How to spot polybutylene pipes in Charlotte homes and what to do

By the Alpha Drain teamPublished November 14, 20266 min read

What is polybutylene pipe and when was it installed?

Polybutylene, often shortened to PB or poly, is a flexible plastic water supply pipe. Builders used it in place of copper in a great many homes. InterNACHI, the International Association of Certified Home Inspectors, dates its use in home plumbing from 1978 to the mid-1990s and estimates it went into as many as 10 million U.S. homes.

It was run inside houses for hot and cold lines and outside for the buried line from the water meter. If your Charlotte-area house, townhome or condo was built or replumbed in that window, it is worth ten minutes to check.

How do I know if my house has polybutylene pipes?

Look at exposed pipe in these places:

• In the crawlspace or basement, running along the floor joists
• At the water heater, on the lines coming off the top
• Under sinks and behind toilets, where the supply comes out of the wall
• At the main shutoff valve and where the water line enters the house
• At the water meter

Polybutylene has four giveaways:

• Color. Usually gray. It was also made in blue, black, white and silver. Blue was used mostly for cold water lines outdoors.
• Flexibility. It bends in gentle curves instead of running in rigid straight lengths with glued elbows.
• Size. Half an inch to one inch across.
• Markings. The code PB2110 is usually printed along the pipe. This is the most reliable sign.

Do not stop at the first pipe you see. Some homes have copper stubs at the fixtures with polybutylene behind the wall, so a copper pipe under the sink does not rule it out. The crawlspace tells the real story. Other pipes also get mistaken for it:

Why does polybutylene pipe fail?

The commonly cited cause is the water itself. InterNACHI points to research showing that disinfectants in treated water can react with polybutylene and cause it to flake apart. Charlotte Water adds chlorine to control bacteria, as public utilities do, so pipe here has spent its whole life in those conditions. Manufacturers have maintained that most leaks happen at joints and fittings.

Two things make it hard to manage. The damage starts on the inner wall, so a pipe can look sound from the outside until it splits. And there is no practical field test. Checking the inside means shutting off the water and taking the system apart.

It is also fair to say that not every polybutylene system has failed. When the North Carolina Real Estate Commission studied the issue, it concluded that most of this piping does not commonly fail. The trouble is that nobody can tell you which house is next.

Does polybutylene affect insurance or selling a home in North Carolina?

It can affect both. This is general information, not legal or insurance advice.

• Insurance. InterNACHI warns that owners of homes with polybutylene may face higher premiums or be denied coverage. Rules differ by company, so call yours and ask how they treat it.
• Disclosure. North Carolina's Residential Property and Owners' Association Disclosure Statement asks sellers what the dwelling's water pipes are made of, and polybutylene is one of the boxes.
• Material fact. The North Carolina Real Estate Commission's position is that the presence of polybutylene alone is not a material fact. It becomes one when an agent knows, or should know, of a probable defect, such as past leaks in the home or failures in neighboring units.
• Buyers. The Commission suggests that buyer's agents advise clients to talk to their insurer before making an offer. InterNACHI adds that polybutylene can lower a home's value or lengthen its time on the market.

If you are buying, find out during due diligence. A plumbing inspection identifies the supply pipe material throughout the house, including the crawlspace, while you can still negotiate.

What should I do if I find polybutylene in my home?

1. Do not panic. It is a known risk to plan around, not a reason to move out tonight.
2. Find your main water shutoff and make sure everyone in the house can close it. If a line splits, that valve decides how much damage you get.
3. Check for leaks now. Look under sinks, around the water heater and through the crawlspace for drips, stains and green or white crust on fittings. A water meter that moves with every fixture off means water is escaping somewhere.
4. Call your insurer and ask whether your policy has any polybutylene restrictions.
5. Fix leaks properly. A plumbing repair can cut out a failed section and replace it with modern pipe and the correct transition fittings. That stops the leak. It does not make the rest of the pipe any younger.
6. Plan for replacement. A full repipe swaps the polybutylene for modern pipe such as PEX or copper. The cost depends on the size of the house, the number of bathrooms and how the pipes are reached, so get a written quote from someone who has seen the house.

Alpha Drain finds and repairs leaks in Charlotte homes, including failed polybutylene sections, and can talk through replacement with you. Spyro has 15 years of experience, repairs carry a 1-year labor warranty, and you get the price before work starts. For an active leak, shut off the main and call our emergency plumber line at (980) 408-1705, any hour. For a second opinion on what is under your house, see leak detection or send us a message.

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Written by the Alpha Drain team in Charlotte, NC. Alpha Drain is a licensed and insured plumbing company run by Spyro Vassiliou, a plumber with 15 years of experience. This article is general information, not a substitute for an on-site diagnosis.