)
  • What is the likelihood of pipe failure?
  • Major changes to how it was installed
  • And pictures of polybutylene piping

You can skip ahead and see pictures of polybutylene piping right here.

Where Was It Installed?

Search traffic for ‘polybutylene’ across the U.S. (source: google trends)

The installation of polybutylene piping between 1978 and 1995 is far-reaching across America. But there are three regions of the United States with the highest concentration of PB piping:

  1. Mid-Atlantic: New York, New Jersey, Maryland, Virginia
  2. Pacific Northwest: Washington, Oregon, Idaho
  3. Sunbelt: Florida, Georgia, North Carolina, South Carolina

Read Also: Home Inspection Checklist For Buyers

How To Identify It?

It is very easy to identify polybutylene pipe if you know what to look for. PB piping is usually a gray, blue, black, or white, and it is only used for supply distribution piping — it isn’t used for drain, waste, or venting. There is always a marking of PB2110 on the pipe to 100% identify it. Here are a few things to look for:


Polybutylene usually has a gray color, but it can also come in blue, silver, white, or black — one region of the country typically has the same color. In my neck of the woods of Virginia, poly piping always has grayish blue appearance.


A surefire way of identifying polybutylene plumbing is to look for the PB2110 mark stamped somewhere on the pipe. You may also see the brand names of Qest or ‘Bow Super-Flex’ on the pipe.

polybutylene qest pb2210
PB2110 marking on polybutylene pipe

Don’t Confuse With PEX, CPVC, or PVC

Another way to identify poly is to make sure it isn’t some other type of common pipe. Besides copper piping (which is easy to identify) — you don’t want to confuse poly with other plastic piping such as PEX, CPVC, or PVC which are very common plastic water pipes.

Poly Identification (1)
Gray blue color of polybutylene pipe

PEX piping is usually red (for hot water) and blue (for cold water), but it can also be different colors and even clear-colored. PEX is also stamped with “PEX” somewhere along the pipe.

CPVC is a cream colored pipe with a yellow stripe along it’s length which is very common in newer homes due to the high cost of copper. PVC (a common white pipe) is only used for drain, waste, and vent piping and is not used for potable water. Polybutylene was never used as drain piping.

Interior Locations of Poly Piping

If you are looking for polybutylene piping on the inside of a home, I would first check the bathrooms and kitchen. Look for the water pipes that come out of the walls to feed the sink and toilets.

You want to be careful of the possibility of copper stub outs. These are short pieces of pipe that connects to the fixture, but inside the wall there is hidden PB pipe.

I recommend going into the basement to look for the pipes in the ceiling if it is an unfinished basement. If it is finished, check the utility room. You should see the water pipes that are feeding the water heater, utility sink, and washing machine.

Inspect The Main Water Line

The main water line is also usually in the utility room, so you should check if this pipe is polybutylene as well. The main water line is typically 3/4-inch to 1-inch in diameter. Replacing the main water line can be almost as expensive as changing the home’s interior plumbing.

Even if I don’t see polybutylene inside the home for the main water line, I recommend still checking the water meter at the street. There may be a connection between polybutylene and non-poly somewhere in the front yard. The poly pipe section may only be visible if you open up the water meter lid.

It is also important not to confuse the main water line with a different material. Poly piping used for main water lines has an strong blue color. If the pipe is black, it is almost certainly HDPE or high density polyethylene. In my area, all homes either have copper, HDPE (black color), or polybutylene (blue color) as the main water line.

Poly Main Water Line
Main water line is a blue color. Very expensive to replace.

Read Also: How To Pass A Home Inspection?

Will The Pipes Fail?

Unfortunately, it is impossible to know how, where, or when your home will leak if it has polybutylene pipe. Some homes have had polybutylene for decades without any problems. Other homes may get just a few small leaks, while other homes can have catastrophic pipe failures with serious flooding damage.

Most homeowners only replace the home’s piping after getting leaks or if they are selling the home — and the home inspector reports it.

You may also have piping leaks inside of your walls and not even realize it. Hidden pipe leaks can result in wood damage and mold growth for years behind the wall and ceiling cavities.

Chlorine Damage

The most cited reason for polybutylene pipe leaks has been blamed on disinfectants in the public water supply such as chlorine. Researchers have determined that polybutylene pipe deteriorates in the presence of chlorine. When poly pipe was introduced in the late 1980’s, we simply did not know how this pipe would stand up to chlorinated water.

Currently, we have advanced testing standards for the structural strength of plastic piping such as PEX and CPVC in the presence of chlorinated water that polybutylene pipe was not subjected to in the 1970’s.

Other Reasons For Failure

Some of the other causes for PB pipe leaks have been attributed to improper installation, defective manufacturing, and just poor design. It is impossible to determine improper installation in the entire plumbing system.

Location of Leaks

Unfortunately, it is impossible to know exactly where future polybutylene pipe leaks will occur because it is an largely an invisible process. The small cracks and flaking occur on the interior of the water piping, and these cracks eventually work their way outwards where the leaks finally appear. These leaks can occur gradually and slowly, or they can happen suddenly with a burst pipe and water damage.

Increase In Water Bill

If you have a home with PB pipe, and you notice a steady increase in your water usage or bill — you may have hidden leaks behind your walls and ceilings. It would be advisable to open up some exploratory holes or to use a moisture meter to try and find the possible leaks.

Read Also: 10 Home Inspection Tips For Sellers

Class Action Lawsuits

Individual lawsuits began flying from homeowners in the early 1980’s against builders and local cities — mostly in Texas and California. But the major class-action lawsuits happened later in the 1990’s such as…

  1. Spencer v. DuPont
  2. Cox v. Shell.

Shell and DuPont were two of the largest manufacturers of polybutylene plumbing. They both settled with the courts and have agreed to fund a settlement that has totaled over one billion dollars.

The main difference between the two settlements is that for Spencer v. DuPont, homeowners were only reimbursed for up to 10% of the cost to repipe their homes.

The Cox v. Shell settlement covered 100% of the replumbing costs for homeowners with polybutylene plumbing. Currently, both of these settlement funds have long been depleted, and homeowners with polybutylene pipe are on their own.

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What Is The Cost To Replace?

Virtually all licensed plumbers will recommend replacing polybutylene piping with either PEX, CPVC, or copper. Even if there aren’t any visible and current leaks, replacing PB piping is frequently recommended to homeowners to prevent a future disaster.

Leaks inside of the ceilings and walls can cause significant flooding damage to a home and possible mold growth. A ruptured main water line may cause serious foundation movement and damage.

It is important to note that various building codes across the country have banned polybutylene piping since the 1990’s. However, if your home has PB piping, it almost certainly has grandfathered status and isn’t a current code violation.

You can expect to pay between $3,000 to $10,000 to replace polybutylene piping with PEX or CPVC. You will likely pay much more to replace it with copper.

And don’t forget the main water line if it is polybutylene as well. For a main water line to the street, you can also expect to pay between $2,500 to $7,500 depending on the length and depth of the pipe.

Most of the cost to replumb the home is not in the pipe itself but in the labor. Having to remove and replace drywall is very labor intensive.

Get At Least 3 Quotes

If you are considering replacing your home’s piping, I recommend you get at least 3 quotes in writing from licensed repiping companies. Professional repiping plumbers specialize in replacing (replumbing) polybutylene pipe. If you try to get a quote from a traditional plumber, the cost may be significantly more.

Why Was It Installed?

Poly was originally made under the brand name Qest, and it was marketed to builders as a much cheaper alternative to copper piping. As far as builders knew, poly piping was a great material, approved by building codes, and it had excellent resistance to freezing temperatures.

Very Easy To Install

Not only was poly significantly cheaper than copper, it could shave days or even weeks off from a whole house plumbing installation; a very big advantage for builders.

Rather than being soldered together like in copper (or glued together as in CPVC), poly was fastened together by using compression bands called “crimping”. Modern PEX piping still uses this compression/crimping style of installation. PB pipe was also much lighter than copper, so it was easier to carry to the job site.

At the time, poly manufacturers told builders and plumbers that it had a lifetime expectancy of 50 years, which we later found out to be far from the truth. On average, it only took about 12 years for problems with leaking poly pipes to show up.

Read Also: 7 Things That Fail A Home Inspection

History of Plumbing Changes

In the early years of polybutylene pipe installations, the majority of leaks happened at the PB fittings. It was theorized that these leaks were mainly due to improper installation, exposure to UV light, improper storage, bad water chemistry, and other issues. This lead to changes to how it was installed to try and solve the problems being reported with poly pipe.

There were three main developments with polybutylene pipe…

1. Aluminum Compression Rings

In the early years of poly, the pipes were connected with numerous acetal (plastic) fittings that were usually the same color as the poly piping. The very first plastic fittings were compression-type fittings also known as “grip” fittings. Later on, plastic fittings were crimped to the poly pipes using aluminum rings.

There were approximately 10-20 plastic fittings from one plumbing fixture to the main water line; many possible points of failure.

2. Metal Fittings And Copper Compression Rings

The next development occurred when plumbers scrapped the problematic plastic fittings in favor of copper (or brass) fittings with copper compression rings. If you have this polybutylene pipe system installed in your home, it is known as the “least bad” type of PB pipe installation. This greatly reduced the problem of leaks at the fittings — at least for a while.

Copper Fittings With Copper Rings (Polybutylene)
Polybutylene pipe copper fittings with copper compression bands.

Unfortunately, leaks kept occurring, and polybutylene pipe lawsuits were brewing. A study at the University of Illinois has shown that microfractures can occur at any point of the water pipe leading to ruptures potentially anywhere. Nevertheless, polybutylene plumbing went one step further in development…

3. The Manifold Or “Home Run” Poly System

The manifold was also an improvement on the polybutylene piping system. The manifold or home run system simply means that there is a central location or “manifold” where every plumbing fixture directly connects to it.

So each plumbing fixture is isolated and doesn’t share water piping with any other fixtures. Modern PEX piping still commonly uses the manifold type of system.

polybutylene manifold (2)
Manifold system was used later on.

This means that there are fewer fittings needed for each plumbing fixture. Without the manifold system, there would be about 20 fittings just for one plumbing fixture. By using the manifold, the number of fittings was per fixture reduced to just a few.

With fewer fittings, it meant less opportunity for leaks at the joints. In addition, the manifold could be easily monitored for leaking — a central area where the fittings are located.


Here are some pictures of polybutylene plumbing from numerous home inspections in the VA, MD, DC region…

sharkbite polybutylene to copper
Copper to polybutylene (blue) connection
grip polybutylene connection
Old grip fittings used in the early years of polybutylene plumbing
Acetal Fittings With Aluminum Rings (Polybutylene)
Aluminum compression rings with acetal fittings
polybutylene copper bands
Copper fittings with copper compression bands. The ‘least worst’ type of poly piping installation.
Poly Manifold System
Manifold system with copper fittings. “Least worst” installation of poly piping.
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15 thoughts on “What Is Polybutylene Pipe? (How To Identify, Cost, Lawsuits, Pictures)”

  1. I have samples of Poly B tubing that came from my boiler system (!) that are 30 years old. The pipe has no fissues, fractures, or signs of decay. It had some scale inside due to the rust from the boiler, but it was easily cleaned with some X400. Do you know who makes the most money from PB Pipe lies? Plumbers and lawyers. Don’t believe the hype. 99% of this mess was using the wrong compression fittings. The rest is all about fear and money.

    • Congratulations on your find. I think you missed one of the main points listed under the section “What is Poylbutylene?” As mentioned in that part, I also believe you don’t have the equipment to view those fractures. Just a thought.

    • Hi Marcelo,

      Poly piping is only used for supply piping and not drain piping so I wouldn’t worry about it. But yes, I think it theoretically could be have an impact if the drain piping was poly and pouring bleach down the drain was a consistent thing.


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