A running toilet can quickly drive up your water bill while creating an annoying sound in your house. This article will walk you through the steps on how to stop a toilet from running. Chances are the fix is easier than you think and can be done with a few basic tools. In this guide, you’ll learn how to diagnose the problem and fix it step-by-step.
Most running toilet problems are caused by a faulty flapper, improperly adjusted float, or worn fill valve. Learning how to stop a toilet from running can save water, reduce utility bills, and prevent unnecessary wear on your plumbing system.
A good practice to get into is whenever you are going to the hardware store to get a replacement part, it’s important to bring the old one with you. This will help ensure you are getting the equivalent replacement. Put the old part in a small sandwich bag to avoid getting your car or clothes messy.
Understanding Why Toilets Run: The 3 Main Causes
The reasons for a toilet to run can be separated into three categories. Understanding the type of running sound your toilet makes can help you narrow down the problem faster.
Runs Constantly
With this situation you will be hearing the sound of water flowing to the tank at a continuous pace. If you lift the lid you will likely see water movement in the bowl as well. This movement may be very faint, and hard to tell at first.
The most common reason for this is that the float is set too high. There are different styles of floats that are adjusted in slightly different ways. This is an easy fix that requires tools you most likely already have. More on this later.
Runs After Flushing
After the toilet is flushed the water is running for a longer period than normal, but ends up stopping. It’s something that isn’t always noticed, but can cause the household water use to go up dramatically.
The most common reason for this is that the flapper isn’t sealing properly after the flush. Something is causing it to be suspended in the water column for a bit longer than usual. There are a couple of reasons for this you can investigate.
Runs Randomly
A randomly running toilet isn’t as easy to notice as the other two. That’s mainly because since the running happens at odd times, you aren’t always nearby.
If your toilet runs randomly throughout the day, the flapper or flush valve is usually leaking slowly.
Parts of a Toilet Tank You Need to Know
There are a few important parts of a toilet you will need to know in order to diagnose the issue. All of these parts are found in the tank which is above the toilet bowl, near the bathroom wall. Lift the lid to the tank and place it aside while you look inside.
Fill Valve
The fill valve is the vertical tube that allows water to enter the tank from the supply line. This is a combination of several different parts that are used for the function of filling the tank and shutting the water off when finished. There are several different fill valve designs, but all have the same basic parts.
Float
The float is a piece found on the fill valve used to tell it when the water reaches the right height. Once there, a stop mechanism shuts off the water to the tank. One reason for a toilet to ruin is if the float gets stuck too high.
Overflow Pipe
The overflow pipe is what allows excess water to exit the tank before spilling onto the bathroom floor. If the water level gets too high, excess water flows into the overflow pipe instead of spilling onto the bathroom floor.
Flapper
The flapper is a rubber piece that gets lifted when the toilet is flushed, allowing the tank water to flow to the bowl. After the flush is finished it seats back down, creating a watertight seal that lets the tank fill back up. A faulty or dirty flapper is capable of causing a running toilet.
Flush Valve Gasket
The gasket is located between the flush valve, and the tank. It is a rubber gasket that creates a watertight seal. This piece may get cracked and brittle over time. When this happens the toilet can run constantly. Replacing the flush valve gasket is the most complex fix for a running toilet.
Handle and Chain
The handle connects to the flapper via a chain. When the toilet gets flushed, this lifts the flapper, allowing water to flow into the bowl. Sometimes if the chain gets caught, twisted, or tangled it may hold the flapper in the up position. This can cause the toilet to run constantly after the flush.
How to Diagnose Your Running Toilet
A running toilet gives clues about what’s wrong. There is a lot to learn from the sound and timing of a run. The good news is that most toilet repairs are inexpensive and can be done with common household tools.
Sometimes a leaking toilet isn’t obvious at all. In the past I’ve found out about my toilet leaking from a ridiculously high utility bill. To figure out where the leak was coming from, I used a toilet leak detection dye packet.
After putting the dye tablet in the toilet tank I waited 10 minutes. This turned the water in the tank blue, which leaked into the bowl. Once the bowl started to show blue, it told me there was a leak. If you use one of those blue toilet bowl cleaners, take it out and flush the toilet a few times to clear the water beforehand.
Lift the Tank Lid
Set the lid aside and look at two things. First check if the water level is around one inch below the top of the overflow tube. If it’s above the top and spilling over, adjust the float down to the right height. If that’s not the issue, lift the flapper and check its condition. Sometimes algae buildup on the underside of the flapper can cause it to leak water. Wipe this off with a rag and then listen for leaks.
The Running Sound
Listening to the sound can tell you a lot. If you hear a hissing sound this may mean water is trickling into the bowl through the flapper. Try lifting the flapper up and feeling around the base for any cracks or anomalies.
A “whoosh” sound every 20-30 minutes may be from a leak in the flush valve. This causes the float to drop low enough to trigger the fill valve to refill the tank. The fix for this is usually replacing the flush valve gasket or the entire flush valve assembly.
Inspect the Fill Valve
If the flapper wasn’t the issue, watch what happens to the fill valve after a flush. What should happen is it will open once the float drops, pumping water into the tank. The flapper will seat itself, then the water will fill up until the float is at the correct height. Two common fill valve problems are a float that gets stuck and an internal valve seal that has worn out or cracked.
Check the Float Position
The float will rise with the water, and drop when the toilet is flushed. Sometimes when the toilet has been used for a while the float works itself out of adjustment. It should be set to the height where the water stops around one inch below the top of the overflow pipe.
How to Adjust the Toilet Float
Adjusting the float is a simple fix. When a toilet runs constantly, the float is often adjusted too high, allowing water to continuously spill into the overflow pipe. This prevents the fill valve from shutting off properly.
If your toilet has an older ball-style float on a metal rod, gently bend the rod downward slightly to lower the water level. This will cause the float to sit a bit lower in the tank. Small adjustments are all you need.
If it’s a float that slides along the overflow pipe, you can adjust it by turning the screw. Make sure the float moves down when you turn the screw. There is a chance you may need a screwdriver or pliers to do this.
The target water level when the water shuts off should be between ¼ and 1 inch below the top of the overflow pipe.
If Toilet Keeps Running After Flushing, Check the Flapper
If the flapper isn’t falling shortly after the flush it may be a problem with the chain. In this case check for kinks that need to be straightened out. If the flapper is seated, there may be some algae buildup or cracks on the underside. Clean the underside with a rag and test the toilet again. If there was buildup under there, this fix should be considered temporary as it will be a matter of time before it happens again.
The best long term fix for this issue is to replace the flapper. To do this, start by shutting the supply line off at the wall. Remove the old flapper by pulling forcefully away from the flush valve. Once it’s removed, take it to your local hardware store to find a replacement. You can also order a compatible replacement flapper online. Make sure you get one that’s compatible with your toilet brand.
If the Toilet Runs Randomly, Replace the Flush Valve Gasket
If the toilet is running randomly, one possibility is the flush valve is not working correctly. They get old and brittle, allowing water to flow from the tank into the bowl. Because this gasket sits between the tank and flush valve assembly, this repair is more involved than the other fixes in this guide. You’ll also need a few basic plumbing tools for this repair.
Required tools: Adjustable pliers (channelock pliers or crescent wrench), screwdriver, sponge, small bucket
To remove the old gasket you will need to first remove the tank. Start by shutting off the water supply line to the toilet. Flush the toilet once to empty the tank. You will then want to try to remove as much water with the sponge as you can.
There are either two or three bolts below the tank that need to be removed. Hold the nut on the underside of the tank with the pliers, and turn the head inside the tank counterclockwise with the screwdriver. Disconnect the supply line using the adjustable pliers.
After the tank is disconnected, gently lift it straight up to dislodge it from the bowl and remove it from the toilet. Lay it on the ground on its back.
The flush valve has another nut on the underside of the tank that needs to be removed. After this nut is free the valve can be removed from the tank.
The flush valve gasket is at the base of the flush valve making contact with the inside of the tank. This gasket can be slid off the valve and replaced with a new one that is compatible.
Button Flush Toilets
The button flush toilet is built differently. The brand of the toilet matters for how to disassemble it. Check your toilet manufacturer’s instructions for troubleshooting steps specific to your model. Since button flush systems vary by manufacturer, detailed repairs are outside the scope of this guide.
Once you find the part that is the issue you will be able to look for compatible toilet replacement parts.
When to Replace the Toilet Entirely
There comes a point when the toilet is too far gone to try to fix it. Continuing to repair an old toilet can eventually become more trouble than it’s worth. It’s not worth replacing one part only to have another go bad soon after.
Read my post on How to Install a Toilet for a complete breakdown on this process. You will get a complete understanding on what goes into changing a toilet. It’s easier than you think!
Frequently Asked Questions
Why is my toilet running?
There are three main areas to check when a toilet is running. These are the flapper, the fill valve, and the float. The first two areas are rubber seals that block water from entering the bowl. When this rubber fails it causes the toilet to run. The float can also cause problems if it moves out of the correct position.
How do I fix a running toilet?
The first step to fixing a running toilet is to diagnose the problem. A dye test can help you hone in on the issue. Work through the troubleshooting steps above to identify and fix the issue methodically.
How much water does a running toilet waste?
A constantly running toilet is capable of wasting up to around 200 gallons per day. Water and sewer costs vary by location, but a constantly running toilet can significantly increase your utility bill. This doesn’t include the increase in household sewage cost. Over time, a single running toilet can waste thousands of gallons of water and add hundreds of dollars to your utility costs. That’s more than the cost of a new toilet, and much more than the replacement parts cost.
Why does my toilet keep running after flushing?
If the toilet keeps running after a flush, the most likely problem is the fill valve is struggling to shut off. Common causes include a dirty or worn flapper, a chain that is too tight or tangled, or a float that has moved out of adjustment.
When should I call a plumber instead of fixing it myself?
If you can identify if the solution is a flapper replacement, float adjustment, or fill valve swap out, all of these are simple DIY projects you can do. If you are having trouble with the diagnosis part of the process a professional may be helpful. Another issue is if you are having trouble with an old shut off valve that won’t turn off all the way. This would require water to the house to be shut off completely.
Conclusion
Fixing a running toilet is one of the most beginner-friendly plumbing repairs for a DIY homeowner. You don’t need any special tools, and the ones you do need are probably in your garage. When going through the steps to finding and fixing this issue, be methodical and take your time. Since there are only a few common causes, a step-by-step approach will usually help you find and fix the issue quickly.
Thanks for reading Remodel Upgrade. If this guide helped you fix your running toilet, check out our other bathroom repair and plumbing DIY tutorials.
Thank you for reading this article. Here at Remodel Upgrade I am dedicated to helping you create your sanctuary.
You got this,
Kevin
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Kevin
I grew up in a family where my dad and several uncles were general contractors. They took me to the jobsites, and also taught me so much about home maintenance. I remember spending several summers in high school helping my father build houses. It gave me so much knowledge that I am excited to share!
