Poly-B under the kitchen sink only in my Calgary house?

A short section of Poly-B under the kitchen sink is a very different situation from whole-house piping, and it does not automatically mean a full repipe. Replacing just those few feet of supply line is a small job, usually billed at the plumber's rate of about $85 to $150 an hour plus a call-out fee, depending on how the cabinet is configured and what fittings are involved.

What actually matters with a small Poly-B run

Poly-B is not illegal, and the Province of Alberta is clear that existing installations are not required to be replaced. The concern with Poly-B tends to centre on the fittings and on age: Alberta's fact sheet notes that most installations here used copper or brass insert fittings, which have a better track record than the plastic fittings reported to cause more problems elsewhere. If the short run under your sink uses brass or copper compression fittings and shows no discolouration, cracking or weeping at the joints, a plumber may tell you it is fine to leave alone for now.

That said, under a kitchen sink is one of the easier places to swap pipe, because everything is accessible without opening walls. If a plumber is already there for another reason, or if the fittings look worn, replacing that short section with PEX or copper while the cabinet is open is a reasonable call.

Check with your home insurer. Some insurers ask about Poly-B; what they do with that information varies by policy and company, so a call to your insurer is worth making before you decide whether to replace it.

On permits: Alberta's Permit Regulation does not require a permit to change a faucet, trap or valve when the piping itself does not change; replacing a section of supply pipe is closer to altering the piping, so ask the plumber or the City of Calgary whether your scope needs one. If the plumber needs to go further into the wall or change the shut-off valve location, the scope changes and so might the permit requirement. Ask the plumber to confirm before work starts.

A homeowner in Calgary who owns and lives in the home may take out a plumbing permit for work that does need one. Gas is a separate matter and is not involved here.

What a fair quote should include: a fixed price or an hourly rate plus call-out fee, the pipe material and fitting type being used, confirmation of whether a permit is needed, and a warranty on both parts and labour in writing.

It helps to settle one thing up front: if the plumber opens the cabinet and find the Poly-B runs further than expected, what does the price become, and is that in the quote?