Why does my toilet keep running?

Wondering what's going on in there?

How your toilet tank works, in plain English

A toilet tank is like a small bathtub with a plug at the bottom and a faucet that shuts itself off when the tub is full.

Each number matches a step below. Push the handle and the chain lifts the flapper. Water drops into the bowl. The flapper falls shut, and the fill valve refills the tank until the float rises and shuts it off.

Here's what happens each time you flush:

You push the handle. The handle arm lifts a chain, and the chain lifts the flapper, the rubber plug at the bottom of the tank.
Water rushes into the bowl. It drops through the hole under the flapper. Pros call that hole and its hard ring the flush valve.
The flapper drops shut. As the tank empties, the flapper falls back onto its ring and seals it.
The fill valve refills the tank. This tall post on one side lets fresh water in. A small refill tube also sends some water down the overflow tube to refill the bowl.
The float shuts the water off. A plastic cup or ball rides up with the water. When it's high enough, it closes the fill valve. A short refill after each flush is normal.
The overflow tube is the backup. If the fill valve doesn't shut off, the extra water spills into this open tube and down to the bowl instead of onto your floor.

A running toilet means water is getting past one of two gates: the flapper at the bottom, or the fill valve at the top. The questions at the top work out which one.

Water on the floor around the toilet? See our guide to a toilet leaking at the base.

Who to call

Rather not do it yourself? Call a plumber.

That's a fine choice. Maybe you're busy. Maybe you're selling the house and just want it done right. A plumber can swap the worn part inside the tank, usually in one short visit.

$60–$150New flapper

$60–$200New fill valve

Most plumbers charge $45–$200 an hour, and some add a fee to come out.

Find plumbers near you

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What to say

Calling a pro? Here's what to say.

A few lines to read when they pick up, and the questions to ask before anyone comes out.

Before you call

Rent? Call your landlord first.

Home warranty? Call them first.

4.5 stars or more, and a license number.

Say this

Hi. My toilet keeps running. When's the soonest you can get here? And what's your fee for the visit? Does it go toward the repair?

Always ask

What's your fee to come out, and does it go toward the repair?
Do you charge by the job or by the hour?
Will you tell me the full price before you start any work?

Watch out if

They push a full replacement on the first visit for a small problem.
They won't give you a price before starting.
They add an emergency fee without telling you first.

Feeling pushed to decide on the spot? You can say no and hang up. You owe nothing for a phone call.

Know what's wrong before they come

Answer up to 5 quick questions. We'll give you the words a pro uses.

Answer the questions →

More of a list person?

Common symptoms, causes, tests and costs

Find the row that sounds like your toilet. The quick test is something you can check yourself in a few minutes.

What you notice	What it probably is	Quick test	Do it yourself	With a pro	Verdict
Runs after every flush; handle sticks or chain is tight	The chain or handle is holding the flapper open	Lift the lid and look at the chain and handle	Free	$50–$120	FIXSee the answer: The chain or handle is holding the flapper open
Water spills into the open tube in the middle of the tank	The water level is set too high	Lift the float by hand. Does the water stop?	Free	Not needed	FIXSee the answer: The water level is set too high
Hiss or trickle, or the tank refills on its own; dye shows up in the bowl	The rubber plug at the bottom of the tank is worn out	Food-coloring test: color in the bowl without a flush	$12–$30	$60–$150	FIXSee the answer: The rubber plug at the bottom of the tank is worn out
Water keeps coming even when you lift the float; steady hiss	The part that refills the tank won't shut off	Lift the float by hand. Does the water keep coming?	$12–$60	$60–$200	FIXSee the answer: The part that refills the tank won't shut off
Dye leaks to the bowl; flapper feels fine, but the ring is rough	The ring under the flapper is worn, or the overflow tube is cracked	Drain the tank and run a finger around the ring under the flapper	Pro job	$60–$250	CALLSee the answer: The ring under the flapper is worn, or the overflow tube is cracked

2026 U.S. averages, rounded. Pro prices include parts and labor. Most plumbers charge $45–$200 an hour, and some add a fee to come out. Nights, weekends and big cities cost more. See all repair prices

Want proof of where the water goes?

Three free tests that tell you

These show whether water is leaking out the bottom (the flapper) or coming in the top (the fill valve). No tools needed.

Food-coloring test. Lift the lid. Put about 10 drops of food coloring in the tank. Don't flush. Wait 15 minutes, then look in the bowl.
Listen test. Flush once, then leave the toilet alone for 30 minutes. Put your ear near the tank and listen for a hiss or trickle.
Pencil test. Turn the shutoff valve behind the toilet clockwise until it stops. Mark the water line inside the tank with a pencil. Come back in 30 minutes.

Color in the bowl, or the water dropped below your pencil mark: water is leaking past the flapper or the ring it sits on.
Bowl stays clear, but you hear a hiss: the fill valve probably isn't shutting off all the way.
Water spills into the overflow tube: the water level is set too high, or the fill valve is worn.
Clear bowl, no drop, no sound: no leak right now. Flush the colored water away so it doesn't stain, and turn the valve back on.

Not sure it's safe to leave it?

Turn off the water right away if…

Water is on the floor around the toilet or dripping from under the tank.
The bowl is rising toward the rim and not going down.
You see a crack in the tank or bowl, or water seeping from the porcelain.

To turn it off, find the small oval or round handle on the pipe behind the toilet, near the floor. Turn it clockwise until it stops. If it won't turn, don't force it. Turn off your home's main water and call a plumber.

A toilet that just keeps running is not an emergency. It wastes water, but it won't hurt anyone.

Got a big repair quote?

Should you repair it or replace it?

Almost every running toilet is fixed with cheap parts inside the tank. The bowl itself doesn't wear out.

Repair when the problem is the flapper, chain, float, fill valve or flush valve. These parts are made to be swapped.
Think about replacing when the tank or bowl is cracked, water seeps from the porcelain, or parts for a very old toilet are hard to find.
Check the quote. Two big cost guides put running-toilet repairs with a plumber at $50–$400. A quote far above that for a running toilet is worth a second opinion.

Example: a $120 flush valve repair on a solid toilet is worth doing. A cracked tank usually means a new toilet.

Ran into a word you don't know?

Toilet words, explained

Lift the tank lid and match these up. The drawings show roughly what each part looks like.

Tank: The box behind the seat that holds the water for the next flush. The lid is heavy porcelain, so set it on a towel.
Handle: The lever on the outside of the tank. Inside, its arm lifts the chain.
Chain: The small chain from the handle arm to the flapper. It needs about 1/2 inch of slack.
Flapper: The rubber plug at the bottom of the tank. It lifts to flush and drops to seal. It's the part that wears out most.
Flush valve: The hole at the bottom of the tank and the hard ring around it, called the seat. The flapper seals against it.
Seat: The hard ring under the flapper. If it gets rough or crusty, water leaks past even a new flapper.
Overflow tube: The open tube standing in the middle of the tank. Extra water spills into it and down to the bowl, not onto your floor.
Fill valve: The tall post on one side of the tank. It lets water in after a flush and shuts off when the float rises.
Float: A plastic cup or ball that rides up with the water and tells the fill valve when to stop. Its height sets the water level.
Refill tube: A small, bendy tube from the fill valve to the top of the overflow tube. It refills the bowl after a flush.
Shutoff valve: The small handle on the pipe behind the toilet, near the floor. Turn it clockwise to stop water going to the tank.
Supply line: The short hose from the shutoff valve up to the bottom of the tank.
Food-coloring test: A few drops of food coloring in the tank. If color reaches the bowl without a flush, water is leaking past the flapper.
Phantom flush: When the tank refills by itself with no one flushing. It usually means a slow leak past the flapper.

Still have questions?

Questions people ask most

Why does my toilet run every few minutes?

A toilet that runs every few minutes usually has a slow leak past the flapper. Water seeps into the bowl, the tank level drops, and the fill valve turns on to top it up. Pros call it a phantom flush. A new flapper is the usual fix.

Is a running toilet an emergency?

A running toilet is usually not an emergency: it wastes water, but it won't hurt anyone. It's urgent if water is on the floor or the bowl is about to overflow. Then turn the valve behind the toilet clockwise.

How do I stop a running toilet right now?

To stop a running toilet right now, lift the tank lid and jiggle the handle, or lift the chain and let the flapper drop. If it keeps running, turn the shutoff valve behind the toilet clockwise. Turn it back on when you need to flush.

Does a running toilet raise my water bill?

Yes, a running toilet raises your water bill. A toilet that runs all day can waste a lot of water, and you pay for all of it. Even a quiet leak you can't hear adds up. The food-coloring test will show it.

Which flapper do I buy?

Buy a flapper that matches the size of the hole at the bottom of the tank. Most are 2-inch or 3-inch. Look for a brand name inside the tank, or take the old flapper to the store.

Can I just jiggle the handle?

Jiggling the handle works for a moment if the chain is caught or the handle sticks. If you have to jiggle it every time, fix the chain or handle. It's usually a free 5-minute job.

Who do I call for a toilet that keeps running?

Most running toilets don't need a pro: a new flapper or a chain fix is a cheap job you can do. Call a plumber if the tank or bowl is cracked, or the shutoff valve won't turn. Call one too if it still runs after a new flapper and fill valve.

How much does it cost to fix a running toilet?

Fixing a running toilet often costs nothing if it's the chain or the float. A flapper or fill valve is a cheap part. With a plumber, cost guides put most running-toilet repairs at $50–$400.

How we built this

The questions follow the order a plumber checks a running toilet: the water level, the chain and handle, a dye test for the flapper, then the float, fill valve and flush valve seat. Each answer makes some causes more likely and others less likely.

Prices are 2026 national averages from published repair-cost guides, rounded. Your local prices will differ.

How we make money: some links go to parts stores that pay us a small commission, and some pro listings pay us when you call them. Verdicts come from the diagnosis, not from who pays more.