What is the maximum hot water temperature allowed in Ontario?
Hot water supplied to fixtures in a residential occupancy must not exceed 49°C, with exceptions for dishwashers and clothes washers. Showers additionally require pressure-balanced or thermostatic mixing valves.
The 49°C limit exists because water at 60°C causes third-degree burns in seconds, and children and the elderly are most at risk. But storage water heaters should still be set around 60°C to control Legionella growth in the tank — the code resolves this tension with tempering: a mixing valve at the water heater or at fixtures blends the stored hot water down to a safe delivery temperature. Showers and tub-showers have a separate requirement for pressure-balanced or thermostatic valves so a toilet flush elsewhere in the house cannot cause a scalding pressure swing. Inspectors check delivery temperature at fixtures, not just the tank setpoint.
Tap water hotter than 49°C scalds fast — especially kids. The fix is a small mixing valve that blends hot tank water with cold before it reaches your taps, so the tank can stay hot enough to kill bacteria while your shower cannot burn anyone.
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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.