Why Does Your Toilet Keep Running? Causes and Fixes

A running toilet is more than just an annoyance—it’s a significant source of water waste. According to the Environmental Protection Agency (EPA), a running toilet can waste up to 200 gallons of water per day! Identifying and fixing the issue quickly can save you money and help conserve water. Let’s dive into the most common causes of a running toilet and how to address them.

1. Faulty Flapper

The most common cause of a running toilet is a worn or malfunctioning flapper. The flapper is the rubber or plastic seal at the bottom of the toilet tank that controls the release of water into the bowl. Over time, flappers can warp, crack, or lose their seal.

Solution: Inspect the flapper for visible wear and tear. If it looks damaged or doesn’t create a proper seal, replace it with a compatible flapper from your local hardware store.

2. Incorrect Water Level

If the water level in the tank is set too high, it can continuously overflow into the overflow tube, causing the toilet to run.

Solution: Adjust the water level by lowering the float in the tank. This can usually be done by turning the adjustment screw on the fill valve or gently bending the float arm downward.

3. Malfunctioning Fill Valve

The fill valve controls the flow of water into the toilet tank after a flush. If it’s damaged or not shutting off properly, the tank may overfill, leading to a running toilet.

Solution: Test the fill valve by flushing the toilet and observing its operation. If it’s faulty, consider replacing it with a new anti-siphon fill valve for better efficiency.

4. Chain Issues

The chain connecting the flush handle to the flapper can sometimes get tangled or caught, preventing the flapper from sealing completely.

Solution: Ensure the chain has enough slack to allow the flapper to close fully but isn’t so loose that it gets caught under the flapper. Adjust the chain length as needed.

5. Worn Overflow Tube

The overflow tube directs excess water from the tank to the bowl. If it’s cracked or damaged, it can cause the toilet to run.

Solution: Inspect the overflow tube for cracks or leaks. If necessary, replace it with a new tube that fits your toilet model.

6. Sediment Buildup

Over time, sediment and mineral deposits can build up in the toilet tank, affecting the operation of the fill valve and flapper.

Solution: Clean the inside of the tank by turning off the water supply, draining the tank, and scrubbing away sediment with a non-abrasive cleaner.

How to Test for Hidden Leaks

Not all toilet leaks are immediately obvious. Use this simple method to check for hidden leaks:

• Add a few drops of food coloring to the tank water.
• Wait 15-30 minutes without flushing.
• Check the bowl for traces of color. If you see any, there’s a leak between the tank and the bowl.

When to Call a Professional

If you’ve tried the solutions above and your toilet still runs, it may be time to call a professional plumber. Persistent issues could indicate a more serious problem, such as a damaged flush valve seat or internal tank damage.

At ABC Plumbing, Sewer, Heating, Cooling, and Electric, we specialize in diagnosing and repairing all types of plumbing issues, including running toilets. Call us at 888-868-6667 in Chicago or 813-452-5952 in Florida for fast, reliable service.

ABC Plumbing Locations

Also check the following blog post: What Causes Pink Stains on Toilets and Bathtubs.