Toilet won't stop running after I flush. How do I fix it fast?

Concerns & risks

You flushed, washed your hands, and walked away, but the toilet is still roaring a minute later. You jiggle the handle and it stops, then it happens again next flush. It feels like you're babysitting a toilet, and you just want it to behave.

A non-stop running toilet can waste a huge amount of water in a single day.

Causes & evidence

The water level is set higher than the overflow tube, so the fill valve never gets the signal to stop. See the fill valve and overflow tube.

What to do

1. Lift the lid. If water is spilling into the overflow tube, the float is set too high.
2. Modern fill valve: turn the adjustment screw or slide the clip so the float sits lower.
3. Old ball float: gently bend the metal arm down a little.
4. Flush and check: the water should stop about 1 inch below the top of the overflow tube.

Common mistakes: People often bend the float arm randomly until the noise stops, then wonder why the bowl barely refills. Adjust in small steps and check the water line against the fill mark inside the tank. Another mistake is forgetting to shut off the supply valve before taking parts out. Then you get a surprise shower. If the handle chain keeps snagging, trim it rather than tying knots that catch under the flapper.

Speed Man tip: If it still won't shut off at the right level, the fill valve is worn. A universal replacement is cheap and comes with instructions.

Wrap-up: If water pours into the overflow tube, the float is set too high. Lower the float until water stops about 1 inch below the tube. Still running? Replace the fill valve.