Step 1: Identify the Problem

The first step is to figure out what’s causing the problem. Is it a leaky flapper? A busted fill valve? Is the flapper chain just stuck? Or did your toddler throw their toy down the toilet again? Take a deep breath and lift the lid off the tank. SOME toilets have different mechanisms but for the sake of this project we’ll assume you have a traditional fill valve/ flapper combination.

Check the Flapper

The flapper is the little rubber thingy that controls the water flow from the tank to the bowl. It’s usually connected to the flush lever with a chain. Sometimes the fix is as simple as freeing the chain from whatever it is stuck on. If the rubber flapper is damaged or worn, it can cause the toilet to run. Don’t worry, this is an easy fix. First you’ll need to shut off the water at the valve on the wall behind the toilet. Next, just remove the old flapper and replace it with a new one. There are a few different mounting types so make sure you check how it mounts on the hinge side. Often times ones that say “Universal” don’t match the universe you’re living in! Once you replace it, turn the water back on and give it few test flushes to make sure it’s still not leaking.

Inspect the Fill Valve

“Okay, what’s a fill valve?” The fill valve is responsible for refilling the toilet tank with water after you flush. If it’s not working properly, it can cause the toilet to run continuously. Usually a fill valve has a float on it which triggers the water to turn on and off. If the float is stuck down or damaged, the water won’t know when to shut off. To check it, lift the float mechanism up and down (with the water on). If the float is in the down/lowest position, it should call for water. It should shut off at its upper position. (You can adjust the height of the fill valve float on most assemblies) Flush the toilet and test the float and also listen for any hissing sounds that aren’t caused by running water. If you hear anything unusual, it’s time to replace the fill valve.

Check for Leaks

If the flapper and fill valve are working properly, it’s time to check for leaks. Add a few drops of food coloring to the back of the tank and wait for 30 minutes. If the water in the bowl changes color (without flushing), that means there’s a leak somewhere in the tank assembly or bowl. That may require removing the tank off the toilet base and doing some further inspection for worn seals/gaskets.

Make the Repairs (DIY, Baby!)

Now that you’ve identified the problem, it’s time to make the necessary repairs. Whether it’s replacing the flapper or the fill valve, or fixing a leak, you got this. You’re a DIY master! And if all else fails, it’s time to call in the big guns – a professional plumber. But seriously, you got this. Here’s how you can do it.

How to Replace a Toilet Fill Valve

Step 1: Turn Off the Water Supply

At the wall there should be a water shutoff valve of some kind. It may be a modern quarter turn, or an older shutoff of some kind. Make sure you turn off the water supply before moving to the next step.

Step 2: Flush the Toilet and Disconnect the Supply Hose

The water supply hooks to the toilet with a flexible water line. Use your hand or a pair of channel lock pliers to remove the water line from where it is attached to the toilet. (This is the bottom of the fill valve) Keep a bucket or towel nearby to catch any water that didn’t drain from the toilet tank or water line when it was disconnected.

Step 3: Remove the Retaining Nut

Most of the time there is a retaining nut and flexible washer holding the fill valve in place (right by where the water line attached). Use the pliers if you have to to loosen the nut and remove the nut from the bottom (the rubber washer is usually inside the tank and will lift out with the assembly). Some water from the tank may come out of the hole in the bottom. This is normal as the tank rarely empties fully on a flush. The fill valve assembly should now be loose.

Step 4: Lift the Fill Valve Assembly from the Tank

Disconnect any additional flexible hoses from inside the tank and lift out the fill valve assembly. It should come out easily. If not, double check you’ve removed any locking nuts.

Step 5: Replace with New Fill Valve Assembly

The new fill valve assembly should go right back into the same spot and install in the reverse order of the removal. Follow the instructions on your new valve to adjust the float height, and determine how much water to use per flush. Most adjust easily with a retaining clip or by twisting the riser up or down.

Step 6: Re-Connect the Water Line

Reinstall the locking nut on the underside of the toilet tank, making sure the rubber gasket is installed on the bottom of the new assembly. Make sure the fill valve assembly is not turned against the inside of the tank and it can move properly up and down. Then secure the lock nut and washer in place. Reconnect the water supply line and turn on the water to test and make sure everything works properly.

Step 7: Enjoy Your Throne!

This part is pretty self explanatory.

There you have it, a DIY guide on how to diagnose and fix a running toilet. Don’t let a little running water ruin your day. You can fix this yourself. Good luck!

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