Toilet Keeps Running? Here's How to Fix It

That constant hissing from the bathroom is money going down the drain. A running toilet can waste 200 gallons a day, and most of the time the fix is a five dollar part and twenty minutes of your time. Here is how to find the real cause.

Start with the tank lid

Take the tank lid off and set it somewhere safe. Those lids crack if you look at them wrong. Now watch what the water is doing. If water is flowing into the tall overflow tube in the middle, your water level is set too high. If the water level looks fine but you hear running, the flapper is leaking.

The flapper test

The flapper is the number one cause of running toilets. It is the rubber seal at the bottom of the tank, and after a few years it warps and stops sealing. Here is the test: put a few drops of food coloring in the tank water. Do not flush. Wait fifteen minutes. If color shows up in the bowl, the flapper is leaking.

Replacing it is easy. Turn off the water valve behind the toilet. Flush to drain the tank. Unhook the old flapper from the pegs and unclip the chain. Hook the new one on the same way. Turn the water back on. Done. The part costs about five dollars at any hardware store.

The fill valve

If the water never shuts off at all, even with a good flapper, the fill valve is the problem. That is the tall assembly on the left side of the tank. It wears out and sticks open. Same drill: water off, flush, unscrew the water line and the lock nut underneath, lift the old valve out, drop the new one in, reconnect. Twenty minutes, maybe twelve dollars.

Check the chain

Sometimes it is embarrassingly simple. If the chain between the flush handle and the flapper is tangled, or too long so it gets caught under the flapper, or too short so it holds the flapper open, you get a running toilet. Free fix. Adjust it so there is about half an inch of slack.

When to call a plumber

If the tank itself is cracked, stop and call someone. If you have replaced the flapper and the fill valve and it still runs, there may be a hairline crack in the overflow tube or a bad seat under the flapper, and that is plumber territory. But nine times out of ten, it is the flapper.