How to Stop a Toilet That Keeps Running

A toilet that keeps running can be annoying, wasteful, and costly. The constant noise of water flowing down the bowl can drive you crazy, and the extra water usage can really add up on your utility bills over time. Fortunately, fixing a running toilet is usually a pretty straightforward DIY project.

In this comprehensive guide, we’ll cover common causes of toilets that keep running and detail step-by-step instructions for how to stop a toilet that keeps running. Read on to learn how to diagnose and resolve this common household plumbing issue.

What Causes a Toilet That Keeps Running?

There are a few main culprits that can cause a toilet to continuously run water after flushing:

Flapper Valve Issues

The flapper valve at the bottom of the toilet tank is designed to seal off the flush valve after a toilet is flushed, stopping the flow of water from the tank to the bowl. If the flapper valve is misaligned, cracked, or otherwise faulty, it may not create a tight seal. This allows water to continuously leak from the tank into the bowl, creating that running water noise.

A worn-out flapper valve that has become brittle or misshapen over time is the most common cause of a toilet that keeps running. Replacing the flapper valve is generally an easy and inexpensive fix.

Problems with the Float Ball or Fill Valve

The float ball and fill valve work together to refill the tank after a flush. If either of these toilet tank parts become corroded or misadjusted, it can cause the tank to overfill and water to run into the overflow tube. This creates the running water sound.

Issues with the fill valve not shutting off properly or the float ball getting stuck in the raised position can both lead to overfilling and running water. Adjusting the float ball height or replacing the fill valve are usually straightforward repairs.

Tank Lever Issues

The toilet tank lever is connected to the flapper valve at the bottom of the tank. When you push the lever down to flush, it lifts the flapper and releases the water. If the chain connecting the lever to the flapper valve gets caught or damaged, it may prevent the flapper from fully closing. This would cause a constant flow of water from the tank into the bowl.

Inspecting the chain and reconnecting the lever is often all that’s needed to fix tanks with lever-related running issues. Replacing a broken or obstructed chain can also easily resolve this problem.

Step-by-Step Guide to Stop a Running Toilet

Now that you know what may be causing your toilet to keep running, here is a step-by-step guide to fixing it:

Step 1: Turn Off the Water Supply

Before making any repairs inside the toilet tank, you’ll need to shut off the water supply. Locate the water shutoff valve on the wall behind or beside the toilet and turn it clockwise until it’s completely closed. This stops water from refilling the tank so you can work safely.

Step 2: Flush to Empty the Tank

With the water shutoff closed, flush the toilet to empty all of the water out of the tank. Sponge up any remaining water in the bottom of the tank.

Step 3: Check the Flapper Valve

The flapper valve at the base of the tank is secured to the flush valve with a chain. Gently lift the flapper and inspect its condition.

Check for the following issues:

  • Cracks, pits, or tears in the rubber indicating deterioration
  • A loose seal with the flush valve allowing water to leak through
  • Misalignment preventing the flapper from sealing properly

A misshapen, cracked, or otherwise faulty flapper valve that cannot seal will cause continuous running water. Replacing the flapper is generally an easy, inexpensive fix.

Step 4: Test the Flush Lever and Chain

While the tank is empty, manually lift the flapper valve and make sure it drops back down into a sealed position when released. Then flush the toilet by pushing down the tank lever. Make sure the chain connecting the lever to the flapper isn’t stuck or catching.

If the flapper doesn’t fully close when you manually release it, or the flush lever chain is obstructing it, make adjustments as needed so the flapper can properly seal against the flush valve when at rest.

Step 5: Check the Float Ball

With the tank empty, check that the float ball is set to the proper water level height and can move freely up and down the fill valve shaft.

Hold the float ball at the top of the shaft and let go – the water level mark on the float should align with the water line mark on the fill valve. If not, adjust the float clip until it stops at the right spot. Make sure the float isn’t catching on anything and can move smoothly.

Step 6: Check the Fill Valve

Inspect the fill valve for damage and mineral deposits. Give it a light clean by wiping away any grime buildup. Make sure the water supply line is securely connected.

Then, hold the float at the proper water level and turn the water supply back on. As the tank fills, check that the fill valve completely shuts off the water when the float ball reaches the preset level.

If water continues running into the overflow tube, there is an issue with the fill valve closing. This will require replacing the fill valve.

Step 7: Reinstall Tank Parts

Double check that any tank parts you removed are properly reinstalled, aligned, and functioning correctly. The flapper valve should create a tight seal when at rest on the flush valve. The fill valve should shut off completely when the float reaches the set water level.

After reinstalling the tank parts, turn on the water supply and allow the tank to fill completely to confirm there are no leaks and all parts operate as intended.

Step 8: Make Final Adjustments and Test

Once you’ve identified and fixed the problematic component(s), do a final test flush and inspection. Verify that:

  • The flapper fully seals against the flush valve after flushing
  • The fill valve completely shuts off when the float reaches the proper water level
  • The tank lever chain is not obstructing the flapper
  • No water continues running into the overflow tube

If you have any persistent running water sound or leaks, recheck your repairs and make additional adjustments. Keep fine tuning until the toilet flushes and refills silently as normal.

FAQs About Fixing a Toilet That Keeps Running

What if adjusting the flapper valve doesn’t fix the running water?

If you’ve replaced the flapper valve and made height adjustments but water still leaks through the flush valve seal, you may need to replace the entire flush valve mechanism. while less common than a faulty flapper valve, deterioration or mineral deposits around the flush valve seat can prevent the flapper from fully sealing and cause running water.

Why does my toilet run intermittently?

An intermittent running toilet that turns on and off irregularly is usually caused by a partially obstructed or clogged fill valve. Tiny particles and mineral deposits can get lodged in the fill valve, preventing it from fully closing. This allows water to trickle through. Try cleaning the fill valve or replacing it to resolve an intermittent running issue.

How can I tell if my toilet is losing water?

If you aren’t hearing water running but suspect your toilet is leaking, check your water bill for spikes in usage. Then do a dye test: drop a dye tablet or a few drops of food coloring into the tank and wait 10-15 minutes without flushing. If color appears in the bowl, you have a small leak. Inspect the flapper valve and fill valve to find the source of the leak.

Why does my toilet run for several seconds after flushing?

It’s normal for a toilet to run for 5-7 seconds after flushing as the fill valve refills the tank. But if it runs for 30 seconds or longer before shutting off, you likely have an issue with the fill valve or float setting. Adjust the float so it stops the water at the proper preset level. Clean and check the fill valve for obstructions.

What causes the toilet to run periodically when not in use?

This is usually caused by a leaky flapper valve or improperly set float. A bad seal on the flapper allows water to continuously drip into the bowl, then the fill valve refills the tank when it hits a certain low point. Tweak the float setting and replace the flapper valve to resolve this.

Preventing Toilets That Keep Running

A little preventive maintenance can help keep your toilet operating smoothly and silently for years to come. Here are some tips:

  • Regularly check the toilet parts – Do quick visual inspections of the flapper valve, chain, and fill valve every few months to check for early signs of wear or issues.
  • Replace the flapper valve proactively – Don’t wait for leaks to replace an old flapper. Replace it every 3-5 years as preventive maintenance.
  • Clean the toilet valves – Use a rag and non-abrasive cleaner to remove mineral deposits and debris from the flush valve, fill valve, and flapper to prevent buildup and obstructions.
  • Use toilet tank cleaner – Add a tank cleaner tablet to the toilet tank to help prevent sediment or grime buildup that can cause running issues.
  • Tighten water connections – Check that the water supply line connections under the toilet tank are snug and leak-free.

Taking a few minutes for regular toilet tune-ups and staying vigilant for any signs of trouble can help you avoid ending up with a toilet that annoyingly runs all night long. Act quickly when you first hear constant water flow problems to prevent wasted water and money.

When to Call a Plumber

While the majority of constant toilet running issues can be fixed with easy DIY repairs, there are times you may need to bring in a professional:

  • If replacing multiple times parts can’t resolve the running problem
  • For problems with in-wall or in-floor plumbing lines causing flow to the toilet
  • If the toilet bowl rocks or the base is corroded, indicating a need for replacement
  • For houses with old galvanized plumbing lines that may require overhaul
  • If the water supply valve itself is leaking and needs replacement
  • For complicated repairs like replacing a broken toilet tank

Have a plumber handle any issues that are beyond your skill level. Professionals have specialized tools and knowledge for addressing complex toilet repairs or full installations.


Dealing with the constant noise of a toilet that keeps running can quickly become aggravating. But in most cases, you can resolve a running toilet yourself following the steps in this guide.

The most common culprits are worn flapper valves and malfunctioning fill valves – both inexpensive parts to replace. Adjusting the tank components and conducting regular maintenance checks can also help prevent annoying toilet running issues before they arise.

With a few handy troubleshooting tips, a little patience, and some replacement parts when needed, you can get even the noisiest running toilet fixed in no time. Just be sure to turn off the water supply before sticking your hands in the tank for repairs. Your toilet will be flushing and filling as silently as ever.