How do I stop my toilet from sweating?

Toilet sweating occurs when warm, humid air contacts the cold surface of your toilet tank, causing condensation to form and drip onto your bathroom floor. This is especially common in Ottawa during humid summer months when there's a big temperature difference between the cold water in your tank and the warm bathroom air.

The most effective solution is to install a toilet tank liner or insulation kit. These foam liners attach to the inside walls of your toilet tank, creating a barrier that prevents the cold tank surface from directly contacting the warm air. You can find these kits at most hardware stores for $15-30, and they're relatively easy to install yourself by draining the tank, cleaning the surfaces, and adhering the foam pieces.

Reducing bathroom humidity is equally important for preventing toilet sweating. Run your exhaust fan during and after showers, ensure proper ventilation, and consider using a dehumidifier if your bathroom consistently feels muggy. In Ottawa's climate, this is particularly helpful during summer months when humidity levels spike.

For a more permanent solution, especially if you're renovating, consider installing a mixing valve that slightly warms the water entering your toilet tank. This reduces the temperature differential that causes condensation. However, this requires plumbing modifications and should be done by a licensed plumber to ensure proper installation and compliance with Ontario Building Code requirements.

If toilet sweating is causing water damage to your flooring or the problem persists despite these measures, it's worth having a plumber assess whether there are underlying ventilation or plumbing issues contributing to the problem.