
Causes and solutions for condensation on toilet tanks:
- Condensation may mask a leaking toilet. ...
- Is there enough ventilation in the bathroom? ...
- In the winter, the condensation may be caused by using a humidifier on your heating system. ...
- Position a drip tray under the tank. ...
- Install a toilet tank liner kit to the inside of the tank liner. ...
Do you have condensation on your toilet tank?
Don't Ignore Tank Condensation! While a few drops of water on a tank may seem harmless, condensation on toilet tanks can be severe if not dealt with quickly. Some of the long-term risks or issues include:
Why is there condensation on the inside of my tank?
This is because the water entering your tank is cold and cools the tank's surface down, making it easy to pull moisture from the air. Think of it as similar to the condensation on an iced tea in summer.
Why is my bathroom toilet tank cold?
This is especially true in bathrooms where there’s more moisture and often less ventilation. When humidity lingers inside a bathroom and it hits the cold porcelain toilet tank, it creates condensation. Although this is a seemingly small problem, it can cause damage to flooring or drywall and potentially lead to mold if it’s not addressed.
Why is water coming out of my toilet tank?
When the weather turns hot and humid, there's a lot of moisture in the air. At the same time the water entering the toilet tank is comparatively cold—about 50° to 60°F. When the warm, moist air hits the cool porcelain toilet surfaces, the air condenses, turns to water and soon drips onto the floor.

How do I stop condensation in my toilet?
Warm up your toilet. Insulating your toilet tank can prevent water from condensing on the surface. You can line the tank with an insulating kit, or you can cover the entire outside of the tank with a tank cover. If you can prevent the cooler tank from meeting up with the warmer air, condensation won't occur.
Is it normal for a toilet to have condensation?
A: When temperatures outside begin to rise, the temperature inside the home does, too. This is especially true in bathrooms where there's more moisture and often less ventilation. When humidity lingers inside a bathroom and it hits the cold porcelain toilet tank, it creates condensation.
What does it mean when your toilet bowl sweats?
When the weather turns hot and humid, there's a lot of moisture in the air. At the same time the water entering the toilet tank is comparatively cold—about 50° to 60°F. When the warm, moist air hits the cool porcelain toilet surfaces, the air condenses, turns to water and soon drips onto the floor.
Why is my toilet sweating in the winter?
Toilet tank sweating is caused by a combination of factors: the temperature of the water coming into the tank and the temperature and humidity of the air in the room. When the water is colder than the room -- and thus chills the tank -- sweating occurs.
How do you stop water pipes from sweating?
Seal joints between lengths of tubing with special “peel-and-stick” seam-sealing tape or foil duct tape. If your cold water pipes are sweating more than you are on these hot summer days, here's the simple cure. Run down to the local home center, lumberyard or hardware store and pick up some foam pipe insulation.
How to stop condensation from ringing in toilet?
Just as you slip a coaster under a sweaty glass to prevent condensation from leaving a wet ring, you can install a drip tray under the toilet tank to catch the excess moisture. It isn’t very attractive, and you’ll need to empty and clean it regularly. But as a cheap fix (under $10), it does buy you time to figure out a better solution.
Why is my toilet sweaty?
When warm, damp air hits a cold surface, condensation forms. Dripping off a toilet tank, this moisture can keep bathroom flooring damp for days, ruining the flooring and even rotting out the sub-floor and floor framing.
What is an anti-sweat valve?
An anti-sweat valve, also known as a mixing valve, is a $30 plumbing part that introduces a little warm water to the cold water feeding into the toilet tank. Plumbers swear by it as one solution that always works. The valve can be a good option for a toilet over a basement where plumbing pipes are easily accessible.
Why does water trickle through toilets?
Water trickling through a toilet not only wastes water and adds to utility bills, it also makes the tank colder -- and more susceptible to sweating -- because your tank is constantly refilling itself with cool water.
How to keep a tank from getting cold?
Insulate the Tank. If the flapper isn’t the culprit, you can keep the tank from getting cold by insulating it on the interior. Some hardware stores and home centers sell do-it-yourself kits for about $20.
When to flush a water tank?
When possible, wait to flush until the room has dried out so you don’t fill the tank with cold water just when the risk of condensation is greatest.
Can you cure a sweaty toilet without money?
If family members cooperate, you might be able to cure a sweaty toilet without spending any money.
How to keep water from condensation in toilet?
Install an antisweat valve in the water-supply line leading to the toilet. An anti-sweat valve adds a little hot water to the toilet water line, which raises the water temperature in the toilet enough to warm up the tank and bowl. That's all it takes to keep condensation from forming, even in the most sultry weather.
How cold is the water in a toilet?
At the same time the water entering the toilet tank is comparatively cold—about 50° to 60°F. When the warm, moist air hits the cool porcelain toilet surfaces, the air condenses, turns to water and soon drips onto the floor. Although a toilet sweats only on warm, humid days, it can drop a surprisingly large amount of water in a very short time.
What is the season for toilet sweating?
Summer is the season for backyard barbecues, days at the beach and family vacations. Unfortunately, your toilet sweating is another sign of the season. In fact, every summer millions of homeowners have to deal with toilets that perspire puddles of water onto the floor.
How to cut out cold water pipe after shutting off?
AFTER SHUTTING OFF the water, use a hacksaw to cut out the section of cold-water pipe to accommodate the new valve.
How to dry out the air in the bathroom?
Use an air conditioner or dehumidifier to dry out the air in the bathroom. However, this approach won't work if you don't have one of these units or don't want to run it all summer.
Can a sweaty toilet tank be used as an insulator?
Several manufacturers make toilet-tank insulators they claim cure sweaty toilets, but most don’t work very well.
Can condensation run down the toilet?
This problem is much more than just a mild annoyance: Condensation running down the toilet can seep under the flooring, rot the plywood subfloor and soak into the floor joists. It can also stain baseboard molding, turn drywall soggy and discolor wall paint with mildew.
Why do I need to fix the condensation on the side of my toilet tank?
Heavy condensation from your toilet tank can drip off and keep your bathroom floor damp for days. Over time, this can ruin your bathroom floor causing wood rot and warping of the sub floor and floor support framing.
So how do I fix it?
A short term solution to prevent damage to your bathroom floor is to fit a drip tray below the toiler cistern. While this is a cheap option, it also creates its own hassles and should not be deemed a permanent fix. You will need to keep changing the water and cleaning the drip tray otherwise it will mould over.
Is there anything else I can do?
You may have a problem with your toiler that is causing this. The ‘flapper’ may not be sealing properly and allowing cold water to constantly refill into the cistern. Your lift chain may also be obstructed and not setting at the correct point. Lift the lid of your toiler and check.
Find out more
If you would like to find out more about toilet repairs then call the professional plumbers. At JSL, we are one of the top rated plumbers in Glasgow. We are completely independent and will always give our customers honest advise and recommendations.
Why does my toilet tank have condensation?
Condensation on the outside of a toilet tank is the result of humid air in the room coming in contact with the cold tank. Similar to what happens on a glass filled with a cold drink. Condensation on a toilet tank is most often a problem in the summer time in humid climates, but can also be a problem in the winter.
Why does my bathroom have condensation?
An exhaust fan in the bathroom may be needed. In the winter, the condensation may be caused by using a humidifier on your heating system. If this is the case, adjust the humidifier. Position a drip tray under the tank. One type has sponges that absorb the condensation and another type has a tube that drains accumulated condensation ...
Why Does My Toilet Sweat (Condensate)?
Any toilet can 'sweat' under the right conditions at any time of year. When the air in your bathroom is humid and touches the cold surface of your toilet tank, condensation forms and drips onto the floor.
Why is my toilet water pooling?
If the water is pooling under the toilet, then it may be a leak problem. Check your supply line, making sure to tighten and fill or replace if necessary. We also recommend tightening your t-bolts or replacing the wax ring if the leaks continue.
How to tell if a toilet is leaking?
Leaking Toilet Tank. One easy way to tell if your toilet is sweating or leaking is to wipe down the water and leave it for a while. If there is water on the outside of the tank that is dripping down, it is a sweating problem. If the water is pooling under the toilet, then it may be a leak problem. Check your supply line, making sure to tighten ...
Why does my toilet drip?
When the air in your bathroom is humid and touches the cold surface of your toilet tank, condensation forms and drips onto the floor. This is because the water entering your tank is cold and cools the tank's surface down, making it easy to pull moisture from the air. Think of it as similar to the condensation on an iced tea in summer.
How to stop toilet tank from sweating?
Some ways to stop your toilet tank from sweating include: 1. Line the tank with an insulation kit according to the product instructions, being wary of the floatation system. 2. Check and adjust or replace the flapper valve.
Why is my toilet tank sweaty?
The room is warmer and often less exposed to the elements via the window, making it the perfect humidity and warmth level to create a sweaty tank. It is the same as if it were a hot summer with a cool toilet tank.
How much water does a toilet need?
That depends on how old the toilet is. Older models from 1982 and earlier require 5-7 gallons of water, much greater than the modern 1.6 gallons.
How to stop condensation in toilet cistern?
There are one or two ways to stop, or very much reduce, condensation on the toilet cistern. The first is to have plenty of air changes in the room. This is easy if your bathroom has a window; you just open it 2 or 3 times a day . If you do not have a window however, you are reliant on the extractor fan to take the hot air (and the smells) ...
How to fix condensation in bathroom?
All of these factors are a recipe for condensation issues. Add heat and water together and you get humidity. The bathroom is absolutely choc a bloc with humidity! Then add to this heat and humidity a very cold surface such as your cold water toilet cistern or the cold water pipes which feed your cistern, the bath and the basin. ...
How does a yoga mat insulate a toilet cistern?
Toilet cistern with Yoga mat glued to the inside to insulate the cistern walls from warm air. When the water is turned on, the yoga mat insulates the cistern but even better than that, some of the water squeezes up between the mat and the sides of the cistern. This behaves then exactly as a wet suit does to a diver.
Why does my toilet have a hole in the floor?
large hole in floor caused by condensation running off of toilet cistern. This cold water makes the surface of the toilet cistern very cold and, or course, the surface of the cold water taps very cold too. The moment the humid hot ar from the bathroom hits the cold surface of the cold pipes or toilet cistern, it immediately turns to liquid, ...
How cold is the water in a bathroom?
Your cold water, coming from the mains, is usually between 5 and 20 degrees celcius. Warmer if it comes from a cold water tank in the loft, but nevertheless, much much colder than the temperature in your bathroom. large hole in floor caused by condensation running off of toilet cistern. This cold water makes the surface ...
Does warm water cool down quickly?
The warm water also cools down very quickly when its mixed with the cold in the cistern, so not much of a solution really. We could box the pipes and the cistern in and make sure that inside the boxing is a lot of insulation keeping everything nice and warm so the moisture in the air does not condense.
Do extractor fans condense?
If you do not have a window however, you are reliant on the extractor fan to take the hot air (and the smells) out of the bathroom and new air to enter through the door. The new air however, is just old air from downstairs. Just as warm and just as likely to condense!
Why does my toilet tank have condensation?
This is especially true in bathrooms where there’s more moisture and often less ventilation. When humidity lingers inside a bathroom and it hits the cold porcelain toilet tank, it creates condensation.
How to get rid of condensation on toilet tank?
It’s advised to dry out the room with either an air conditioner or dehumidifier to make the surrounding air cooler and wick away excess moisture. Regularly running air conditioning units or dehumidifiers, especially on extra humid days, will help reduce condensation on the toilet tank.
How to tell if toilet flapper is leaking?
To see if the flapper is the culprit, you can add food coloring to the water in your toilet tank. After adding the food coloring, wait about an hour and then check the flapper to see if the color shows up in your toilet bowl. If it does, it’s likely your flapper is leaking and needs to be replaced. Replacing a flapper is a straightforward fix ...
What is the moistest room in the house?
Thanks to baths and showers, bathrooms are usually the moistest room in the house. They also don’t readily receive a lot of ventilation (especially if you don’t have a ventilation fan). When eliminating toilet tank sweat, aim to reduce the humidity in the bathroom.
What is an anti-sweat valve?
Even in the hottest conditions, an anti-sweat valve can help prevent your toilet tank from sweating. These valves work specifically to add hot water to your toilet’s water line, which will raise the temperature in the toilet to heat both the tank and the bowl. Because it works to equalize the temperature between the toilet and the room, ...
Can you put bubble wrap in a toilet?
You can place bubble wrap around the inside of the toilet, creating a layer between the toilet tank and the water. If you don’t have bubble wrap on hand, rigid or flexible foam insulation works, too. Stores also offer insulation kits for your toilet tank.
Do toilets need insulation?
Your tank needs insulation. Insulating a toilet is an option that many homeowners might not know exists. Still, an insulated toilet can be beneficial in hot, humid locales where toilet tank sweating can be a constant problem. Most major toilet manufacturers have an option with insulation, but you can also try a DIY solution.

Why Do I Need to Fix The Condensation on The Side of My Toilet tank?
So How Do I Fix It?
- A short term solution to prevent damage to your bathroom floor is to fit a drip tray below the toiler cistern. While this is a cheap option, it also creates its own hassles and should not be deemed a permanent fix. You will need to keep changing the water and cleaning the drip tray otherwise it will mould over. You should only use this as a short term solution. An easy fix can be simply changin…
Is There Anything Else I Can do?
- You may have a problem with your toiler that is causing this. The ‘flapper’ may not be sealing properly and allowing cold water to constantly refill into the cistern. Your lift chain may also be obstructed and not setting at the correct point. Lift the lid of your toiler and check. If you can’t see anything, add a few drops of food colouring into the tank. If after a while, you see some of the fo…
Find Out More
- If you would like to find out more about toilet repairs then call the professional plumbers. At JSL, we are one of the top rated plumbers in Glasgow. We are completely independent and will always give our customers honest advise and recommendations. We stick by our values and we use the booking system ‘ServiceM8’ which allows you to book our plumbers for a time slot that suits you…