In a nutshell
Copper is proven, rigid and long-lasting, and it has served Toronto homes for generations. PEX, a flexible cross-linked plastic, is faster to install, needs fewer joints and handles freezing better. Both are approved under the Ontario Building Code for water supply. For a full repipe in an older house with finished walls, PEX often wins on practicality. For exposed runs and mechanical rooms, copper still has a lot going for it.
Working through it
Compare the materials
| Copper | PEX | |
|---|---|---|
| Installation | Soldered or press fittings, rigid lengths | Flexible runs, crimp or expansion fittings |
| Joints | Many, at every turn | Fewer; bends without fittings |
| Freezing | Can split when frozen | More tolerant of expansion, though not immune |
| Sunlight | Fine | Degrades in UV; keep covered |
| Noise | Can transmit water hammer | Quieter |
| Recycling | Valuable scrap | Limited |
Think about your house
In an older home with plaster walls, snaking flexible PEX through existing cavities can mean fewer openings and less patching. In a basement with exposed joists, copper runs neatly and looks tidy. Many plumbers use both: copper near the water heater and meter, PEX for the branch runs.
Think about your water
Toronto's treated lake water is generally gentle on copper. Pinhole leaks do occur in older copper, often linked to age, velocity or installation details. PEX does not corrode, but its fittings, especially some brass types, can be affected by water chemistry over long periods. Good fittings and installation practice matter more than the pipe itself.
Clues worth noticing
Signs your current piping is due for attention include:
- Green or white crust on copper joints.
- Repeated pinhole leaks in different spots.
- Rusty water or low pressure from galvanized steel.
- Older grey polybutylene pipe, which has a poor failure history.
A note on cost
Material prices move, and labour usually outweighs them. PEX tends to be quicker to install because it bends around corners and needs fewer fittings. Copper takes more time but leaves a tidy, durable run. Ask for written quotes on both if you are unsure, and compare the scope, not just the total. A cheaper quote that skips new shut-off valves or proper supports may cost more later.
Signals that it needs a licensed plumber
If you are planning a renovation or seeing repeat leaks, talk to a plumber about repiping. We will look at what you have, how the house is built and where pipes can run, then suggest a material that fits. For hot water connections, see water heater repair. Our article on water hammer also explains why pipe material affects noise.
One last point: whatever pipe runs through your walls, it needs a working main shut-off and accessible fixture valves. Those small parts do more to limit damage than any pipe choice.
Calls we field, answered plainly
Is PEX safe for drinking water?
PEX certified to the relevant drinking water standards is approved for potable water in Ontario.
Can PEX and copper be mixed?
Yes. Transition fittings join them, and mixed systems are common.