Why Does My Toilet Keep Running?

Nine times out of ten, a toilet that won’t stop running has a worn flapper, the rubber seal at the bottom of the tank. When the flapper quits sealing, water leaks into the bowl, the fill valve keeps topping the tank off, and the cycle never ends. It sounds harmless, but a running toilet can waste 200 gallons a day, and you will see it on the water bill.

Check the Flapper First

Lift the tank lid and press down on the flapper with a stick (tank water is clean, your hand works too). If the running stops, you found the problem. Flappers warp and pick up mineral scale after a few years, and hard water speeds that up. If scale is eating a flapper every couple of years, a water softener helps every rubber part in the house last longer.

A new flapper costs a few dollars at the hardware store. Shut off the supply valve, flush to empty the tank, unhook the old one, and snap the new one onto the same pegs. Check the chain while you are in there. Too short and it holds the flapper open a crack, too long and it slips underneath and breaks the seal.

Look at the Fill Valve and Float

If the flapper seals but water keeps trickling down the overflow tube, the fill valve is set too high or has failed. The water line should sit about an inch below the top of the overflow tube. Most modern fill valves adjust with a screw or a clip on the float. If the valve hisses, sputters, or never quite shuts off after you adjust it, it is done. Replace it.

When It’s More Than a Five-Dollar Part

If you have swapped the flapper and the fill valve and the toilet still runs, the flush valve seat is probably pitted or cracked, and fixing that means pulling the tank. On a toilet from the 1990s or earlier, price that repair against a new toilet. Today’s models clear the bowl on 1.28 gallons; the old ones needed 3.5.

Summit Plumbing has been fixing toilets in Springfield, Riverton, Lakeside, Cedar Grove, Maplewood, and Fairview since 1985. If yours won’t stop running, or it’s clogged on top of it, call (555) 123-4567 and a licensed plumber will sort it out.