Key takeaways
- Polybutylene (PB) was used for buried service lines from roughly 1978 to 1995, which lines up exactly with Kitsap's post-mall subdivision boom.
- It degrades from the inside when exposed to chlorinated water and fails by splitting along the pipe, often with no warning.
- Gray flexible pipe at the meter or the point of entry, sometimes stamped PB2110, is the tell.
- Because the whole line is the same age and material, a spot repair leaves the same failure waiting everywhere else.
What polybutylene is
Polybutylene is a flexible gray plastic pipe that was sold as a cheaper, easier alternative to copper from the late 1970s through the mid 1990s. It was used both inside houses and, in a larger-diameter form, for buried water service lines from the meter to the house. It was pulled from the market after widespread failures and a national class action settlement in the mid 1990s. By then an enormous amount of it was in the ground, including under a large share of the homes built in Silverdale, Port Orchard, Kingston, Poulsbo and South Kitsap during the 1980s building boom.
Why it fails
Chlorine and other oxidants in treated water react with the pipe material over time, making it brittle from the inside out. The outside of the pipe can look fine while the inside has developed micro-fractures. Eventually the pipe splits along its length, usually with no warning and often at a point of stress: a bend, a spot where a rock presses on it, or near a fitting. The fittings themselves, originally acetal plastic, also crack. Buried polybutylene is typically thirty to forty-five years old in Kitsap now, and failures are routine.
How to tell if you have it
Look at the pipe where it enters the house, in the crawlspace or utility room, and at the meter box if the pipe is visible there. Polybutylene service pipe is gray, flexible, and often stamped with PB2110 along its length. It may be connected with brass or copper insert fittings and crimp rings, or with the original plastic fittings. Blue or black flexible pipe is polyethylene or PEX, not polybutylene. If the house was built between about 1978 and 1995 and the pipe is gray, assume PB.
Repair or replace
When a polybutylene line splits, it can be cut and coupled like any other pipe, and sometimes that's the right call to get the water back on tonight. But the whole run is the same age and the same degraded material, and the next split is already developing. Our standard recommendation when we expose polybutylene is a continuous replacement in PEX or HDPE from the meter to the house, which on most Kitsap subdivision lots is a one-day job. We'll make the temporary repair if that's what's needed, and we'll be honest that it's temporary.
The Kitsap connection
Silverdale's Ridgetop, Island Lake and Bucklin Hill neighborhoods, Port Orchard's 1980s hillside developments, the Kingston and Poulsbo subdivisions off Highway 104 and Viking Way, and much of unincorporated South and Central Kitsap were built in exactly the polybutylene years. If you own a home from that era and have never replaced the service line, a high bill or a pressure drop is worth a locate before it becomes a flooded crawlspace.
Written by the crew at 360 Leak Finders
We locate, excavate and repair buried water lines and exterior drains across Kitsap County, 24 hours a day. If this guide raised a question about your property, call (206) 354-9906.