Leaky toilet tank

Leaky toilet tank with water under tank

A common sign that you have a leaky toilet tank is water on the floor beneath the toilet. Follow these easy steps to diagnose and then fix your leaky toilet tank.

First, inspect the tank to determine where the water is coming from. Water is typically coming from loose nuts attaching the tank to the bowl, a crack in the tank, from around the toilet handle, from around the tank lid or from condensation on the tank. If, after inspecting the toilet, you believe the problem is with the bowl, read our instructions on fixing a leaky toilet bowl.

Loose nuts causing leaky toilet tank

Leaky toilet tank bolts
Tightening loose bolts under a leaky toilet tank may fix the problem.

One source of a leaky toilet tank is loose nuts where the tank is attached to the bowl. To tighten the nuts in the tank use a flathead screwdriver to steady the bolt inside the tank while using an adjustable wrench to tighten the nut on the underside of the tank.

If water still leaks from around the nuts you will need to replace the washers. Simply hold the bolt steady with a flathead screwdriver while removing the nuts with an adjustable wrench. Be certain to get the proper size washer for the bolt.

Crack is causing leaky toilet tank

If there is a crack in the tank it will need to be replaced. Carefully check the exterior of the tank for any cracks. Look closely around the holes where the bolts attach the tank to the toilet bowl.

Water is leaking through the handle

Reposition the float ball
Leaky toilet tank from float ball
Reposition the float ball if it is too high and water is leaking out from around the toilet handle

If the float ball is too high it will allow water to run into the overflow pipe and out of the handle. You can bend the float arm down slightly to keep the water about 1 inch below the top of the overflow pipe. Flush the toilet to a make sure enough water is getting into the bowl. If the toilet does not flush completely you may need to adjust the float ball back up slightly to get more water in the tank.

Adjust a water-intake assembly

Your toilet may have a water-intake assembly instead of a float ball. To adjust the water level in the bowl so it does not flow into the overflow pipe, pinch the clip attached to the thin metal rod and slide it and the cup down to lower the water level. Sliding the clip and cup up will raise the water level. Try moving the clip about an inch at a time.

Adjusting a metered fill valve

Your toilet may have a metered fill valve instead of a float ball or water-intake assembly. To adjust the water level, simply take a screwdriver and turn the knob counterclockwise and half a turn at a time to lower the water level. Turning the know clockwise will raise the water level.

Shorten overflow pipe

If the overflow pipe is too long you can use a hacksaw to shorten it. The pipe should be 1/2 inch below the handle.

Water is leaking around the flush valve

If the flush-valve assembly is damaged you will need to replace it. You might first try replacing the gasket over the locknut on the assembly and then the assembly itself.

You will need to remove the tank to do this. Be certain to turn off the water supply and flush the tank to drain it. You might also want to place newspaper and towels on the floor to soak up any water that may leak out. Using and adjustable wrench loosen the nuts at the supply tube and push the tube aside. Next, use a flat-head screwdriver to hold the bolts inside the tank still while using an adjustable wrench to loosen the nut on the bottom of the tank. You will then be able to lift the tank off of the bowl. Lay the tank on the newspapers or towels.

To replace the flush-valve assembly first remove the old one by unscrewing the locknut on the bottom of the tank. Use a hacksaw to cut the new overflow pipe to 1/2 ince below the tank top. Put plumber’s putty on the washer at the base of the flush-valve assembly and push the assembly against the tank opening, removing any excess putty. Use a monkey wrench to tighten the locknut. Replace the gasket over the locknut and replace the tank on the bowl and reassemble them.

Water is spraying from the ball cock

The ball cock opens and closes as the float ball falls and rises with the water level in the tank. This action controls the flow of water into the tank. With a plunger-style ball cock the float arm pushes the valve plunger and washer to stop the water flow. With a diaphragm-style ball cock the plunger pushes against a rubber diaphragm.

Before working on the ball cock turn of the water and flush the toilet to empty the bowl. Remove the screws surrounding the ball cock assembly to gain access to the washers or diaphragm. You may need to slide the float arm out of the way to gain access to the assembly.

Remove the washers or diaphragm from the valve plunger with a small screwdriver. Use vinegar and a small brush to clean sediment from inside the ball cock and washer or diaphragm. Once cleaned reassemble the parts and the ball cock. If any of the pieces appears damaged or if the water continues to spray, replace the ball cock.

Condensation is forming on the tank

In hot conditions condensation may form on the tank. You can purchase an insulation kit at your hardware or plumbing supply store. Before installing the insulation on the bottom of the tank you will need to turn off the water supply, flush the toilet to drain the tank and use a sponge to soak up any water remaining in the tank. Install the foam insulation according to the instructions.

Water is spraying from the refill tube

If water is spraying from the flexible refill tube simply purchase a replacement of the same diameter, cut to proper length and replace the old tube.

Water is leaking from the shutoff valve

If water is leaking from around the shutoff valve you can use an adjustable wrench to tighten the coupling nut.

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