The truth about polybutylene piping

Feb 18

Written By PK - Daylight Home Inspections

Describing and inspecting plumbing materials during a home inspection

Home inspectors are required to describe the plumbing supply and distribution piping materials as part of a home inspection in British Columbia (and for the most part, throughout North America). They are also required to visually inspect the plumbing system. These are important items in many home inspection associations’ standards of practice because they can provide clues about the expected performance of the plumbing materials and system.

7. PLUMBING SYSTEMS
7.1 The inspector shall:
A. inspect:
1. interior water supply and distribution systems including all fixtures and faucets.
B. describe:
1. water supply, distribution, drain, waste, and vent piping materials.

As home inspectors with experience inspecting all kinds of homes throughout the Okanagan, we see a variety of plumbing materials, and the type that brings about the most questions is the grey plastic piping called polybutylene. Although it’s not possible for a home inspector to determine if and when a polybutylene plumbing system will leak, they can look for underlying and specific conditions, like visible repairs, that may or may not promote longevity. It’s the duty of a home inspector to share notable information about the home with their client, and if polybutylene is present in the home, it’s definitely something worth learning more about.

History of polybutylene piping

Polybutylene (also known as Poly B) is the first generation of flexible plastic that was commonly used in the manufacture of water supply piping from the early 1970s until about 1995. For over a decade, polybutylene piping was viewed as a great residential plumbing material, and an alternative to copper piping, due to it being very inexpensive to produce and easy for plumbers to install. Plumbers loved working with it because the plastic piping is much more flexible than traditional copper piping, having some definite bend to it. This flexibility allowed installers to work quickly and efficiently without having to make precise measurements, cuts, and connections. Plastic is also lighter than metal so workers found the piping easier to transport.

Polybutylene was first tested and certified by the CSA (Canadian Standards Association) for use in potable water systems. Polybutylene piping is found all over North America, especially in areas—like British Columbia—where residential construction was heavy through the 1980's and early-to-mid 90's. Burnaby, Coquitlam and Port Coquitlam, as well as Kelowna, and Penticton are cities in BC that have large pockets of homes—sometimes entire neighbourhoods—that have polybutylene piping. In the mid-1980s insurance companies noticed a pattern of leaks emerging in homes with polybutylene piping. By 1995 most tradespeople stopped using the material in residential construction. In 1997 Poly B was banned by the National Plumbing Code, which oversaw plumbing trades in Canada. In 2005, the NRC-CNRC National Plumbing Code (and the Government of Canada) officially removed Poly B from the list of acceptable plumbing piping materials. That’s why in the Okanagan, typically only homes built between 1978 and 1995 have polybutylene piping in them.

Polybutylene pipes in a Kelowna utility room

How to identify polybutylene

Polybutylene pipes are typically grey in colour with a dull, matte finish. On occasion polybutylene pipes can be white in colour. The most common diameter is 1/2” or 3/4”—the same as most residential copper piping.

Polybutylene piping systems were used for underground water mains and in residential homes as interior distribution piping. Plumbers and industry experts estimate that polybutylene was installed in between 6 and 10 million homes throughout North America, and upwards of 650,000 - 750,000 homes in Canada alone! The piping was installed in about 20-25% of new homes built during the years in which the pipe was manufactured.

How to tell if your home has polybutylene?

Inside Your Home - Look near your hot water tank, running across the ceiling in your utility room, crawlspace, or unfinished basement, under your kitchen sink, and penetrating walls to supply sinks and toilets.

Outside Your Home - Polybutylene water mains are usually grey, blue or black. (Note: black polybutylene can look similar to polyethelene pipe). Service piping is usually 1" in diameter, and it may be found entering your home through a penetration in the concrete slab (either floor or wall in the basement or crawlspace). (Tip: The water main usually enters the home near the water heater, right before your main shutoff valve).

If you are in Canada, you can look for the common piping manufacturer’s stamps, or identifying codes, on the pipes:

“POLY” or “POLY-B”
“PB2110”
“B 137.8” or “CSA B 137.8"
“ASTM”, “D3309” or “ASTM D-3309”
“QEST”
“SDR11” or “SDR-11”
“POTABLE” (This word stamped on the pipe validates the safety the piping for drinking water)
“MIN 690 kPa @ 82C” or “100 psi @ 180F” (Pressure rating)

Note: The absence of these codes doesn’t necessarily mean the plumbing is not polybutylene. If the plumbing material meets all the other criteria, it could still be polybutylene.

Will poly b pipes always leak?

Many people believe that oxidants in water supplies—and chemicals such as chlorine—react with polybutylene pipes and their fittings, slowly degrading the plastic, making it brittle. Different cites and different municipalities have different minerals in their water supplies, and some are more strenuous on piping materials than others. Tiny cracks form inside the plastic pipes, and the structural integrity of the pipes is reduced. The pipes can fail without warning causing pinhole leaks, which can damage to the structure and belongings. Other factors such as poor installation can certainly contribute to the failure of polybutylene systems, but it’s nearly impossible to detect installation problems in a home when most of the plumbing system is concealed behind walls, ceilings, and floors.

In the early 1980s homes with polybutylene began to spring pinhole leaks—these are tiny leaks that aren’t always obvious until they’ve caused significant damage in walls and ceilings. Many lawsuits were filed complaining of allegedly defective manufacturing and improper installation causing hundreds of millions of dollars in damages. Now—decades later—we know that polybutylene is prone to leaks 10-15 years after installation. This is something that your home inspector or plumber will inform you of. Although plumbing manufacturers have not admitted that polybutylene is defective, they did agree to a class action settlement with an initial amount of nearly 1 billion dollars (minimum, likely more).

Risks of polybutylene piping in your home

If your home has Poly B pipes, you could be looking at the following concerns:

Increased potential for leaks
Undetected pinhole leaks leading to water damage and mold
Hidden damage inside walls and ceilings
Insurance issues such as increased premiums or difficulty obtaining insurance
Difficulty selling your home due to perceived problem

What should you do if you have poly b piping in your home?

Most plumbers will recommend replacing the entire system with new PEX piping. This is the only certain way to prolong the life of the home’s piping, however, the cost to replace an entire system can be somewhere between $4,000 and $15,000, or more. Get a quote from some reputable local plumbing contractors, as there are many variables in construction techniques; it’s very difficult to accurately predict how much a large project may cost. Re-piping may not be very complicated; much of the associated cost is actually for the drywall work and labour to repair, patch, and paint the walls (and ceilings or floors).

Poly B piping in unfinished basement ceiling

HVAC, electrical, and structural systems also pictured.

Alternative materials to polybutylene

Kitec is another plastic piping material that was used in the past (1995-2007), though it was not very widely. Kitec is usually orange (or blue) in colour and has fallen out of favour with plumbers and home builders, similarly to Poly B. These days, plumbers use a flexible plastic piping material called PEX, which seems to be much more resilient. PEX is usually whitish and translucent, or, blue or red to indicate cold and hot water supply. Copper is considered to be very reliable and is still commonly used, especially in proximity to high temperatures, for example near a hot water tank metal vent. Copper is more heat resistant than plastic.

Feel free to reference the photos in this article to help you identify your piping material, and remember: if you’re not certain about what piping material is in your home, call a local home inspector or qualified plumber to help you identify it.