Polybutylene is a gray, blue or black flexible plastic water pipe used in millions of U.S. homes built from about 1978 to 1995, often stamped PB2110. It can become brittle and crack from reactions with chlorine in treated water, and it tends to fail without warning. Because of that risk, many insurers and buyers treat it as a problem, and replacement with PEX or copper is usually recommended.
Polybutylene was marketed as the plumbing pipe of the future and installed in millions of homes from the late 1970s until 1995. Then it started failing. If your home was built or replumbed in that era, including many subdivisions around Greenwood, Center Grove and Whiteland, it’s worth checking what your water lines are made of. Here’s how to identify polybutylene, why it’s a risk, and what replacing it involves.
How to identify polybutylene
- Material: flexible plastic pipe
- Color: usually dull gray; sometimes blue or black
- Size: about ½ to 1 inch in diameter
- Markings: often stamped PB2110 along the pipe
- Fittings: plastic (acetal) or copper/aluminum crimp rings
- Era: homes built or replumbed from about 1978 to 1995
Where to look:
- Where the main line enters the house
- Near the water heater
- Under sinks and behind toilets (supply stubs)
- In an unfinished basement or crawl space
Gray pipe going into the house from outside may be polybutylene service line. Note: gray PEX exists too; PEX is marked “PEX,” not “PB.”
Why it fails
Polybutylene can react with oxidants such as chlorine in treated public water. Over time the inside of the pipe becomes brittle and cracks. Early plastic fittings also failed. The problem:
- Failures often come without warning
- They can happen inside walls and ceilings
- There’s no reliable way to predict which section will fail next
A class action settlement, Cox v. Shell Oil, in 1995 provided relief for some homeowners, and production stopped that year. That settlement has long since closed to new claims.
Insurance and home sales
Because of its failure history:
- Some insurers won’t write a policy on a home with polybutylene, charge more, or exclude related damage.
- Home inspectors typically flag it.
- Buyers and lenders may ask for replacement or a price reduction.
If you’re buying or selling a home from that era, identify the pipe early.
Replacement
Polybutylene replacement is done as a repipe, usually with PEX:
- National cost guides put a whole-house repipe at roughly $4,500 to $15,000, with PEX at the lower end. See whole house repipe cost.
- A polybutylene service line from the meter is a separate job. See water line replacement cost.
- Plan for drywall patching where walls and ceilings are opened.
If a polybutylene pipe is leaking now
- Shut off the main water. See how to shut off the water to your house.
- Have a plumber repair the failed section.
- Find any other hidden leaks. One failure is often a sign of more. Hidden water leak detection checks for leaks inside walls and ceilings without opening them all.
- Get quotes for a full repipe.
For a pipe that has already burst, see burst pipe: what to do.
Get it checked
We find hidden leaks in homes with older plumbing across Bargersville and Johnson County, including Greenwood, Center Grove and Whiteland.
Still can’t find it?
Our hidden water leak detection pinpoints the leak without tearing things up, so the repair starts in the right spot.
Frequently asked questions
How do I know if I have polybutylene pipes?
Look for flexible plastic pipe, usually dull gray (sometimes blue or black), about ½ to 1 inch across, often stamped PB2110. It's common near the water heater, under sinks and at the main line in homes built from about 1978 to 1995.
Why is polybutylene pipe a problem?
It can react with oxidants like chlorine in treated water, becoming brittle and cracking from the inside. Failures often happen without warning, sometimes at fittings.
Can I still get a claim from the polybutylene class action?
The Cox v. Shell settlement from 1995 has long since closed to new claims. Replacement today is at the homeowner's cost.
Will polybutylene affect my homeowners insurance?
It can. Some insurers decline to write policies on homes with polybutylene, charge more, or exclude related water damage. Ask your insurer directly.
How much does it cost to replace polybutylene pipes?
It's done as a repipe. National cost guides put a whole-house repipe at about $4,500 to $15,000, with PEX usually at the lower end.