2026-03-111 min read

Toilet keeps running: fix it in 10 minutes

A running toilet is usually a flapper, fill valve, or float adjustment. Here’s the quick, cheap fix sequence that works.

A running toilet wastes water and money, but it’s usually an easy fix.

1) Take the tank lid off and watch what happens

  • If water is going into the overflow tube nonstop: fill valve/float.
  • If the water level slowly drops then refills: flapper leak.

2) Fix the flapper (most common)

If the flapper is warped or slimy, it won’t seal.

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3) Adjust the float

Lower the float so the fill valve shuts off before water reaches the overflow.

4) Replace the fill valve if needed

If it won’t shut off reliably, replace it.

See top-rated options on Amazon for “toilet fill valve

When to call a plumber

If you see cracks in the tank/bowl or water around the base, stop and get help.

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