Why Does My Toilet Keep Running?

When a toilet starts running and doesn’t stop after the normal flush cycle, people often stare blankly at the tank wondering what the problem is, or jiggle the flush valve to see if that fixes anything. While those solutions won’t do you any good, there are a few simple things you can do to fix a running toilet. The first step is to determine the cause, and then you can act accordingly to stop the toilet from running.

Toilets that keep running may have one of the following problems:

• The float height needs to be adjusted 
• The flapper is leaking and needs to be replaced
• The refill tube needs to be shortened

Tools and materials you may need:

• Rubber gloves
• Replacement fill valve
• Toilet replacement parts
• Multi-bit screwdriver
• Cutting pliers

We strongly advise that you contact an expert plumber to inspect the situation for you, as there could be other issues with your toilet that may need repair and maintenance. However, that doesn't mean that you can't inspect your toilet yourself! Here are some things that you can do to help fix your running toilet in the meantime.

1. You Need to Lower the Float

Among the most common causes for a running toilet is overflow water leaking down into the bowl from the tank via the overflow tube. This happens when there's too much water in the tank. You can adjust the water level by adjusting the height of the float.

To lower the water in a toilet with a float arm, loosen or tighten the screw until the float arm lowers.

To lower the water in a toilet with a column float attached to the fill valve, loosen the screw or clip, push down the float, and tighten everything back up again.

2. The Flapper Is Leaking and Needs Replacing

Perhaps the most common reason for a running toilet is an old flapper that needs to be replaced. When flappers get old, they don’t seal the way they should, and this allows water to pass constantly from the toilet tank into the bowl.

To replace the flapper, simply remove the old one and replace it with a new one from the hardware store. Remove the old one by detaching the chain and taking the flapper off the pins on the side of the overflow tube. To attach the new one, connect the chain and attach the sides to the pins.

Tip: Drain the water from the tank before you replace the flapper. Shut off the water supply to the toilet, and then flush the toilet to drain the water.

Tip: If the chain is too long on the new flapper, you may need to shorten it. If it’s long enough to get caught underneath the flapper, you won’t get a good seal, and the toilet will continue to run.

3. You Have to Shorten the Refill Tube 

Another cause behind your running toilet could be that the refill tube is always pumping water into the bowl, and this happens when the tube is too long and isn't positioned properly in the overflow tube.

To shorten a refill tube, pull the tube out of the overflow and hold it just above the opening of the overflow, trim it off there, and clip it to the side of the overflow tube to keep it in place.

Note: The reason this causes the toilet to run is that the refill valve will create a suction effect that pulls water out of the fill valve.