If your toilet runs continuously but the water never reaches the top of the overflow tube, then adjusting a toilet flapper is your first item to check.
This article will discuss the most persistent problem with toilet flappers and how to fix it.
Table of Contents
What’s the Problem?
So, why do we want to check the toilet flapper first? It’s simple. We see one problem over and over. Thankfully, it’s an easy one to fix.
Your toilet flapper is probably misaligned with the flush valve seat that it sits on. The flapper (or stopper) needs to sit perfectly on the valve seat (also called a valve or flapper gasket) for the toilet to stop running.
Here’s how it works. When it is raised up, water gets flushed. When it goes back down, it creates a watertight seal on the flush valve seat.
If the seat is misaligned as we suspect, it won’t create that watertight seal, and water will continue flowing. So, the first attempt at a solution is to adjust the flapper’s guide arm. If it continues to run after this, the stopper may be worn or cracked and will need to be replaced.
Adjusting a Toilet Flapper in 6 Steps
All you need to do this job is about 20 to 30 minutes and the following tools: sponge, slip joint pliers, and a scrub pad.
- Begin by turning off the water supply valve. It is usually a round handle that can be found under the toilet tank, against the wall on the left side.
- Now, flush the toilet to empty the tank and sponge dry the tank.
- Look at the lift wire to see if it is bent. If it is, bend it straight again with your hands. The lift wire can be seen in the diagram below.
- Using your slip joint pliers, loosen the guide arm adjustment screw. Adjust the guide arm back and forth as necessary so it guides the flapper directly into the flush valve outlet. Then retighten the guide arm adjustment screw.
- Pull up the flapper and clean the inside of the flush valve outlet. Do this by scouring it with your scrub pad. We want to make sure the flapper and flush valve seat are nice and clean for a perfect fit.
- Finally, drop the flapper into position and turn on the water supply valve under the toilet tank.
PRO TIP: Sometimes, the problem is the float that’s attached to the toilet flapper chain. The float can be adjusted too. Here’s a video that explains this simple process.
What if the Flapper is Worn or Cracked?
While inspecting the toilet flapper, make sure it is not cracked or worn away. If so, you’ll need to move onto the next step: replacement. But don’t worry, we have some articles on how to do that too. See the “Resources” section below.
Here are some great resources for adjusting, fixing, and replacing a toilet flapper. Also included is an in-depth article on how to replace a toilet handle system (which can be a related problem).
- Leaking toilet flapper? Here’s how to fix it in 4 steps!
- Replacing a toilet flapper in less than 30 minutes!
- Toilet troubleshooting. 6 problems you can diagnose and fix.
- How to replace a toilet handle: a step-by-step guide
- My toilet flush is slow. How can I fix it?
- Easy way to fix an intermittently running toilet
Obviously, there are many reasons for a toilet to not work properly. So, being able to diagnose the problem is the first step.
For most DIYers, you’ll want to start by checking if your toilet flapper needs an adjustment. First, open the toilet tank, flush the toilet, and see if water never reaches the overflow tube. Then check the flapper. Does it seem to fit well on the flush valve seat?
If you see that one or both are issues, follow the instructions above for adjusting a toilet flapper in 6 steps.
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