Fixing a Running Toilet

Welcome to the Koopman DIY Projectbook! This time around we’ll be taking a look at how to fix a running toilet. There are few things in life more irritating than a toilet that runs constantly. It might be the literal definition of flushing money down the drain. The good news here is that it’s (usually) a very easy thing to fix! With a little problem solving, a good local hardware store (such as Koopman Lumber), and some basic tools you can get your toilet back to normal working order in no time.


Koopman-Toilet-Color-CodeThe toilet is one item most people take for granted–until it stops working. Let’s discover what makes it all work. All you have to do is open the lid of your toilet tank and flush. When you do this watch the way everything interacts. When you push down on the handle (1) it lifts a chain (2) which is attached to the flapper (3). The flapper is raised allowing the tank full of water to slide down into the bowl.  As the water drains, the flapper slowly closes stopping the flow of water.

While all this is happening the float (4) off on the side is rising and falling with the water. The float is connected to a valve (5) that lets water into the tank when down, and stops the flow of water when up. The float should stop rising and shut the water off about an inch below the top of the overflow tube (6) Toilet Assembly Kit Koopman.

All of this works together to make a single flush.


The next time you use your toilet and flush it, wait around to hear if it keeps running after the point when it should have stopped. Inspect the following pieces and ask yourself:

  • Is anything visibly broken?
  • Is the flapper all the way down? Did it get stuck?
  • Is the chain on the flapper caught?
  • Is the water above the overflow pipe?

These questions will narrow the problem down to three parts, the flapper, the float, or the chain. Anything visibly broken  should be taken care of immediately. Otherwise turn off your water and get ready to do some fixing!


Koopman Toilet Flapper and Chain Assembly

Flapper and Lift Chain

Probably the most frequent cause of running toilets is the flapper. Take a good look at it after a flush as see what it’s doing. Is it getting caught on something or is it just not fitting in the hole anymore? Are there any tears or deteriorated parts? If it looks like the flapper is the culprit then this is an easy fix.

Start by turning off the water supply valve, removing the tank cover, and flushing the toilet to drain water from the tank. Then remove the flapper from the bowl by removing the back half from the pegs on the overflow pipe, and removing the chain from flush lever. Once you’ve removed the flapper valve take it down to your local Koopman Lumber store to ensure you’re purchasing the correct kit, and then take it home to reinstall. Start by attaching the back of the flapper to the pegs on either side of the overflow tube, and then attach the lift chain to the flush lever. Secure the flapper valve and turn the water back on. Your toilet should be back in working order now! When the tank fills up, give it a flush just to ensure everything is working perfectly, then replace the tank lid and enjoy your functioning toilet.


If the chain is broken then your best bet is to buy a new flapper kit and replace the whole unit (as detailed above). If it’s a bit long and getting caught or not pulling the flapper up all the way you can tighten the slack on the chain until there is almost no slack. This will ensure the flapper raises and lowers properly.


Koopman Float and water intake assembly

Float and Water Intake Assembly

Sometimes the float will need to be adjusted if the water is too high (and draining into the overflow pipe). Most filler assemblies will have a small screw on the side of the float that is adjusted to raise or lower the float, or have a clip on the side that stops it in a particular place. You will want to adjust the float so that the water comes up to an inch below the opening of the overflow pipe.


If everything is old and worn, you might have to replace the entire fill valve. This isn’t that hard but it does take a little bit more time than the other things we’re covered so far. Most fill valves will need to be replaced within 5-10 years of installation.

Shut off the water to the toilet and flush the water out. Then place a plastic container under the water supply hose and unscrew the hose from the tank body. Once the water is drained out use an adjustable wrench to unscrew the lock nut from the shank. With the nut removed you should be able to pull the whole assembly up and out of the toilet. The tank will drain into the plastic bin, and you will want to place the old assembly in the bin as well as it may continue to drain. Take the new fill valve and adjust the height to best fit the tank (usually about 1 inch below the top of the tank) and place the threaded end into the tank. Thread the lock nut by hand under the tank and use your slip joint pliers to give it another quarter turn. Screw the water supply hose back onto the fill valve shank. Replace the reflow tube into the overflow tube, making sure it doesn’t extend below the water line. Most kits will come with an angled plastic piece with a metal clip that you can feed the reflow tube into (after cutting it down) to ensure this isn’t a problem.

Once this is all set turn on the water and you’re good to go! Give it a practice flush to ensure everything attached properly.



Fluid Master Complete Repair Kit at Koopman Lumber

Sometimes, when you replace one old part, you find that the new one doesn’t quite fit with all the other old parts. For situations like those, we recommend the FluidMaster® Complete Toilet Repair Kit. It includes all the parts for the inside of your tank.

Toilets are an easy beast to manage once you know what you’re doing, and once you’ve done it you’ll never forget how. Thanks for reading this DIY project book! We hope you enjoyed it and as always, feel free to reach out to us with any questions. you can stop by one of our many Koopman Lumber locations or visit us online at www.koopmanlumber.com  with any additional questions!

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