Polybutylene at a glance
- What it is
- Flexible plastic water supply pipe, most often gray, sometimes blue or black
- When it was used
- Widely installed in U.S. houses from roughly the late 1970s into the mid-1990s
- Usual marking
- Printed codes along the pipe, commonly PB2110
- Weak points
- Fittings and crimp joints, plus runs near the water heater
- Who can confirm it
- A licensed plumber, ideally one who has re-piped homes of this era
- Local relevance
- The oldest Highlands Ranch neighborhoods fall inside that window, though many houses have since been re-piped
Why a 1980s or early-1990s house raises the question
Highlands Ranch started building in the early 1980s and kept going for decades, which means the first several thousand houses were finished during the years when polybutylene was a normal, code-accepted choice for supply lines. Builders liked it because it was cheap, fast to install and flexible enough to snake through framing without many joints.
The trouble showed up later. Failures are commonly attributed to a combination of disinfectants in treated water slowly degrading the plastic and its fittings, and installation details such as crimp rings that were over- or under-tightened. A failing joint may weep for weeks behind drywall, or it may split under full line pressure and run until someone shuts the main.
Plenty of polybutylene systems are still holding after thirty-plus years. The difficulty is that nobody can tell you which fitting will be the one that lets go, or whether it will be in an unfinished furnace room or in the ceiling above a finished basement theater.
Telling supply pipe materials apart
| Material | Usual appearance | Typical markings | Where it often shows |
|---|---|---|---|
| Polybutylene | Dull gray flexible pipe, sometimes blue or black | PB2110 or similar codes | Water heater connections, unfinished basement ceilings, under sinks |
| PEX | Red, blue, white or gray flexible pipe with a slight sheen | The word PEX and standard ratings | Re-piped homes and newer construction |
| CPVC | Rigid cream or tan plastic with glued joints | CPVC and a size rating | Some homes from the 1980s onward |
| Copper | Rigid metal with soldered joints | Type letter such as M or L | Main lines, older or upgraded homes |
Places to look in a typical two-story with a basement
- Where the water line enters the house near the meter and main shutoff
- The hot and cold connections on top of the water heater
- Supply stubs under the kitchen sink and each bathroom vanity
- The open ceiling joists in an unfinished furnace or storage room
- Any tub or shower access panel on the back side of a wall
- The washer box in the laundry room
- Your purchase inspection report, which may name the pipe material
Questions for a licensed plumber
- Is the pipe inside my walls polybutylene, and what are the fittings made of?
- If the house was partly re-piped, which runs are still original?
- Would you replace the whole system or only certain sections, and why?
- How many drywall openings will the job need, and who patches and textures them?
- Does the work need a Douglas County permit and inspection?
- Until replacement happens, what should I check, and how should I use the main shutoff?
Common questions
- Will my homeowners insurer care that I have polybutylene?
- Some insurers ask about plumbing type when writing or renewing a policy, and practices vary between companies. Ask your agent directly whether the pipe affects your coverage or premium, and keep the answer in writing.
- If it has not leaked in thirty-five years, is it safe to leave?
- Age alone does not predict a failure, and many systems keep working. The real question is how much risk you are comfortable carrying above finished rooms. Knowing exactly where your main shutoff is reduces the damage if a fitting does give way.
General information for Highlands Ranch, not a quote or professional advice. In an emergency, call 911.