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How to Fix a Running Toilet

How do you fix a running toilet? 

If you’re like me then this problem drives you bonkers. But fortunately, the solutions are super simple.

And you need only 3 tools (Phillips head screwdriver, flathead screwdriver, & wire snips) and 15 minutes to do this project.

You’ll also reduce your water bill in the process which is always nice.

Hey, that’s money you could use toward the movies – who doesn’t love Paul Rudd? (And he’s a Steeler’s Fan, booyah!!)

Alright, enough with the movie references let’s get your toilet fixed and stop your water bills from skyrocketing.


Toilet Anatomy and Physiology: Good Stuff to Know That’ll Impress Friends

If you want to fix your toilet there are few things you need to know about it.

You’re gonna get pretty up close and comfortable with it. So knowing a toilet tank’s anatomy is kind of important.

Toilets have a fill valve, flush valve, and flapper.

Fill valves (you guessed it) fill the toilet tank with water. Here in the states they’re located on the left of the tank and have a water supply line connected to them.

Fill Valve

Fill valves also have some type of float that goes up or down. When you flush the toilet water leaves the tank and goes down into the bowl.

The float drops. Then the fill valve refills the tank with water and the float rises along with the water level. At a certain point, the float will stop and trigger the fill valve to stop the refill process.

Flush valves are in the center of the tank. When you flush a toilet the flapper rises and allows water to leave the toilet tank via the flush valve and go down into the toilet bowl.

Flush Valve

The sudden rush and weight of the water leaving the tank moves the pee or poo (just keeping it real) from the toilet bowl and into your home’s sewer pipes.

Now you know the basic function of your toilet.

Don’t be grossed out by the water in the tank. It should be clean. Unless you have a chlorine cleaning tablet in the tank. In which case the water has chlorine in it.

As a side note, I don’t recommend you put cleaning tablets in the tank because they can corrode the tank’s parts and CREATE leaks!!

Culprit #1: Old FLAPPERS

Every time I say flapper it just cracks me up. I mean who came up with the name (if you know the answer add it to the comments).

Nonetheless, this little piece of rubber that sits on the flush valve can go bad very easily. Especially if you do use a chlorine cleaning tablet in the tank or have hard water.

The flapper creates a seal with the top of the flush valve. If this seal is bad then water will leak from the tank.


If water leaks from the tank, the float on the fill valve will go down until it triggers the fill valve to refill the tank with water.

This problem is easy to fix.

You need to remove the flapper and inspect it for any humps (don’t laugh, this is the best description I could come up).

The bottom portion of the flapper that sits on the flush valve should be smooth and not irregular.

Identify what brand of toilet you have: American Standard, Kohler, etc.

Turn the shut-off valve clockwise. This turns off the water supply to your toilet.

Flush the toilet and hold down the handle until most of the water is gone. Then remove the flapper and take it to the hardware store with you.

Buy a new flapper that fits your brand of the toilet and matches the one you’re holding in your hand. It’ll cost about $5.

Replace the Flapper

Super cheap.

Easy to do.

Will stop a running toilet.

Culprit #2: Long Flapper Chains

I’m a fan of Mr. T but long chains aren’t cool in toilet tanks.

When you flush a toilet the handle is connected to the flapper with a chain.

Sometimes this chain is WAAAAAAY too long.

And as a consequence, the chain gets stuck between the flapper and the flush valve. Thus, the flapper can’t create a good seal with the flush valve, and water leaks from the tank.

Trim Long Chains

Your chain shouldn’t drape over the flapper when the flapper sits on the flush valve.

To solve this problem move the clip that connects the chain to the toilet handle further down the chain. This will reduce the length of the chain. You can then cut off the excess chain with wire snips.

Culprit #3: Too Much Water in the Tank

If your tank always sounds like water is draining from it chances are the tank’s water level is too high.

The ideal water level in your tank should be 1/2 to 1 inch below the overflow pipe. Make a mark on the overflow pipe with a Sharpie marker to indicate the maximum water level in the tank.

You change the water level in your tank by adjusting the float on the fill valve.

There are several different types of floats. All you need to know is that if you raise the float you raise the water level in the toilet tank. If you lower the float you’ll lower the water level in your tank.

In my video, I show you how to adjust three different kinds of floats. I think you’ll like the video because it’ll walk you through this adjustment as well as the prior two fixes discussed above.

Some floats have a screw that can be turned counterclockwise.

This lowers the float down into the tank’s water.

Other floats have plastic hollow balls on the end of their float arms.

You can bend metal float arms to get the float further down into the tank water.

Sometimes though, the float arms are plastic. In this case I’d bet my kids piggy bank money you can adjust a screw on the fill valve that’ll get the float lower.

And in turn, your tank’s water level won’t overflow into the overflow pipe.

Culprit #4:  Bad Fill Valves

If you’ve tried all these fixes and you STILL have a toilet tank that runs then replace the fill valve.

This costs all of $10.

Replace Fill Valves

And it’s way easier than you think. Although the directions for most fill valves are PAINFUL to read.

Would it kill the manufacturers to throw in a joke or two?

Replacing a toilet fill valve takes 10-15 and will save you $50 to $75.

Alright, these are 4 ways to fix a toilet that keeps on running.

I wanted to share them with you so that you don’t feel overwhelmed when doing this repair.

Here’s a supply list to help you out

Trust me, eventually, you’ll hear a toilet run in your house. It’s like Murphy’s Law, if it can happen it will and likely on Sunday during a holiday weekend when plumbers are on vacation and you’re entertaining house guests.

Before I forget here’s a quick story. One of my tenants called last fall and said he kept hearing the toilet run. So ran over to the house and checked it out. I don’t know how long this was happening but the flapper somehow developed a nice bump in it. As a consequence, the water in the tank kept leaking into the bowl.

Needless to say, the water bill for that month was $116. 

Yeah, I almost fell over because the bill is typically around $25.

What’s Next

Learning how to install a water shut-off valve is equally important – replace old valves if they don’t work.

If you’re doing a bathroom remodel and need help, join one of our online courses – they’ll make your bathroom renovation much easier!

Let me know if you have any questions and I’ll do my best to help.

Thanks as always for reading, watching, and being part of our awesome community.



Fix Running Toilets