Guides · Plumbing

The gray pipe: how to tell if your house has polybutylene

Installed from about 1978 to the mid-1990s, it degrades from the inside where nobody can see it, and about one home in three in Washington County was built in the two decades it was on the market. The class-action money closed in 2009. Here is how to identify it yourself in ten minutes.

There is a plastic water pipe that went into American houses from roughly 1978 through the mid-1990s. It is usually gray. It was cheap, it was fast to install, and it was sold as the future of residential plumbing. Then it started failing, and the failures had a pattern nobody liked: they began on the inside of the pipe wall, where no inspection can see them, and they ended without much warning.

Most of what is written about polybutylene online is written by companies that want to repipe your house, which is a thing we also do. So here is the page written the other way round: how to check for yourself, what actually happens to it, what your insurer is likely to say, and the one question people ask that has a disappointing answer.

First: it is probably gray, and it probably says PB2110

Polybutylene is most often gray. It also came in blue and in black, and those two are more often the line running underground from the meter to the house than the pipe inside it. Color alone is not enough — there are other gray plastics in a plumbing system, and there is gray PEX.

The thing that settles it is the stamp. Polybutylene is marked PB2110. That is its ASTM cell classification, it is printed along the pipe, and it is the definitive marker. A gray plastic pipe with PB2110 on it is polybutylene. A gray plastic pipe without it is something else.

A drawing, not a photograph. We have not yet photographed polybutylene on one of our own jobs, and we would rather show you an accurate diagram than another company's picture.

Where to look, in the order that works

You do not need to open a wall. In most houses at least one run of pipe is visible somewhere, and it takes about ten minutes to check all of these.

At the water heater. The connections at the top are exposed in almost every house, and this is where most people find it.
At the main shut-off, wherever your water comes into the house — a garage wall, a utility closet, a crawlspace.
Under the kitchen and bathroom sinks, and behind the toilet, at the little shut-off valves called stops.
Where the service line enters the building at the meter. This is where the blue or black version turns up.
In a slab home where the plumbing was run overhead, at the ceiling stub-outs in a garage or unfinished space.

The fittings are the part that actually fails

This is the detail most articles skip, and it changes what you are looking for. The early systems used acetal insert fittings — a plastic fitting, often sold under the name Celcon — held on with aluminum or copper crimp rings. Later systems used copper insert fittings instead.

The acetal fittings and the aluminum rings were the dominant failure point, more so than the pipe itself. If you find gray pipe joined by white or off-white plastic fittings with a metal band crimped over them, you have found the combination the whole class action was about.

It is also why a house can have polybutylene and no history of leaks, and a neighbor's identical house can have had three. The pipe is the same. The fittings and the water were not.

Why it fails, and why you cannot see it coming

Chlorine and chlorine dioxide in treated water oxidise the material. The result is micro-cracking, flaking of the inner wall, and embrittlement. The failure concentrates at stress points — fittings and bends — and it can result in the pipe bursting with little warning.

The important part for a homeowner is the direction of travel. The degradation starts on the inside of the pipe wall and works outward. Looking at the outside of a polybutylene line tells you almost nothing about how much of it is left. A pipe that looks perfectly sound can be most of the way through its wall.

The acetal fittings go the same way. The oxidising disinfectant reacts with the acetal, which scales, flakes and becomes brittle, until the fitting stops holding.

What this has to do with St. George specifically

St. George disinfects its water with free chlorine rather than chloramine. The 2024 water quality report puts the measured chlorine residual between 0.10 and 1.19 parts per million.

Chlorine is the agent implicated in polybutylene failure. So any polybutylene still in service in this city is sitting in continuously chlorinated water, and has been for its whole life. That is a statement about exposure, not a prediction about your particular house — but it is the reason this is not a problem that is going to quietly resolve itself here.

The part the local plumbing ads get backwards

The usual line about housing here is that almost nothing is old — only about three percent of Washington County homes were built before 1970. That is true, and it gets used to suggest this is a market with no legacy plumbing problems.

Polybutylene is not an old-house problem. Look at when the county actually got built:

Washington County housing units by year built. US Census Bureau, American Community Survey 2024 1-year, Table B25034.
Built	Housing units
2020 or later	12,052
2010 to 2019	19,036
2000 to 2009	20,966
1990 to 1999	19,217
1980 to 1989	9,531
1970 to 1979	4,931
1969 or earlier	2,682
Total	88,415

About one house in three is from the right decades

Add the two middle rows: 28,748 of Washington County's 88,415 housing units were built in the 1980s and 1990s. That is 32.5 percent, about one in three, and those are the two decades polybutylene was on the market.

Be careful with that number, because we are going to be careful with it. It does not mean 28,748 houses here have polybutylene. Most of them do not. Polybutylene was one product competing against copper, and plenty of houses from those years were plumbed in copper by builders who never touched the stuff. The number tells you the size of the cohort worth checking, not the size of the problem.

But it does mean the instinct is wrong. Your 1993 St. George house is too new for a clay sewer line and exactly the right age for polybutylene.

Found gray pipe with PB2110 on it? Send us a photograph and we will tell you what it is.

Call (801) 680-6859 Ask for a visit

What your insurer is likely to say

Two different things get confused here, and the difference is worth real money.

A standard homeowners policy responds to sudden and accidental water damage. If a polybutylene fitting lets go at two in the morning and soaks a floor, that damage is normally the kind of thing the policy exists for. The cost of replacing the pipe that did it is a different category: that is maintenance, and maintenance is not what a homeowners policy is for. So the burst may be covered while the repipe that prevents the next one is not.

Separately, and this is the part people hear about: carriers commonly decline to write or renew a policy on a house with live polybutylene supply lines, and some require replacement as a condition of cover. How common, and on what terms, varies by carrier.

We are not going to tell you what your insurer will do, because we do not know and neither does anyone else writing about this. Ask them directly, and ask them to put the answer in writing. That written answer is worth having before you decide anything, and it is free.

The disappointing answer: the settlement money is gone

Nearly everyone who learns they have polybutylene finds their way to the class action, and it was a real one. Cox v. Shell Oil, in Tennessee state court, covered owners of property where polybutylene with acetal insert fittings was installed between 1 January 1978 and 31 July 1995. The court approved it in November 1995 with an initial commitment of $950 million from Shell and Hoechst Celanese. Class counsel report that more than 320,000 homes were completely re-plumbed at no cost to the owner and that more than $1.14 billion was ultimately spent, most of it going straight to homeowner relief.

It was administered by an organization called the Consumer Plumbing Recovery Center. And it is over.

All claims had to be filed by 1 May 2009. The program closed. There is no fund, no successor fund, and no current route to recover the cost of a repipe from Shell or from anyone else. If a page you are reading is vague about this, or hints that you might still be entitled to something, that vagueness is doing work for somebody and it is not you.

We would rather tell you the money is gone on the page than let you find out after a phone call.

Why fixing the leak does not fix the problem

The instinct after one failure is to repair that failure. With most plumbing materials that is the right instinct.

It is the wrong one here, because the material and the fittings are degrading everywhere at once and at roughly the same rate. The joint that let go was not unlucky; it was first. Repairing it changes nothing about the twenty others in the same house that have had the same water in them for the same thirty years.

The published position on this is blunt: the only long-term solution is to completely replace the polybutylene plumbing throughout the entire building. That is why spot repairs on polybutylene turn into a treadmill, and why we will tell you when we think you are on one.

What a replacement actually involves

A repipe replaces the supply lines through the house. It does not touch your drains, which are a different material and a different problem.

The work is mostly about access, not plumbing. New lines get routed through walls, ceilings and attics; there are openings cut to reach the runs; and then there is drywall repair and paint, which on most jobs is a larger share of the time than the pipe. A house is generally liveable through it, with water off for part of each working day rather than all of it.

The things to pin down before anyone starts, and to have in writing: what happens to the walls and who repairs them, whether the price includes paint, how many days you will be without water and when, whether a permit is being pulled, and what happens to the old pipe left in the walls, which is normally abandoned in place rather than dug out.

We do not publish a price for this, here or anywhere. Every one of these jobs is priced on the house, and a number on a web page for work this variable would be a number we could not hold.

If you find it, in what order to act

Photograph the pipe and the stamp. You will need the picture for the insurance conversation and for any quote.
Ask your carrier, in writing, what they do about polybutylene at renewal. Do this before you get quotes, because the answer changes how urgent this is.
Find out whether it is all of the house or part. Some houses were partly repiped years ago and nobody wrote it down.
Get the work quoted as a whole-house repipe, with the wall repair spelled out, not as a per-leak repair.
Do not let anyone tell you the settlement might still pay for it.

What we’d do at your house

We look at the pipe and tell you what it is, and if it is not polybutylene we say so and leave. Gray plastic is not automatically the expensive answer, and we would rather lose the job than sell a repipe to a house with PEX in it.

If it is polybutylene, you get a written scope: which runs, how many days, what happens to the walls, whether we are pulling a permit, and one number that does not change based on what we find behind the drywall.

You get photographs of the stamp and of the fittings, so you have something to send your insurer that is not our word for it.

If only part of the house has it, we will tell you that too, and price the part.