Kohler Toilet Running Intermittently or Leaking Water

Last Updated on September 19, 2022 by Alex Cubias

A leaky toilet can be annoying to have in your home with it constantly turning on and off and filling your home with noise. It can also be expensive, with leaky toilets being able to leak around 200 gallons of water a day. You want to fix a leaky toilet as quickly as possible before you get a massive utility bill.

Kohler toilets “run” when unnecessary water is filling the tank and “leak” when water is leaving the tank and filling the bowl of the toilet. Both are often easy fixes usually related to faulty parts letting water escape through the toilet. Repairs can be performed with bare hands and minimal tools.

While it can seem complicated, it is quite easy to fix a leak on a toilet. Here are some tricks that might help you and suggestions for how to diagnose the problem with your Kohler toilet.

How to Determine the Issue with Your Toilet

While you might know that something is wrong with your toilet, you might not be sure what it is. While a running toilet or a leaking toilet might seem similar, there is a subtle difference between the two. While both are due to water getting loose in your toilet, the location that the water is escaping through is the most important part. With that in mind, here are some things that may help you determine the issue with your toilet.

Is there water running into the bowl of your toilet? If you can see water running into the lower area, or if the water is rippling, it is likely that you have a leak in your toilet.

On the other hand, is there water filling the tank, but no water is flowing into the bowl? You may want to remove the lid on the back tank. While the lid is removed, is there water overflowing into the overflow area around the fill valve? Can you see any debris within the tank that may be trapped in the toilet’s valves and seals? If you can see any of these things, you likely have a running toilet tank.

If your toilet isn’t leaking water quickly enough for you to observe, you may need to take a longer step. Find a time where you won’t need to use the toilet for several hours, for example overnight. Take the lid off of the water tank and mark the water level in the tank. Turn off the valve connecting the water line from the wall to the toilet. Wait 6-8 hours before coming back. Check the chart below to figure out how to proceed.

Change in Water LevelWhat It Means
No ChangeThere is an issue with your fill valve on the left side of the tank. No leak in the tank.
Water only at Flapper or Seal LevelThe flapper or seal is worn and needs to be replaced. A leak from the tank to the bowl.
Tank completely emptyThe gasket at the bottom of the flush valve needs to be replaced. A leak from the tank to
the bowl.
Tank partially emptySlow leak from the tank into the bowl. May be caused by a cracked flush valve.

How to Repair a Running Toilet

By testing your toilet by following the steps above, you should have found out which category your toilet falls into. Only one of these categories is caused by your toilet running—the first one. If your toilet tank maintains its water level even when the water is turned off, there is likely an issue with your fill valve. Fixing this is simple; you will just need your hands and a plastic cup.

Take the cover off the water tank and turn off the water line. The fill valve should be near the top on the left side of the tank. To remove the valve cover, press down and turn like you are taking the lid off of a medicine bottle. Take the rubber seal out of the valve and wash it in your sink. If this seal is cracked, it may need to be replaced.

Take your plastic cup and cover the bottom portion of the fill valve. Turn the water line on and let the line wash out (the cup will prevent water from spraying everywhere.) Turn the water off after about a minute, replace the rubber seal, and reattach the top the same way you removed it.

Check out the video from Kohler below if you are more of a visual learner.

How to Repair a Leaking Toilet

If your toilet matches one of the other three categories from the chart above, you have a leak in your toilet. Unlike a running toilet, the issue here is that your tank is leaking water. A couple of parts can cause this issue.

The first part to check is the flapper or seal. This is the part on the bottom of the tank that covers the drain. When you flush, this flapper is lifted, and the tank empties into the bowl of the toilet. If the water in the tank is running down to the level of the flapper, it may be cracked or not closing all the way after flushing.

Kohler recommends checking the chain connecting the flapper to the handle to make sure it has enough length to close all the way. If the flapper is damaged, make sure to replace it.

If instead the entire tank was drained after the test, the gasket below the flapper is damaged and needs to be replaced. Remember, a leaky toilet can cost you gallons of water a day, so don’t brush off a leaking toilet.

How to Find Kohler Toilet Parts

If you have a leaking or running toilet, you may need to replace some of its parts. Here are some ways to find replacement parts for your Kohler toilet:

By going to the Kohler website and imputing the name of your toilet, you can find the individual parts that you will need. If you are unsure which part you may need, you can also check the Kohler parts catalog. If your toilet is less than a year old, it may still be under warranty. If you think your toilet may be under warranty, you can check the warranty details.