Why it matters to the pipes
Galvanized supply is ordinary steel dipped in zinc, which holds rust at bay for a while. It was widely used for water supply lines in houses built before the 1960s. Over many years, the zinc wears away and the steel beneath begins to rust. Rust and mineral scale build up on the inside wall, steadily narrowing the pipe and eventually leading to leaks at threaded joints. Pipes that have been in service for sixty years or more are often near the end of their useful life.
Have to hand
- A flashlight and a bucket
- Old towels and a pair of gloves
- The way to the main valve
Put the tools down if
- Water will not stop at the valve
- Sewage rises in a floor drain
- You smell gas near the heater
The steps, in order
- Identify the pipe. Galvanized pipe is dull grey or silver, with threaded fittings. A magnet will stick to it, unlike copper or lead.
- Check the water pressure. Weak flow at upper-floor fixtures, especially when two taps run at once, is a classic sign.
- Look at the water colour. Brownish or rusty water when a tap is first opened suggests corrosion inside the pipe.
- Inspect the joints. Rust streaks, crusty deposits or dampness at threaded fittings point to slow leaks.
- Clean the aerators. Flakes of rust collecting in faucet aerators are a telling sign.
- Note mixed materials. Where galvanized pipe joins copper directly, without a dielectric fitting, corrosion speeds up at the joint.
Common missteps
- Patching one leak after another. Once several joints are failing, the remaining pipe is likely in similar condition.
- Replacing only visible sections and leaving galvanized pipe hidden inside walls.
- Assuming low pressure is the city's fault. Restricted galvanized pipe is far more often the cause.
- Forgetting that older galvanized lines are sometimes connected to a lead water service, which should be checked at the same time.
When to ring for help
Call if you see leaks, rusty water or a steady drop in pressure. A plumber can test the pressure at the main, assess how much galvanized pipe remains and recommend whether targeted repairs or full repiping makes sense. If you suspect a hidden leak behind a wall, leak detection can find it with minimal opening.
Replacing supply piping inside the house may require a permit depending on the scope. Our guide to plumbing permits in Toronto explains the general rules.
What replacement involves
Replacing galvanized supply lines usually means running new copper or PEX through the house, connecting to each fixture and the water heater. A good plumber will plan the route to minimise openings in finished walls, often using basement ceilings, closets and existing chases. The work can usually be done in stages, but completing it in one project tends to be more efficient and avoids leaving weak sections behind.
Ask for the routing plan before work begins.