What to Do When Your Toilet Overflow Won't Stop

white toilet sitting against a yellow wall
What You'll Need
New Floating Mechanism
Plastic Gloves
Towels or sponges

If you find that your toilet overflow will not stop running after you flush the toilet, then you may have a problem with the toilet water tank, or with the floating mechanism which shuts down your toilet tank overflow when the bowl has refilled. Before you give up and phone the plumber, you could save yourself a lot of money by trying to fix the problem yourself. If the toilet is filling until the water in the bowl is overflowing, then you need to take quick action to prevent your bathroom floor from being covered in toilet water. Prevent your floors from being damaged by fixing the toilet overflow system in your tank. Here’s how.

Step 1 - Remove the Toilet Tank Lid

When you are ready to begin, turn off the water supply which provides water for filling the tank. This is usually done by turning off a small knob just below the tank. Turn it clockwise to turn off the water. You may also turn off the main water supply outside if you cannot find or reach this water overflow knob. Once the water is turned off, flush the toilet once or twice to remove the water which is in the tank. When you have done this, remove the toilet tank lid, and place it on a towel close by. Do not stand the lid in the bath, or on a window sill, as these porcelain lids break easily, and can be costly to replace.

Step 2 - Locate the Floater

toilet ballcock or floater

Once you have removed the lid, then you will need to find the floater. This is usually a rubber ball about the size of a person's hand in most older models of toilet, and a large vertical column which is fitted to the toilet tube in the newer models. When you have found the floater, you will then need to find the device which controls how high or low the floater sits in the water. This is usually just a small clip which holds the ball in place, although newer models may have a series of switches which control the movement of the column.

Step 3 - Adjust the Mechanism

Once you have located the floater and the mechanism, you can arrange it so that the floater sits lower in the toilet, thus limiting the toilet overflow mechanism. If you are concerned that the floater is damaged or not working properly, remove it using your screwdriver, and replace it with a new floater. You should adjust the settle the mechanism as required, and turn the water back on. Flush the toilet, and watch as the toilet overflow gets to work. The water in the bowl should stop filling up more quickly, and the line of water inside the tank should be lower. If there is still too much water entering the tank, you should lower the floater mechanism again until you are satisfied that the toilet overflow is now working at its correct levels.