A toilet that keeps running is usually caused by a worn or warped flapper, a flapper chain that is too tight or too loose, a faulty fill valve, or a float set too high. Replace the flapper and adjust the float first, since that fixes most cases; if water still runs into the bowl or overflow tube, the fill valve typically needs replacing. Fix it quickly, because a running toilet can waste hundreds of gallons a day.
Common causes
- Worn or warped flapper not sealing
- Flapper chain too tight or tangled
- Float set too high (water spills into the overflow)
- Faulty or worn fill valve
- Mineral buildup on the valve or seat
Steps to try, and when to call us
- Lift the tank lid and watch where water keeps moving.
- Check the flapper seals fully; replace it if worn or warped.
- Adjust the float so water stops below the overflow tube.
- If water still runs, replace the fill valve.
If you replace the flapper and fill valve and it still runs, or the leak is at the base, call First Response for same-day plumbing repair in San Antonio.
Frequently asked questions
How much water does a running toilet waste?
A running toilet can waste hundreds of gallons a day, which shows up fast on your water bill, so it is worth fixing right away.
Is a flapper an easy fix?
Often yes, it is a low-cost part. If replacing the flapper and adjusting the float doesn't stop it, the fill valve or a hidden leak is the issue.
Water on the floor around the toilet, what now?
That is a different problem, usually a wax ring or supply line, and should be checked quickly to avoid floor damage.