Condensation on the toilet tank

November 10th 2010
Condensation on the toilet tank

Q) I have constant condensation on the toilet tank in our main bathroom, but not in the other bathrooms in our house. Why is this happening? How can I correct this problem?

A) Condensation on a toilet tank is created because the tank is colder than the surrounding air. The tank is colder because of the cold water that is entering the tank each time the toilet is flushed. In most cases homeowners find that the condensation is more prevalent in summer months when the air has high humidity. There are a couple of methods that you can use to eliminate or reduce the condensation on your toilet tank. You should also evaluate your bathroom ventilation system to ensure that it is exhausting excess moisture from the room. (Minimum 80 CFM: cubic feet per minute)

You can insulate the toilet tank with a liner. Insulating liners are available as kits at most hardware stores. They are made from polyurethane foam and then glued to the inside of the toilet tank. This provides an insulation barrier from the cold water to the porcelain tank.

If you do not have one, you should add a dehumidistat to control your bathroom exhaust fan, controlling the relative humidity level.