How to Fix a Toilet That Fills Every 15 Minutes

Servicing the toilet flapper should stop the toilet from refilling.

Servicing the toilet flapper should stop the toilet from refilling.

If your toilet keeps refilling at 15-minute intervals, it probably has a leak. In the vast majority of cases, the problem is with the flapper, which is the rubber seal between the tank and the bowl. When it's worn, or the chain is too short, water seeps into the bowl, and the fill valve cycles on as soon as the float falls below the cutoff level. There's a more serious possibility, however, and that is that the tank is leaking. If so, you'll see water on the floor. Some tank leaks require replacement of the toilet.


Look at the water in the toilet bowl. It should be still, but if the flapper is leaking, you'll probably see ripples caused by water flowing from the tank. You can confirm the leak by putting food coloring into the tank and waiting for a few hours. The bowl water will turn the same color.


Turn off the toilet shutoff valve and flush the toilet. Hold down the handle to empty the tank as much as possible.


Feel the flapper chain. If there is noticeable tension, it may be too short. Disconnect it and lengthen it by one or two links. Turn the water back on and let the tank fill. If the leaking appears to have stopped, you don't have to do anything else.


Empty the tank again if lengthening the chain doesn't stop the leak. Disconnect the flapper chain and remove the flapper either by unhooking its ears from the overflow tube or sliding the attached ring up and off the tube. Take it to the hardware store to find a replacement.


Install the new flapper by reversing the procedure for taking it off. Be sure to allow enough slack when you attach the chain, but don't allow too much, or the flapper may not lift all the way and the toilet won't flush.


Look for water seeping out of the tank if you notice water on the floor. If it's coming from under the tank, the bolts holding the tank to the bowl may be too loose, or the washers may be worn. Tighten each bolt by holding the head steady with a flat-head screwdriver and turning the nut under the tank with adjustable pliers. Don't overtighten. If the leak doesn't stop, you need to replace the washer.


Empty the tank and sponge out the water in the bottom. Loosen and remove each bolt and replace the rubber washer between the head and the bottom of the tank. Tighten the bolts and turn the water back on.

Things You Will Need

  • Food coloring
  • Flat-head screwdriver
  • Flapper
  • Adjustable pliers
  • 2 tank bolt washers
  • Sponge


  • If you see water seeping from a hairline crack on the tank, replace the tank or the entire toilet. You can't repair such leaks.
  • If you can't find a leak anywhere, the toilet fill valve may be defective. This doesn't happen often and can be remedied by replacing the valve.

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