How to Stop a Running Toilet

Why This Matters

• A running toilet can waste hundreds of gallons of water per day, driving up utility bills.
• The fix is usually simple and requires only basic tools.
• Learning this repair saves money and builds DIY confidence.

Tools & Materials Needed

• Adjustable wrench or pliers
• Screwdriver (if needed for tank parts)
• Replacement flapper, fill valve, or float (depending on the issue)
• Towel or sponge (to soak up water)

Step-by-Step Instructions

1. Remove the Tank Lid
• Carefully lift the porcelain lid and set it aside.
2. Identify the Problem
• Flapper not sealing? Water leaks into the bowl.
• Float set too high? Water keeps filling past the overflow tube.
• Fill valve faulty? Water doesn’t shut off properly.
3. Check the Flapper
• Push down on the rubber flapper.
• If the running stops, the flapper is worn and needs replacing.
4. Adjust the Float
• For ball floats: bend the arm slightly downward to lower water level.
• For modern cup floats: slide the clip down the rod to adjust.
5. Inspect the Fill Valve
• If adjusting the float doesn’t help, the fill valve may be faulty.
• Replace it by disconnecting the water supply, unscrewing the old valve, and installing a new one.
6. Test the Toilet

• Flush and watch the tank refill.
• Ensure water stops at about 1 inch below the overflow tube.

Common Mistakes to Avoid

• Forgetting to shut off the water supply before replacing parts.
• Setting the float too low, which causes weak flushes.
• Not cleaning mineral buildup around the flapper seat.

When to Call a Pro

• If the toilet continues running after replacing the flapper and fill valve.
• If you notice cracks in the tank or unusual noises from the plumbing.

Print-Friendly Checklist

• Remove tank lid
• Identify problem (flapper, float, fill valve)
• Adjust float or replace flapper
• Replace fill valve if needed
• Test flush and water level

Here’s the labeled diagram of a toilet tank.

This visual pairs perfectly with your “How to Stop a Running Toilet” guide:

• The flapper shows where leaks often occur.
• The float highlights how water level adjustments work.
• The fill valve explains why water keeps flowing.
• The overflow tube sets the safe water height.