Fixing Toilets That Do Not Shut Off Properly

By Gil Johnson

Over time, toilets may leak small amounts of water from the tank into the toilet bowl causing more water to be added. This not only uses water needlessly, but can be startling if it occurs during the night when you may be awakened by the sound of the tank being refilled. Usually this is caused by one of three problems which can easily be fixed. The water level in the tank may be at or above the top of the overflow pipe; the flapper or stopper ball that closes off the outlet at the bottom of the tank may be defective; or the fill valve may need replacing. This guide does not address repairs that occur when water leaks onto the floor from the tank or at the floor level. If there is interest, a future guide could address these problems.

Any of the problems of water leaking from the tank into the toilet bowl can be repaired by someone with little or no vision by having the right tools, correct replacement parts, and following these steps.

Tools you may need:

  • Straight or philips screw drivers
  • Channel lock pliers
  • 8-inch or 10-inch adjustable wrench

Parts you may need depending on the cause of the leakage

  • Replacement flapper
  • Replacement fill valve

Steps to adjust the water level in the tank

You can tell by touch if the water level is above or near to the top end of the overflow pipe. If this is the case, water is probably trickling down the overflow pipe and down into the toilet bowl. The amount of water in a toilet tank is usually adjusted in one of two ways. Older style fill valves have a threaded rod about 6 or 8 inches long which is attached near the top of the fill valve. A plastic or metal cylindrical float is attached to the end of the rod. The float is about 2.5 inches in diameter and 3.5 inches long and is rounded on each end. As the water level in the tanks raises, the float and attached rod gradually closes the fill valve until it is totally turned off. If the water level is above the overflow pipe, the valve can not totally shut off. If there is a water level adjustment screw on the top of the fill valve, you can lower the level of the water by turning it. If there is no adjustment mechanism or you can't find it, you can adjust the water level by slightly bending the float rod down with your hands thus forcing the valve to close with the water at a lower level.

Tip: Before bending the rod, make sure the rod and float are hand tightened so that they will not rotate thereby eliminating the effectiveness of the bend in the rod. If it is difficult to bend the rod while it is inside the tank, you can unscrew the rod from the valve, bend the rod and then replace it. Be sure when you reinstall the rod and float that the bend you have just made has slightly lowered the float.

Tip: You may want to bend the float rod down a bit and then make another bend so that the float is not pointed downward but is relatively parallel to the surface of the water.

Newer style fill valves have a plastic float that slides up and down the outside of the fill valve. This float is attached to a connector rod which gradually turns the fill valve off. If the water level is too high, water can run into the overflow tube. The float can be adjusted by setting the top stop by adjusting a pinch clamp on the rod. This is quite easily done and doesn't require any tools.

Either of these adjustments take very little time and can solve the problem.

Steps to replace the flapper or stopper ball

The opening at the bottom of the tank is closed off allowing the tank to fill with water with one of two different designs. A "flapper" or "stopper ball" is attached to the flush lever. When the flush lever is raised the flapper or stopper ball is pulled up allowing water to flow from the tank into the toilet bowl. The stopper ball looks like a round rubber ball with a hole in the bottom and a threaded insert at the top. The top of the ball is attached to a threaded rod which is linked to the flush lever arm which, when raised pulls the stopper ball away from the opening in the bottom of the tank allowing water to flow into the toilet bowl. As the water flows out of the tank, the ball is drawn down and closes off the opening at the bottom of the tank. If the ball has developed cracks as can happen over time, it will not properly seal off the opening and water may trickle down into the toilet bowl.

Tip: If the flapper or stopper ball has developed cracks, you can often detect these by examining the bottom of the stopper ball or flapper. Very often you can feel the cracks or tell that the material (plastic or rubber) has hardened thus preventing it from properly sealing the opening. The flapper or stopper ball may also warp because of the effects of chlorine in the water which may not be detectable by touch. Sometimes you can tell if you raise and lower the flapper or stopper ball and let it drop. If it does not fall properly into the outlet, it may need to be replaced.

Tip: It is a good idea to take the flapper from your toilet to the hardware store or building supply outlet so that you can get the correct replacement. Each brand has slight but important differences.

When the water levels drops low enough, the fill valve will open and the tank will refill. The flapper serves the same purpose but is usually attached to tabs on the fill valve tube. The flapper is attached with a plastic or metal chain to the flush lever arm. As with the stopper ball, the plastic flapper may have deteriorated over time and may not seal off the opening properly. Replacing the flapper or stopper ball is not difficult to do, usually does not require any tools, and often solves the problem.

Tip: When replacing the flapper or stopper ball, be sure that the opening where they drop into is clear of debris or accumulated slime as this may prevent a good seal.

Tip: After replacing the flapper or stopper ball, you may need to slightly bend the flush lever arm to make sure it is lifting the flapper or stopper ball straight up. You may also need to adjust the length of the chain that connects the flapper with the flush arm.

Steps to replace a defective fill valve

You can sometimes tell if the fill valve is defective by lowering and raising the float thus turning the water on and off. If it does not turn off quickly when the float is raised, the washer inside the valve may have deteriorated. To replace a defective fill valve you must first turn the water supply off. Most often there is a shut off valve on the water supply line just where it comes out of the wall just below the tank. If there is no shut off valve or it does not totally shut off the water as can happen if the shut off valve was installed some time ago, you will have to turn off the water where the supply line comes into your house or apartment.

With newer fill valves, you can easily unscrew the valve assembly from where it attaches at the inside bottom of the tank by grasping the top of the fill valve and turning it counterclockwise. The replacement valve can be screwed into the threaded fitting at the bottom of the tank and hand tightened.

Tip: Be sure that the replacement valve is the correct height for the size of the toilet tank.

In many cases, you will need to detach the water supply line just below the bottom of the tank by loosening the connecter nut on the supply line with a channel lock pliers or adjustable wrench.

Tip: Some water supply lines are flexible and can easily be pulled away from the threaded end of the fill valve. Older installations may have a copper or brass connector line that can be slightly bent allowing it to be moved away from the fill valve line. Sometimes in doing so, the tube will be bent creating a "kink" in the tube. Moving it may also loosen the connection with the tube where it attaches to the shut off valve. You may want or need to replace the copper or brass line with a flexible line of the correct diameter which will be easy to install and less likely to leak.

Before removing the locking nut that holds the fill valve in place, you should remove as much water from the bottom of the tank as you can because when you remove the fill valve assembly, any water will run out of the tank onto the floor. To remove the hexagonal nut that secures the valve to the tank, turn it counterclockwise. Once this nut is removed, you can reach inside the tank and lift the valve and float assembly out of the tank. If you are replacing a valve that has a float attached to the shut off valve with a threaded rod as described above, you will most likely replace it with a newer style valve that has the shut off float that slide up and down the fill valve as described above. As mentioned before, be sure that the replacement valve is the correct height for the size of the tank. Tighten the nut below the tank being sure that the gaskets that seals off the opening inside and below the tank are in place. Then, reattach the water supply line and turn the water back on.

Tip: If you do not replace the water supply line from the valve to the tank, be sure the old washer or gasket has not deteriorated as this will cause it to leak.

Tip: Once the water line has been reattached, check for leaks. Usually, small leaks can be fixed by slightly tightening the appropriate locking nut.

Following these steps should fix any small leakage of water from the tank into the toilet bowl and reduce your water bill.

If you have any home repair questions, comments, or advice, feel free to post them on our Home Repairs Message Board.

services icon Looking for Help?

Join Our Mission

Help us expand our resources for people with vision loss.