Why is my toilet sweating and what can I do about it?

01 Jul

Why is my toilet sweatingWe hear this question often and there are several solutions.

A dripping toilet is a common problem in summer in New England often due to very cold well water and high humidity inside the home since many of us do not have central air conditioning. Finding a good solution will stop the sweating tank from leaking onto and ruining floors, creating a slipping hazard or worse – developing a mold and mildew problem nearby.

First let’s understand what causes dripping.

Combinations of cold water, high humidity (as caused by a hot steamy shower or basements), low air circulation, an improperly adjusted fill valve, or a leaky flapper can be the culprits.

The simplest and least expensive cure is a drip tray that can easily be installed by the homeowner that will catch the condensation and allow it to evaporate, thus saving your floors.  They cost just a few bucks, and they actually work.  The downside is they do not look attractive.

Another cure is to check the flapper to see if it is not sealing completely.  A leaky flapper will allow ice cold water to continuously be introduced into the tank which is sure to cause sweating in addition to wasting our valuable water. If water is seeping past it, replace the flapper for under $10 at your local hardware store or home center.

Next, try reducing humidity in the room by using a dehumidifier or leaving a bathroom door open to allow circulation after a steamy shower. This will allow the bathroom to more quickly dissipate the moisture.

Insulating your toilet tank may work, but it is not one of four preferred solutions.  Replacing the toilet would be wiser as you would likely find a more efficient toilet that uses less water, fills faster and probably even looks better.

If all else fails, have a plumber install a mixing valve, also known as an anti-sweat valve.

If everything else is in order and you still have condensation on your toilet tank, you may have high usage that keeps a good flow of cold water entering the tank due to flushing often.  In this case, you may want to have a plumber install a mixing valve to add a small amount of hot water to the cold incoming water.  This is a pretty sure-fire solution, but one which should not be employed unless all else fails.  Obviously you will be increasing your hot water usage, but the minimal cost will be very well offset by eliminating the damage caused by a drippy, sweaty toilet tank.



Nicholas Paquette
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