a toilet in a bathroom

Why Your Toilet Won't Stop Running

A toilet that won't stop running is usually caused by a faulty flapper, a stuck fill valve, or an incorrect water level in the tank. These problems keep water flowing continuously from the tank into the bowl, wasting gallons of water a day and increasing your utility bill. The good news: you can usually fix it yourself with a few simple steps.


Why Your Toilet Keeps Running After You Flush

Here are the most common reasons your toilet won't stop running, along with how to fix each one:

1. Worn or Misaligned Flapper

The flapper is the rubber seal at the bottom of the tank. Water will continuously leak into the bowl if it's cracked, dirty, or doesn't sit properly.

How to fix it:

  • Turn off the water at the shutoff valve (usually behind the toilet).

  • Flush to drain the tank.

  • Inspect the flapper. If it's warped or hard, replace it with a new one (they're inexpensive and sold at any hardware store).

  • Make sure the flapper seals fully over the valve seat.

2. Faulty Fill Valve

The fill valve controls when the tank stops filling with water. If it's stuck open or clogged with debris, water keeps flowing.

How to fix it:

  • Remove the tank lid and inspect the fill valve as the tank refills.

  • The valve is likely the issue if the water level never stops rising or flows into the overflow tube.

  • Adjust the float arm (or float cup) lower, or replace the fill valve if it's worn or corroded.

3. Chain Too Tight or Tangled

The chain connects the flush handle to the flapper. If it's too short or gets caught under the flapper, the seal won't close.

How to fix it:

  • Adjust the chain length so there's a little slack.

  • Make sure it isn't getting stuck under the flapper after a flush.

4. Water Level Set Too High

Water will keep draining into the bowl if the tank fills above the overflow tube.

How to fix it:

  • Adjust the float (ball or cup) lower using the screw or sliding clip on the fill valve.

  • Aim for the water level to sit about 1 inch below the top of the overflow tube.

5. Damaged Float

A cracked or waterlogged float may not rise properly to shut off the fill valve.

How to fix it:

  • Inspect the float for cracks or damage.

  • Replace if it's not floating correctly or has water inside.


Step-by-Step: How to Fix a Running Toilet

If you're not sure where to start, follow these steps in order:

  1. Turn Off the Water
    Twist the shutoff valve behind the toilet clockwise until the water stops.

  2. Remove the Tank Lid
    Set it aside carefully on a soft towel or mat.

  3. Flush the Toilet
    This empties the tank so you can inspect the parts.

  4. Check the Flapper
    Make sure it's sealing fully. If not, clean around the valve seat or replace the flapper.

  5. Inspect the Chain
    Adjust for the right length—there should be a bit of slack when the flapper is closed.

  6. Adjust the Float
    Use the fill valve's screw or clip to lower the float. Refill and check the water line.

  7. Test the Fill Valve
    Turn the water back on and let the tank refill. If it still doesn't stop, the fill valve may need replacing.

  8. Replace Parts If Needed
    If flapper or fill valve replacements are needed, most hardware stores carry universal kits that are easy to install with basic tools.

  9. Flush Again and Observe
    Once the water is back on, flush and confirm that the tank fills and shuts off as usual.


Still Won't Stop Running? Time to Call a Plumber

If your toilet still runs after replacing the flapper and adjusting the fill valve, the problem may be deeper, like a cracked overflow tube or a hidden leak. That's when it's best to call a licensed plumber.


Expert Toilet Repairs in Metro Atlanta

If you're in the Atlanta area and your toilet won't stop running, RooterPLUS! is here to help. Our experienced plumbing team can quickly identify and fix the issue, whether it's a bad flapper, worn-out valve, or something more complex.

We also fix:

  • Toilets that won't flush

  • Slow-filling tanks

  • Leaky toilet bases

  • High water usage problems

Call us today or schedule online for fast, professional plumbing service.