How to Fix a Toilet That Runs On

Repairing a run on Toilet is an EASY do it yourself fix!

This is what you see when you look down into your typical toilet tank. The yellow thing at top left is the flush valve also known as a “ballcock”. The gray thing in the middle is the flapper valve. By the way, despite the rust stains in these pictures, the water in the toilet tank is completely clean. This is not a nasty job.

Typical supply connections.

The water drops that you can see in some of these pictures is condensation that is agravated by the toilet running on. The constantly refreshed cold water in the supply lines, tank and bowl causes lots of condensation. This is not a good thing.

The first step of this repair is to turn off the water. Then flush the commode and hold down the handle to allow as much water as possible to drain out of the tank. If water still runs in (even very slowly) after turning off the supply tap under the tank then you need to find the main water shut off valve for your house and turn off the water there. Any time you turn off all water preasure to your home you should first turn off the electricity to the water heater to avoid burning out the top element. After turning off the water you need to remove as much water as possible from the tank. The easiest and fastest way is to use a wet-or-dry shop vac, but sopping it up with a rag works just as well.

Remove the supply line from the toilet flush valve. There is usually no need to unhook the line from the supply tap. By the way, the slip joint pliers in this picture is the only tool used in this repair. You might want to put a towel on the floor under the connection to catch any water you missed in the previous step.

Remove the water line from the stand pipe. Some toilets will have a retainer clip here.

After unhooking the supply line remove the flush valve retainer nut.

You are now ready to remove the old flush valve.

Remove the old flapper valve. In this case the flapper connects to ears on the stand pipe, but sometimes it slides down over the stand pipe.

You are now ready to install the new parts.

This is the kit that I used for this article. This type of kit is typical of what is available at any home improvement center. It’s a “Korky” brand “quiet fill” kit which was about $10, but other companies such as Fluidmaster make similar high quality kits.

Here’s what you get for ten bucks. A new flush valve complete with water line, clips, retainer nut, seal, and supply nut and supply seals. Plus a new flapper valve. I didn’t use all of the small parts BTW.

Here is the old flush valve on the left and the new one on the right. Installing the replacement parts is pretty much just the reverse of removing them. But remember Don’t ever tighten anything. It’s easy to come back and re tighten, but if you break something it means another trip to Lowes.

The new flapper is made so that it will work on any normal commode, but in this case the ring that is made to slide down over the stand pipe has to be cut off before use.

The flapper installs by slipping the brackets over the ears on the stand pipe.

The flapper chain needs to be adjusted to be as short as is practical. If the chain is too long it can cause either of two problems 1) The chain won’t lift the flapper high enough from the seat for it to float up and the toilet will make a noise like it is clearing it’s throat, but it won’t really flush. 2)The toilet will flush fine but the flapper will sometimes hang on the too-long chain and the commode will run on until someone “jiggles” the handle.

Sometimes the supply stop will leak around the stem after you have used it. If this is the case then you usually just need to tighten the packing nut that the stem goes through.

After you’ve installed the new parts and turned the water (and the water heater) back on.

Check for leaks

With the lid still off, flush the commode and make sure that everything works

You will probably have to adjust the water fill level according to the instructions that came with your particular kit

A lower water level will help to conserve water, but at some point the toilet will no longer flush completely

If water runs over the top of the stand pipe the water level is too high (Duh)

If water does not run over the top of the stand pipe, but the toilet still runs on, then check that the flapper is lined up correctly and the chain isn’t too short