DIY Tip: How To Fix a Running Toilet

A running toilet not only wastes a lot of water but the constant sound can also drive you a little crazy.

This problem can waste more water than a tap leak, which in turn can waste your money.

Luckily, hissing toilets usually come with simple solutions.

What you’ll need:

  • A towel
  • Gloves
  • A bucket
  • A flashlight

Step One: Shut off the water.

The water valve will be connected to what looks like a hose under your toilet and leading into the floor or wall.

Turn the valve to shut off the water, but do not over-tighten.

Most of them are quarter-turn stops and don’t even require a full turn to cut the water.

You may hear the hissing stop when the water is off.

Step Two: Place the bucket or pan under where the hose meets the toilet & slowly disconnect the slip joint.

There should be a little water falling out, but if it should not be spraying. If it’s spraying, you haven’t turned the water off completely.

Quickly turn the stop to cut the water completely.

Place the hose somewhere out of your way.

Lift the back off of the toilet and place it somewhere safe.

Step Three: Check the flapper.

Lift it and see if the flush valve has any cracks or damage.

If this is the case, you’ll need to buy a new flush valve.

Step Four: Check the fill valve.

You should be able to easily disconnect it by removing a small hook or snap that connects the screw at the bottom to the valve.

The screw controls the water level for the flush valve.

Step Five: Lift the top piece off of the fill valve.

This piece is called the diaphragm valve.

Pull the diaphragm valve apart and inspect the screw and pin it inside.

Clean the diaphragm valve thoroughly.

Step Six: Use a flashlight to look down into the fill valve.

There may be something obstructing the fill valve.

If you believe this is the case, reconnect the hose and just barely turn the water back on enough to flush out the clog.

You may want to block the top with your hand or a towel to keep the debris from flying out, or to prevent water from spraying when the clog is clear.

Step Seven: Put the diaphragm valve back together.

Make sure to match the pin back to the center.

Step Eight: Put the diaphragm valve back on the fill valve.

Turn it back into place and reconnect the hook or snap that connects it to the screw at the bottom.

If this doesn’t work, then you need a new fill valve.

Step Nine: Reconnect the hose and turn the water back on to determine whether the problem has been solved.

You should be good to go at this point. If it’s still running, then you probably need a professional plumber at this point.

We hope that helped you save a few dollars and put an end to that maddening and costly running water.

For lots more info on the most common toilet problems and their solutions, see our main toilet repair and installation page.

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Owner - Operator at RT Olson Plumbing
Bob Olson has over 18 years experience in all aspects of residential and commercial plumbing. He's a 4th generation plumber. With over 500 five-star customer reviews, he runs one of the best-rated plumbing companies in Corona, CA.
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