If water drips or pools around the base of your toilet, may be leaking or--if you live in a warm, humid climate--dripping condensation (called sweating). In humid climates, warm room air may condense on a toilet's cold porcelain surfaces and drip onto the floor. This should be dealt with because the moisture encourages mold and, over time, can rot the subflooring. If sweating is not the problem, please see How To Repair Toilet Leaks.
Unlike other fixtures and furnishings in a house, a toilet doesn't have a chance to warm up to room temperature because it is continually refilled with cold water. The warm, moisture-laden air in a bathroom reaches the toilet's cold surfaces and condenses there.
The most common way to deal with a sweating toilet is to insulate the toilet tank with a foam liner. Sold at online and at home improvement centers, tank liners are glued to the toilet tank's inner surfaces.
To install a tank liner, first turn off the water supply valve at the wall and flush the toilet to empty the tank. Use a towel or rag to dry the tank's inner walls. Cut and attach the insulation panels according to the manufacturer's directions.
For a surer and more permanent solution, you can have a tempering or "anti-sweat" valve installed on the cold water line that supplies the toilet. This special device mixes a little hot water from a hot water pipe with the cold water supply that goes to the toilet.
