How to Fix a Running Toilet in 6 Simple Steps

It’s time to cross “fix the toilet” off your to-do list

A woman holding down the toilet handle
Photo: Titykul_b / Adobe Stock
A woman holding down the toilet handle
Photo: Titykul_b / Adobe Stock
Stephanie Mickelson
Written by Stephanie Mickelson
Contributing Writer
Updated May 28, 2024
SKILL LEVEL
Simple
COMPLETION TIME
2 hours
COST
Up to $25
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What you'll need:
TOOLS
  • Wrench
  • Bucket
  • Sponge
SUPPLIES
  • New flapper (optional)
  • New fill valve (optional)
  • Diluted vinegar (optional)

Weak flush? Running water noises? Increased water bill? Chances are you have a running toilet—one of many common toilet problems that are easy to fix. Use this guide to learn how to repair a constantly running toilet and bring down those utility costs.

Prepping to Fix a Running Toilet

A running toilet happens when water constantly moves through it, even when it’s not in use. Aside from the sound of running water, you can tell you have a running toilet issue if you’re experiencing the following:

  • Having to hold the handle down for the toilet bowl to empty

  • Having to jiggle the handle to get it to stop running

  • The toilet randomly flushes on its own

  • Leaking water on the sides of the toilet

This plumbing issue has three causes: problems with the overflow pipe, the flush valve, or the fill valve. 

Luckily, learning how to fix a running toilet is relatively easy, even without plumbing experience. However, if you aren’t careful, you can make the situation worse. If you’re feeling uncomfortable tackling this yourself, don’t risk it. Hiring a professional plumber now may save you money in the long run. 

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  1. Turn Off the Water

    To shut off the water to the toilet, locate the shut-off valve behind the toilet. Turn the valve clockwise to shut it off.

  2. Check for a Leaky Fill Valve and Fix It

    The fill valve controls the amount of water going to your toilet from your house’s water supply. If this valve leaks, water will likely continue flowing into the toilet without stopping. Thankfully, each toilet has an overflow tube that redirects excess water, preventing your toilet from overflowing. 

    To see if a leaky fill valve is the culprit, lift the tank lid and look for debris and calcium buildup in the valves.

    If you need to replace your fill valve and would like to install it yourself, follow these steps:

    • Collect a sponge, a wrench, and a bucket.

    • Empty the toilet tank by shutting off the water supply and flushing the toilet. Use your sponge to soak up any remaining water.

    • Install the new fill valve according to the manufacturer’s instructions.

    • Turn the water supply back on.

  3. Adjust the Fill Height and Check the Float

    The float, or float cup, is attached to the fill valve and moves up and down on the tower to signal the fill valve to shut off when the tank's water level reaches the correct level. You can adjust the fill height by twisting the adjustment rod that moves the float up and down. The tank's water level should be about 1 inch below the top of the overflow tube.

  4. Check and Adjust the Flapper Chain

    If the flapper chain is too long or too short, it can cause problems with flushing. If it’s too short, it won’t allow the flapper to seal properly. If it’s too long, it won’t allow adequate time for a full flush and can become tangled. You can adjust the flapper chain by adjusting the link attached to the clip on the flushing lever.

  5. Test the Flapper

    The flapper is part of the flush valve system, which controls the flow of water by opening the flapper when the toilet is flushed and closing the flapper after flushing. 

    Inspect the flapper for signs of wear, tear, and debris buildup that may prevent it from fitting correctly inside the flush valve and potentially cause your toilet to run. 

    If you find debris buildup, clean the flapper using diluted vinegar. However, if there is visible wear, you may need to replace your toilet flapper.

  6. Test Flush

    Once everything is fixed and replaced, do a test flush. Leave the tank open to make sure everything is filling and draining. After flushing, wait about five to 10 minutes to monitor for any phantom flushing or continuously running water.

DIY vs. Hiring a Pro to Fix a Running Toilet 

Fixing a running toilet is a relatively easy task. The more you know about how a toilet works, the easier this job is to tackle on your own. However, if this is your first attempt to fix a plumbing problem, this DIY might take longer since you’ll learn as you go. 

The cost of repairing your toilet varies depending on the materials you need (a fill valve costs $8 to $10 and a flapper costs $5 to $10), your location, and whether you hire a professional. Hiring a plumber costs $45 to $150 per hour. Call at least three toilet repair pros in your area for estimates. 

Paul F. P. Pogue contributed to this piece. 

Frequently Asked Questions

The most common reasons a toilet won’t stop running are a faulty flapper or fill valve, improper fill height, or incorrect chain length. Luckily, all these issues are relatively easy to fix with parts you can find at a local hardware store. You can also call a plumber or toilet repair professional to solve the problem.

If your toilet won’t stop running, you might have a bad fill valve. This may be the case if the valve has calcium or debris buildup, is cracked, or shows visible signs of wear and tear. A bad fill valve may also be the culprit if you’ve already checked the flapper and chain and adjusted the fill height to no avail.

To keep your toilet in good working order, replace the toilet fill valve every five years. Toilets get quite a workout, so while toilet maintenance may not be on top of your to-do list, it’s essential to keep up with it to ensure your toilet is in good working order and ready when needed.

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Learn more about our contributor
Stephanie Mickelson
Written by Stephanie Mickelson
Contributing Writer
Stephanie Mickelson is a freelance writer covering home improvement, real estate, design, and personal finance. Before beginning her freelance career, she worked in residential construction, specifically remodeling kitchens, installing cabinets, flooring, countertops, trim, and more.
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