Running toilet — skip tank tablets that can wear the flapper
Running toilet
Running toilet tip: some drop-in tank cleaning tablets can soften or warp the rubber flapper over time. Clean the bowl instead and keep the tank plain.

If your toilet keeps running months after a new flapper, look at what sits in the tank. Some drop-in cleaning tablets can wear down rubber parts over time.
Keep the tank plain for a quiet, non-running toilet
- Lift the tank lid and check for a drop-in tablet or a cleaner holder.
- Remove it and let the tank flush clear a few times.
- Feel the flapper. If it is soft, sticky, or out of shape, plan to replace it.
- Clean the bowl with a regular bowl cleaner instead of anything that sits in the tank.
That is the beat: plain water in the tank is kinder to the flapper and can stop a slow running toilet from coming back.
More help
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- Related fixes elsewhere: Refrigerator water filter — wet the O-ring before you seat it · Humidifier wick — do not leave a descaling tablet in storage