Polybutylene pipes and home insurance in Michigan have become a real issue in our office. Polybutylene, the gray plastic plumbing used from the late 1970s to the mid-1990s, is showing up more often as an underwriting question when we quote homes, and that includes the short supply lines that feed toilets and sinks. If your home was built or replumbed in that window, it's worth knowing what you have before an insurer, an inspector or a leak tells you.
The short version: Look at the supply lines under your sinks and behind your toilets, and at any exposed pipe in the basement. If you see gray plastic pipe stamped "PB2110," have a plumber confirm it. Replacing the fixture supply lines is a small job; a whole-house repipe is bigger. Either way, document the work and send it to your agent.
What polybutylene is and why it fails
Polybutylene (PB) was a flexible plastic water pipe manufactured from 1978 to 1995, according to the home inspectors' association InterNACHI. It was cheap and easy to install, and it went into a lot of homes. It also failed. Disinfectants in public water, such as chlorine, react with the pipe and the plastic (acetal) fittings over time, and leaks most often show up at joints and fittings (manufacturers blamed improper installation). A failure tends to be a sudden leak or burst, often with little warning.
The national class-action settlement over PB pipe, Cox v. Shell Oil, was approved in 1995 with about $950 million in funding. Its claim deadline passed in 2009, so Michigan homeowners can no longer file a claim. Today, PB is a cost of ownership. It's also not on the list of approved water distribution materials in the Michigan Plumbing Code.
How to spot it, including at the sink and toilet
- Color. Usually gray, though PB also came in white, black, silver and blue (blue mostly for outdoor service lines). Some PEX and polyethylene pipe looks similar, so color alone isn't proof.
- Markings. PB is typically stamped "PB2110."
- Supply lines. Look under sinks and behind toilets. Older gray plastic supply lines (risers) running to a fixture can be polybutylene.
- Copper at the wall doesn't clear you. PB inside the walls was often connected to short copper stub-outs at the fixtures, so the part you can see may be copper while the pipe behind it isn't.
- Where it isn't. PB was used for water supply, not drains, so the white or black drain pipes under a sink aren't the concern.
If you're not sure, a plumber or home inspector can identify it in a few minutes.
Why insurers care
Water damage is one of the most common homeowners claims, and a material with a known failure history is an easy thing for an underwriter to flag. Some carriers decline homes with PB, some require it to be replaced, and some ask about it on the application. The answer varies by company.
Michigan's Essential Insurance Act allows a home insurer to base decisions on a home's physical condition, but the rule has to be objective, related to the perils insured, and based on a code, a manufacturer's specification or a similar standard, "without regard to the age of the structure" (MCL 500.2117). Practically, that means an insurer should be looking at what's actually in your house, not just the year it was built. Answer plumbing questions on an application accurately: in Michigan, a material misstatement on an application can give an insurer grounds to rescind the policy, even if the mistake was innocent.
If a PB line bursts, what does insurance pay?
- Sudden water damage is generally covered. A supply line that bursts and floods the bathroom is the classic covered water claim, subject to your deductible.
- The pipe itself usually isn't. Standard homeowners forms pay to tear out and replace the parts of the building needed to reach and repair the plumbing, but not for the failed pipe or fixture that leaked.
- Slow leaks often aren't. Many policies exclude seepage or leakage that continues "over a period of weeks, months or years" (some carriers use a fixed number of days), though ISO's form makes an exception for a leak hidden inside a wall, ceiling or floor that you didn't know about. Policy wording varies by carrier.
- The deductible matters. Many Michigan homeowners now carry $1,000 to $2,500 deductibles. A small leak under a vanity may not be worth a claim, and a claim on your record can affect your next policy; see will a claim raise your home insurance.
What to replace, and what it costs
Start with the fixture supply lines. Swapping gray plastic risers for new supply lines is a small job for a plumber and removes the most exposed connections in the house. Whatever you install, supply lines don't last forever: braided stainless lines have their own failure patterns, including corrosion from cleaning products stored under the sink and cracked plastic coupling nuts, so replace them on a schedule.
If PB runs through the walls, a whole-house repipe is the permanent fix. Angi's cost guide puts repiping between $1,500 and $15,000, with most homeowners around $7,500, depending on the size of the house and the pipe used. Keep the plumber's invoice; it's the document your agent needs to show an insurer the PB is gone.
Whether you replace it now or later, an automatic water shut-off valve or leak detector is cheap protection and can earn a discount with some carriers. See our post on water shut-off valves and leak detectors.
Frequently Asked Questions
Can I get homeowners insurance with polybutylene pipes in Michigan?
Often, but not with every company. Some carriers decline homes with polybutylene, some require replacement, and some write them as is. An independent agent can tell you which carriers will write your home and what they'll require.
How do I know if I have polybutylene supply lines?
Look under sinks and behind toilets for gray plastic supply lines, and check exposed pipe in the basement for a "PB2110" stamp. Copper stub-outs at the wall can hide PB behind them. A plumber or home inspector can confirm it.
Does homeowners insurance cover a burst polybutylene pipe?
Sudden water damage from a burst pipe is generally covered, minus your deductible, including tearing out walls or floors to reach the repair. The failed pipe itself usually isn't covered, and damage from a slow leak over time is commonly excluded unless it was hidden inside a wall, ceiling or floor and nobody knew about it, depending on the policy.
Can I still file a polybutylene class-action claim?
No. The Cox v. Shell Oil settlement's claim deadline passed in 2009. Replacing PB today is at the homeowner's expense.
Do I have to replace polybutylene pipes?
We're not aware of any Michigan law that requires you to tear out existing PB in your own home, but some insurers will, and a buyer's inspector will flag it. At minimum, replace polybutylene fixture supply lines, which is an inexpensive way to remove the most failure-prone connections.
The bottom line
Polybutylene is a known problem with a known fix. Find out whether you have it, replace the supply lines at least, keep the invoice, and make sure your insurer knows the work was done.
J. Jacobs & Associates is an independent agency in Lake Orion that has insured Michigan homes since 1981. We represent more than twenty carriers, so if your current company is asking about your plumbing, or your roof, we can find the companies that will write your home and what each one needs. Send us your declarations page and any plumbing invoices, or call (248) 693-6455. You can also start a homeowners quote online.