How to stop toilet tank from sweating

How to stop toilet tank from sweating

Sweating is not only associated with human beings but toilet tanks as well, especially when the humidity rises. If your toilet tank sweats and you have no clue what is happening or the damage it will cause, you need to read this till the end.

To some people, they wonder why toilet tanks sweat when it is not a living thing, or where the sweat comes from and how it can be prevented. The truth is toilet tanks do sweat, and the sweating comes from the condensation build-up caused by the discrepancy in the temperature.

You don’t have to be confused, toilet tank sweating has no resemblance with a plumbing malfunction or a leak. It comes majorly from the temperature of the water inside your tank and your room. Once there is a huge difference between the temperature level of your room and the toilet tank, condensation is going to form. This is why most toilet tanks sweat in the spring and not in summer (Just like human beings). Isn’t it funny?

Keep reading to find out how to stop your toilet tank from sweating.


How does sweat form on toilet tanks

During the spring, the cold water in the toilet tank results in the cooling down of the tank’s surface. When the cold surface comes in contact with the warm air from the bathroom, condensation will set in and sweat will form. In such a case, we said the tank is sweating.

When there is too much condensation buildup, little drips and drops may start to move down your toilet and splash to the bathroom floor. Therefore, even though a “drip here and there” may not be enough to worry you, if left untreated, a “drip here and there” over time can cause rotting and mold, necessitating the replacement of the bathroom floor as well as the flooring base around the toilet.

Most of the time it often causes unpleasant smells which can lead to diseases and infections. It can also lead to damage to the floor or drywall. This is why it is essential to stop the toilet tank from sweating.

Ways to prevent toilet tanks from sweating

Thankfully, there are several ways to preventing your toilet tank from sweating and everything relies on reducing the air’s humidity and providing a more suitable medium for water usage. This method entails:

Use of Anti-sweat valve

Use of Anti-sweat valve

Anti-sweat valve remains the most suitable means of stopping your toilet tanks from sweating. It involves the installation of an anti-sweat valve in your toilet to prevent condensation from forming. It works by running cold water to the toilet water line with a little addition of hot water to increase the water temperature high enough to warm up the tank.

By balancing the water temperature with the room temperature, condensation will not occur. The process is not that complex and takes less time to install an anti-sweat valve. You can get an anti-sweat valve online or in any nearby store.

How to install an anti-sweat valve

install an anti-sweat valve

The process of installing an anti-sweat valve involves the preparation phase and the installation phase. Let’s check what each means:

Preparation phase

  • Start by shutting off the main water supply to the toilet, if possible the entire house.
  • Drain the hot and cold water supply to the toilet by Opening up the sink and flushing the toilet.
  • Make all connections to the valve with brass compression.
  • Thread a compression adapter to the three-valve port.
  • Note where and mark the location on the pipe where the valve’s center output port meets the vertical pipe segment. Mark the bottom inlet port’s position on the horizontal pipe as well.
  • The pipe part can then be removed using a hacksaw.
  • After that, extend the vertical pipe going down from the toilet with a 6-inch-long stub of 1/2 inch. pipe by soldering a 90-degree L-fitting to it.
  • Utilize a MAPP gas torch and lead-free solder. Lead-free solder is more difficult, and MAPP gas works more rapidly and burns hotter than propane.
  • Locate a nearby hot water pipe and cut off a part to accommodate a new copper T-fitting after the cold water line is prepared for the valve.
  • Install a short vertical riser pipe with a 90-degree L-fitting and a short horizontal pipe stub after splicing the T-fitting into the line.
  • The location of the valve installation will be indicated by pointing the stub in that direction.
  • Connections T and L should be soldered.
  • Add a section of pipe to reach the valve location.
  1. Installing the anti-sweat valve
  • Coat the threads of the compression adapter gently with a pipe dope also known as a pipe joint compound (
  • Using a wrench, tighten the adapters after threading them into the valve ports.
  • The pipes should be inserted into the adapters after each end has been secured with a nut and compression ring.
  • After applying pipe dope to each compression ring, thread the nuts onto the adapters.
  • Tighten each nut with a wrench.
  • Reopen the main water valve and check for any leaks.
  1. Insulating the tank interior.

Another perfect way of stopping tank sweating is by insulating the toilet tank interior. It is a method some homeowners don’t know exists. When you insulate the tank with a toilet tank insulator it will bring the water temperature to the minimum and regulate the humidity level.

An insulated toilet is essential in a hot and humid area where toilet tank sweating is a constant problem. This insulator can be sold in-store and contains foam to make it adhere to the tank internally and prevent water from getting too cold. The insulated tank will not absorb moisture and prevent sweating.

You can also use bubble wrap and place it inside the toilet to create a layer between the water and the toilet tank. A bubble wrap at hand is the best fit for this purpose. Some people don’t recommend this method and prefer using an air dehumidifier. Getting an insulation kit is also important when using this method.

  1. Reducing bathroom humidity and heat.

There are several ways to get this done. They include:

  • Using a vent fan when you take a shower.

If you have a vent fan in your toilet, always switch it on before showering and ensure you leave for like 10 -20 minutes after finishing the shower. Venting out the humid and warm air in the toilet will help stop and prevent toilet sweating. However, if you don’t have a vent fan, another method is to crack open the door to reduce moisture, but this can only work if the humidity outside is also low.

  • Clean the shower wall to remove moisture.

You can also employ this method, you wipe or clean the water on the shower wall after taking a bath. You can extend your cleaning to the tub surface too or the shower floor. This is done so that the water on the wall will not evaporate into the surrounding air and form sweat on the toilet tank.

  • Keep toilet windows closed on warm humid days.

Toilet windows should be closed when you notice an increase in the air humidity. Truly, what would come to your mind is opening the door on a hot day, however, when you see that it is warmer both outside and inside, applying this method can help lower the rate of condensation.

  • Run Air conditioning or dehumidifier.

An air conditioner will bring closer the temperature of the air around the toilet to that of the water in the tank. Similarly, a dehumidifier or an air conditioner will lower the amount of moisture in the air, which will decrease condensation. Once condensation is reduced tank sweating will be stopped or prevented.


Toilet tank sweating is caused as a result of condensation buildup on the toilet tank majorly due to the rise in the warm and humid air. Tank sweating doesn’t seem like a big problem but can be irritating and harmful. Most of the time it can also lead to the growth of mold, and since our health is very important, stopping tank sweating is also very essential. The steps above highlight the necessary procedure to follow.

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