Toilet Keeps Running! Fix it With This Easy Guide

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Toilet Parts

Your toilet flushes just fine, but it doesn’t know when to quit. Your toilet keeps running! Even when it occasionally stops, it eventually starts up again suddenly. No matter how often it occurs, it’s wasting a lot of water and making that noise that keeps you up at night. Fortunately, it’s usually not difficult or expensive to repair a toilet if you know a bit about how they work.

The Noisiest Toilet Ever!

Here’s a scenario almost everyone has experienced at least once: your toilet works, it just seems to be constantly running. Sometimes if you “wiggle” the handle, it will stop; other times, it keeps running forever. (Help!)

Not to worry! At Bob Oates Sewer & Rooter, we’re here to help you get to know what’s in your toilet tank and how it works. Mechanisms can vary from toilet to toilet, but they all work on the same principles.

How a Toilet Works

Pull the lid off of your toilet tank and flush a couple of times while you watch the process in the tank. With the tank lid off and notice the process. When you push the handle, the chain lifts a flapper, letting a tankful of water fall through the opening in the bottom, into the bowl. As the water level drops, the flapper drops and closes the opening. You should notice that when you push the toilet lever down on the outside, inside the tank, the lever is coming up. Attached to that lever is a chain that runs down to what is called the flapper. The flapper is a piece of rubber or plastic (and sometimes both) that makes a seal around the flush valve hole to keep the water inside of the tank.

As the chain lifts the flapper upright, the tank is allows the water into the bowl. Once the water has exited into the bowl and reaches a height above the trap in the toilet, the water will push everything through the trap and into the sewer.

The Toilet Float

You should also notice a tall, skinny mechanism with a “toilet float” or “float ball” attached. This is the fill valve. Just like the name says, the “fill valve” allows fresh water to fill in the tank again.

When you pushed the lever, the flapper came up and released the water. As the water left the tank, the toilet float on the fill valve drops, allowing the water to start filling in the tank. At the same time, the flapper will fall, re-sealing the exit hole.

As the water level rises in the tank, it pushes the toilet float or float ball up until it reaches the desired level. The fill valve then turns the water flow off. Of course, each manufacturer is a little different, but all the same principles apply universally. Once you figure out how things work “under the hood,” fixing them becomes much easier.

How To Fix a Toilet That Keeps Running

Now let’s take a look at how to fix a toilet that keeps running, starting with identifying the cause.

There are really only 3 reasons why a toilet is constantly running:

The Flapper is Stuck Open

Remember above how when you pushed the lever down it lifted the flapper to allow water to rush out of the tank? In some instances the flapper can get hung up on the chain and it does not re-seat on the flush valve. This causes the water to keep running out of the tank, and the tank will not fill and allow the toilet float to rise up and turn the water back off.

A Stuck Toilet Float or Float Ball

It can also get caught up or held down by something, unable to float up to the right level and turn off the water.

An Incorrectly Adjusted Toilet Float or Float Ball

In this case, the flapper comes down and re-seals over the flush valve and the float comes up. However, if incorrectly set, the water will spill into the overflow tube (which empties into the toilet bowl) and the fill valve will not shut the water off. For reference here, be sure to adjust the water level below the overflow tube at least 1 inch.

The best way to solve the problem of a constantly running toilet is to “catch it in the act.” If you’ve waited long enough after flushing and the toilet still hasn’t quit running, lift the tank lid and look in.

Here are the steps to take:

Close the Flapper

If the tank is not full and it is not filling, chances are that the flapper is stuck open. Reach in and close it with your hand. If it sticks repeatedly, look for the cause. Make any necessary adjustments.

  • Is the flapper catching on the chain?
  • Is the flapper wedged open on its hinge?
  • Is the flapper aligned with the opening?
  • Is the flapper simply just old and stiff (and needs replacing)?
  • If you have a ball seal instead of a flapper, is the wire that lifts the ball straight and does it move freely?

Adjust the Valve and Float

If the tank is full and the flapper is closed, and water is running over the top of the overflow tube, but the toilet hasn’t stopped running, first try adjusting the valve and float.

Pull Up on the Float With Your Hand

If this action stops the flow, then adjust the level of the float. No matter how you adjust the float, adjust it so the tank stops filling when the water is about an inch (2.5cm) below the top of the overflow tube.

Check for Excess Pressure

Excess pressure can cause a leaking flapper if the tank level is too high, even with a brand new replacement. If the float is around the valve post, pinch the metal clip and slide the float down on the wire. Make sure the float ball isn’t touching other objects — adjust it so it isn’t dragging against the side of the tank, the overflow tube, or anything else.

Make Sure the Float Ball Isn’t Leaking or Filling With Water

If you unscrew the float ball and hear water inside when you shake it, replace the float ball.

What if a Toilet Is Running Intermittently?

Now that you have a better idea how to fix a toilet that keeps running, there is one last symptom that is very common — that is when the toilet runs intermittently. The cause of this is almost always due to the flapper not making a good seal around the flush valve. The tank will fill and the water will shut off but the water will slowly leak through past the flapper.

When the tank water level drops, the float will also drop, allowing the fill valve to turn the water back on. This cycle will just keep repeating itself, costing you money each time it happens.

Here’s what you can do:

Replace the Flapper

If the toilet stops filling and then starts again intermittently, you have a slow leak. The most common cause of slow leaks is a leaky flapper. Over time, this inexpensive rubber part decays, or minerals build up on it.

Cleaning may work to remove mineral buildup, but it’s usually best just to replace the whole part. Take your old one with you to the hardware store for comparison to get the right size. To perform the replacement, simply close the valve sticking out of the wall under your toilet tank.

Flush the Toilet

If the valve is completely closed, the tank will not refill and you will not hear water running after the tank empties. Pop the old flapper off its hinges, disconnect it from the chain, and pop the new one into place. Run a finger carefully around the rim where the flapper seats. Remove any uneven buildup of minerals that might cause a leak.

While replacing the flapper use a sponge with bleach to clean the flapper seat. Try flushing a few times to make sure the chain is the right length for the new flapper — it should open when you push the handle and then drop closed all the way when the tank empties. You may have to trim and adjust the chain by trial and error. Also, make sure that the flapper aligns properly with the opening.


Following these guidelines will help you fix a toilet that keeps running — which will ensure you’re not flushing money down the drain!

At Bob Oates Sewer & Rooter, we’re available for you day or night. We offer emergency service & have qualified service technicians on-call & readily available.

Fill out our online form to schedule an appointment or call anytime — we’re here to help!

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