Gray Plastic Pipe in Your Charleston Home? What Polybutylene Means and When to Replace It

If you've ever looked under a sink, behind a water heater, or up in the attic of an older Charleston-area home and found gray plastic water lines, there's a good chance you're looking at polybutylene. We still find it in houses around Mount Pleasant, East Cooper, and the older neighborhoods off the peninsula. Neighbors usually ask us two things: is it really that bad, and do I have to replace it right now?

Here's the straight answer from Avery & Sons Plumbing + Tankless.

What polybutylene is

Polybutylene (you'll often hear it called "PB" or "poly") is a plastic water supply pipe that was installed in a lot of American homes from roughly 1978 through the mid-1990s. It was cheaper and easier to run than copper, so builders used it widely, including in mobile homes. A 1995 Los Angeles Times report put the number of housing units with it nationwide as high as 6 million.

Why it got a bad reputation

Polybutylene didn't fail because of one bad batch. Court records from the litigation describe chlorine in treated tap water, especially hot water, as a primary cause of the pipe and fittings breaking down. The damage starts on the inside, so the pipe can look fine from the outside right up until it cracks and leaks.

That led to a national class action, Cox v. Shell Oil, which settled in 1995. The Los Angeles Times reported the settlement at $950 million and called it the biggest property-damage settlement in the country at the time. One thing every homeowner should know: that settlement program is closed. The final filing deadlines ran out in 2009, so a polybutylene leak today is not covered by that fund. If it fails now, the cost falls on you and your homeowner's insurance.

How to tell if you have it

Here's what we look for when we walk a house:

• Color. It's most often gray. It also came in blue and black, so color alone isn't proof.

• Markings. Look for "PB2110" or "Qest" printed along the pipe.

• Where it shows up. Check where lines come out of the wall under sinks and toilets, at the water heater, and wherever the main enters the house. Those short stubs at the wall can be copper even if polybutylene runs behind the drywall, so look in the attic or crawlspace too.

• Fittings. Gray or white plastic insert fittings or copper and aluminum crimp rings are common on polybutylene systems.

Don't confuse it with PEX. Modern PEX is usually red, blue, white, or orange and is printed "PEX" on the side. It's a different material and it's what most houses get re-piped with today.

Do you have to replace it?

Not always overnight, but it should be on your list. Polybutylene that's been in a house for 30-plus years has already been exposed to decades of treated water, and there's no way to look at it from the outside and know how much life it has left. When it lets go, it's usually not a slow drip. It can be a burst inside a wall or ceiling, and in a two-story house on Daniel Island or in Mount Pleasant, that can mean drywall, flooring, and cabinets on two floors.

Some insurers and home inspectors flag polybutylene too, and it can come up when you're buying or selling. If you're getting ready to list your house, it's worth knowing before the buyer's inspector finds it.

What we recommend

If you've got polybutylene, the long-term fix is a re-pipe, usually with PEX or copper depending on the house. In the meantime, a few things help:

• Know where your main shutoff is and make sure it actually turns.

• Don't crank the pressure. If your home's water pressure runs high, a pressure-reducing valve takes stress off old lines.

• Keep an eye out for spots on ceilings, swelling at the base of cabinets, or a water bill that jumps for no reason.

• Consider a whole-house leak detector or automatic shutoff as a backstop until you re-pipe.

Not sure what's in your walls?

If you're in Charleston, Daniel Island, Mount Pleasant, or anywhere in East Cooper and want someone to take a look, give us a call at (843) 305-5555 or visit averysplumbing.com. We'll tell you straight what you've got and whether it can wait or needs attention now.

Avery & Sons Plumbing + Tankless