Key Takeaways
- Polybutylene was used in some homes built from the late 1970s to the mid-1990s.
- It's usually gray (sometimes blue or black) flexible pipe stamped "PB."
- Failures often happen at fittings, suddenly, with no warning.
- Replacing it with PEX or copper is the long-term fix.
What Is Polybutylene?
Polybutylene is a flexible plastic pipe that was widely used for water supply lines from the late 1970s into the mid-1990s because it was cheap and easy to install. Over time, it became known for failing: the pipe and its fittings can become brittle and crack, and the failures tend to happen suddenly.
Which Rockville, MD Homes Might Have It?
Homes and townhouses built or replumbed in that window are the ones to check, including many 1980s townhouse communities around Rockville. Newer neighborhoods like King Farm and Fallsgrove were mostly built after polybutylene fell out of use. Earlier homes such as those in Twinbrook may have it if they were partly replumbed during that period.
How to Identify Polybutylene
- Gray, sometimes blue or black, flexible plastic pipe
- Usually about 1/2" to 1" in diameter
- Often stamped with a "PB" code along the pipe
- Look where pipes enter the house, at the water heater, and under sinks
- Fittings may be plastic or copper crimp rings
Gray pipe at the water heater doesn't always mean polybutylene. PEX also comes in gray. Check the printed code on the pipe, or have us look during an inspection.
Why It's Worth Replacing
Unlike corroding metal pipe, polybutylene doesn't give much warning. A fitting can fail and flood a room while you're at work. Some insurers also ask about it. Replacing it on your schedule is much cheaper than repairing water damage after a failure.
What Replacement Looks Like
We replace polybutylene with PEX or copper, running new lines to every fixture with new shut-off valves, then pressure-test before closing the walls. Most homes take a few days. See repiping, or start with a plumbing inspection to confirm what you have.
We repipe homes across Rockville, Gaithersburg, Montgomery Village and Derwood, where homes from that era are common.
