Fix a Toilet That Keeps Running

A running toilet wastes up to 200 gallons per day. 95% of the time it's one of three cheap parts — flapper, fill valve, or chain. Fix in under 30 minutes with no plumber.

Diagnose First (Free)

1. Remove tank lid and flush. Watch what happens.
2. Flapper doesn't seal? It's warped/deteriorated (most common). Water keeps trickling into bowl.
3. Water overflows into overflow tube? Fill valve won't shut off. Adjust float or replace valve.
4. Chain tangled or too tight? Flapper can't close. Adjust chain to 1/2 inch slack.

Fix: Replace Flapper ($5, 10 min)

1. Turn off water at shut-off valve behind toilet.
2. Flush to drain tank.
3. Unhook old flapper from overflow tube pegs.
4. Snap new flapper onto pegs. Hook chain with 1/2 inch slack.
5. Turn water back on. Test flush.

Fix: Replace Fill Valve ($15, 20 min)

1. Turn off water and flush to drain.
2. Disconnect water supply line under tank with adjustable wrench.
3. Unscrew lock nut holding old fill valve. Remove valve.
4. Install new valve per instructions (usually Fluidmaster 400A — fits 99% of toilets).
5. Reconnect supply line. Adjust float so water stops 1 inch below overflow tube.

When to Call a Plumber

If both parts are new and it still runs, you may have a cracked overflow tube or tank leak. Cost: $150-300 service call.

Pro tip: Add food coloring to tank. If it appears in bowl within 10 minutes without flushing, it's definitely the flapper. Replace it even if it looks fine — rubber degrades in 3-5 years.