How to Fix Leak Between Toilet Tank and Bowl
Is your toilet leaking between the tank and the bowl? If you see water pooling on the floor, leaking from the tank bolts, or around the base, it's time to replace the gasket and hardware.
A worn tank-to-bowl gasket or loose bolts usually cause this leak. Cleaning chemicals, bacteria, hard water, city or well water, can all break down these parts over time.
This is unlike a running toilet, where the water leaks within the tank because the toilet flapper is loose.
What causes leaks between the tank and bowl?
The tank-to-bowl gasket creates a water tight seal between the tank and bowl. If your toilet is leaking from the tank bolts, the best fix is to replace the gasket and hardware kit.
Since removing the tank from the base isn't as common, you might want to consider replacing everything. We recommend our 2X Complete Toilet Repair Kit, which is made of a material that is 2 times stronger.
Old Gasket
Over time, gaskets can wear out from exposure to chemicals, bacteria, and hard water. If you find your gasket damaged or old, replacing it will stop leaks.
If you’ve recently replaced the gasket or flush valve but still notice leaks, check for the following issues.
Unevenly Tightened Tank Bolts
When tightening, it is important to alternate sides. This helps you keep the tank level and stable. If not done properly, it could open a path for water to leak.
We recommend having a partner apply even pressure to both sides of the tank. This evenly compresses the gasket as you tighten the bolts, helping maintain an even seal and prevents gaps that could cause leaks.
Be careful not to overtighten, which could crack the porcelain.
Incorrect Gasket Size
Ensure you have the right gasket size for your toilet. Tank-to-bowl gaskets come in two sizes, standard 2-inch and large 3-inch. Make sure you've chosen the correct one. You can find a replacement gasket if you bought the wrong size by viewing our tank-to-bowl gaskets.
How to Install a Tank-to-Bowl Gasket
- Shut off the water supply to your toilet. Then flush the toilet to drain the water from the tank.
- Place a bucket under the toilet tank to catch excess water.
- Disconnect the water supply line, and remove all old bolts, metal washers, and nuts from the tank.
- Carefully disconnect the tank from the bowl and remove the old sponge gasket.
- Place the new red gasket over the mounting nut threads.
- Carefully set the tank onto the bowl. Use the bolts, rubber washers, washers, and hex nuts to attach the tank to the bowl. Have a friend apply downward pressure to keep the tank level as you tighten the nuts alternatingly until the tank is stable.
- Do not overtighten the bolts; doing so may cause the porcelain to crack.
- Reassemble the toilet and turn the water supply line back on.
