Plumbing is one of the most consequential — and most frequently misunderstood — renovation elements. Here’s what Ontario homeowners need to know in 2026.
When permits are required:
- Adding a new bathroom (new rough-in)
- Relocating any plumbing fixture
- Adding drain or supply connections
- New exterior water service or drainage
When permits are NOT required:
- Replacing a fixture in the same location (like-for-like)
- Replacing a faucet, toilet, or showerhead
The drain stack reality:
Toronto homes built before 1960 typically have cast-iron drain stacks that are 60–80 years old. Cast iron corrodes internally over time. Signs: slow drainage, gurgling sounds, rust stains. Replacement during basement renovation: $3,000–$8,000.
Supply line assessment:
Homes built before 1970 may have galvanized steel supply lines. These corrode from the inside — reducing flow, potentially contaminating water, and eventually failing. Copper or PEX replacement: $4,000–$12,000 for full home replumbing.
PEX vs. copper:
Both acceptable under Ontario Building Code. PEX is increasingly dominant: flexible, freeze-resistant, faster to install. Copper preferred for some commercial applications and by some contractors.
Water pressure:
Toronto’s municipal water pressure can reach 90+ psi. A pressure reducing valve (PRV) protects appliances and reduces leak risk. Cost: $300–$800 installed.
Share your plumbing renovation experience — what you found, what you replaced, and what your contractor recommended.
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