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How To Fix A Running Toilet
A running toilet is one of, if not the most, common problems that any household can have. The constant stream of leaking water is not only plainly annoying, but it can also rack up your water bill unexpectedly with all of that wasted water down the drain.
The good news is that for most running toilets, the solution comes down to a handful of easily identifiable causes, many of which can be fixed in less than an hour with common tools and a part that won't hurt our pockets.
In this guide, we'll walk you through all the exact steps needed to fix a running toilet, highlighting the common causes, what to find inside your tank, and how to know when it's time to call your plumber for a fix. If you are also thinking about upgrading your toilet setup at the same time, our bidet toilet seats and complete bidet toilets are worth exploring once your repair is done.
Why Is My Toilet Running?
It helps to know what causes your toilet to keep running before you try to fix anything. In most cases, something inside the tank itself is wither worn out or not in position, causing water to leak constantly from the tank towards the bowl.
The top three common causes are:
- A faulty or worn flapper that is not sealing properly against the drain hole
- A float set too high, causing water to overflow continuously into the overflow tube
- A fill valve that will not shut off after the tank refills
Identifying which part is not working properly will tell you exactly what to fix, saving you time and money on replacing and fixing parts you do not need.
What You Will Need
Gather these few basic items first before you open the tank:
- Wrench or pliers (adjustable)
- Flathead and Phillips screwdrivers
- Replacement flapper
- Replacement fill valve (if needed)
- Towels or a small bucket
- White vinegar (For mineral buildup if present)
How To Fix A Running Toilet: Step By Step
Step 1: Identify the Problem by Opening the Tank
Lift the cover of the tank and set aside on a flat surface. Afterwards, look inside the tank, observe the water flow to see what's happening.
Things to ask yourself:
- Is water leaking into the overflow tube - the tall tube in the center of the tank?
- Is the flapper laying ground flat and sealed properly against the drain hole at the bottom of the tank?
- Is the fill valve still accumulating water even when the tank looks full?
Step 2: Check and Adjust the Flapper
The flapper, a seal made of rubber at the bottom of the tank, opens when you flush your toilet and closes after to keep the water that is refilled by the fill valve. As you use your toilet more and more, the flappers usually either crack, loosen up or collect built-up minerals from the water which prevents itself from sealing the drain hole fully.
To test your flapper:
To test your toilet's flapper, you can first try by pressing it down while you run the toilet. If the sound keeps going, your flapper is working properly. If it suddenly stops, that usually means that the flapper is not fully sealed and needs to be worked on based on the identified problem.
To replace a flapper:
- Turn off the water supply behind the toilet (Twist the valve clockwise)
- Then flush to empty most of the tank
- Once the water is drained, unhook the flapper from the two side pegs on the overflow tube.
- Take off the chain from the flush handle.
- Buy a new flapper, bring the old one with you to the store so you can buy the correct size or buy a universal model that works with most toilets.
- Install the new flapper by snapping it onto the pegs and reconnecting the chain. Make sure there’s a little margin of slack in the chain that will allow the flapper to open fully when flushing without having any issues of closing completely.
- Turn on the water supply.
- Let the tank fill.
- Do a test flush.
Replacing the flapper is one of the easiest fixes with running toilets and it only costs around $5 to $15.
Step 3: Adjust or Replace the Float
The float controls the amount of water filled in the tank. For example, if it's set too high, water will just leak into the overflow tube and your toilet will continuously run. Set too low and you'll barely have enough water to flush your toilet.
The level of water should sit around one inch below the overflow tube's top. If the water's too high, you must lower the float to adjust accordingly.
There are two common float types:
Ball float (older style): The round ball on a metal arm. You can either try turning the small screw near the fill valve or bending the arm down slowly so the ball sits lower in the water.
Cup float (modern style): This is the float that slides up and down the fill valve. Try pinching the clip on the side and slide it down to lower the water level.
Once you're done adjusting, flush and check the refill. The water should stop at about one inch before the top of the overflow tube.
Step 4: Check and Replace the Fill Valve
If the running toilet still goes on even with the correct water level, the problem may lie with the fill valve as it can commonly wear out and stop working properly over time.
Though fill valves often last a couple of years, they eventually do need to be replaced once issues arise.
To replace a fill valve:
- Turn the water supply off through the valve
- Flush to empty the water in the tank
- Use a towel or sponge to absorb any water left in the tank
- Remove the water supply line from the bottom of the tank.
- Unscrew the locknut beneath the tank that holds the fill valve intact. Turn it counterclockwise with your hand or with pliers.
- Pull the fill valve straight up and out from tank.
- Insert a new fill valve, adjust its height according to the package instructions so it sits around an inch below the top of the overflow tube.
- Tighten the locknut beneath, turn the supply line on, and attach the small refill tube from the fill valve to the top of the overflow tube.
- Turn the water on slowly, check for leaks at the base of the new valve and at the supply line connection.
Fill valves are just about available in any hardware store and will only cost you about $10 to $20. Most of these valves are designed to fit universally with a lot of standard toilet models.
How To Fix A Running Toilet With A Button Flush
Toilets with a button flush (also called dual flush toilets) work completely different from the traditional lever-flush models. They tend to be common nowadays in newer homes and in modern toilet designs, including many Toto dual flush toilets.
If your button flush toilet keeps leaking non-stop, one of these may be the reason as to why:
- A worn seal inside the tank.
- Buttons that get stuck or don't fully come back up.
- A seal in the tank that is either out of place or is damaged.
To fix a running button flush toilet:
- Turn off the water supply.
- Flush to empty the tank.
- Remove the flush button. In most models, you can press it down and turn it counterclockwise, or you can unscrew a cap that may be in the center.
- Lift out the flush valve tower from the tank.
- Check the rubber seal at the base.
- If the seal looks uneven, it won’t seal properly and should often be replaced. If the whole part looks worn out, replacing it entirely always solves the issue.
- If the button is somehow sticking, clean around the button housing and make sure, after pressing it, that it springs back freely on its own.
- Reassemble then turn the water supply back on.
- Test both flush buttons.
Before you buy any parts, check out the brand and model of your toilet. Button flush systems may vary so getting the right match the first time around is usually the best outcome.
How To Fix A Running Toilet Tank
If by some chance that water is leaking onto the outside of the tank and not going into the bowl, it could be the the bolts that hold the tank in place or what we call the tank-to-bowl gasket.
To inspect and fix a leaking tank:
- Dry the outside of the tank with a towel and wait a few minutes to see where the moisture comes from.
- If the bolts are slightly loose and damp, tighten them using a screwdriver or a wrench.
- Hold the nut under the tank while tightening it from the top. Be careful with tightening the nut excessively as the pressure can definitely crack the porcelain of your toilet, especially if it's too much.
- If water is coming from the thick rubber gasket between the tank and bowl, the gasket is most likely worn out and has to be replaced. This means you’ll need to remove the tank.
- To do this, turn the water supply off, flush the toilet, disconnect the water line and lastly, unscrew the tank bolts that are in place.
- Lift the tank off your toilet then replace the gasket and the washers before putting everything back in place.
If you notice a crack in the porcelain tank, this can no longer be fixed and the tank has to be either be replaced or checked by a plumber.
How To Fix A Running Toilet Without A Ball Float
A lot of newer toilets don't go for the old-style ball float anymore. They instead use a cup float or column float that's directly attached to the fill valve itself. If by chance that your toilet still keeps on running, it's nothing more than just an easy fix.
- Open the tank and find the fill valve (around the left side).
- Look for an adjustment clip, ring, or screw on the body of the valve.
- Either turn the screw counterclockwise or pinch the clip and slide it downward to lower the water shutoff point.
- The water level should be around an inch below the top of the overflow tube once the tank refills.
- Flush the toilet then let it refill again to see if the water stops at just the right level.
If adjusting the cup float does not solve the running water even after multiple attempts, the fill valve is most likely worn out and should be replaced following the steps in Step 4 above.
How To Fix A Running Toilet Without A Flapper
A bunch of newer toilets (like some Toto smart toilets) don’t use the rubber flapper anymore. They instead use a part called a tower or canister which is tall and usually made of plastic. It can still have some leaking issues but is nothing more than an easy fix.
To fix a running toilet with a tower flush valve:
- Turn off the water supply
- Flush the toilet tank empty.
- Open tank and look inside. If you see a tall tube instead of a rubber flap, that’s your tower flush system.
- Twist the upper part of the tower and lift it up.
- Look at the rubber seal at the bottom. If it’s hard, cracked, or worn out, that means that it must be replaced.
- You can buy a replacement seal at any hardware store, just make sure that it matches the brand of your toilet.
- Put the tower back in, twisting to lock it in place.
- Turn on the water supply.
- Do a test flush and check if it still runs.
9 times out of 10, a cheap seal that costs around $5 to $15 is all that you need to fix it.
How Much Does It Cost To Fix A Running Toilet?
This depends on what part is broken and if you fix it yourself or hire a plumber to do it for you.
DIY repair costs:
- Flapper replacement: $5 – $15
- Fill valve replacement: $10 – $20
- Float adjustment: No cost
- Tank-to-bowl gasket and bolt kit: $10 – $25
- Tower flush valve seal kit: $5 – $15
- Full tank rebuild kit (flapper, fill valve, and handle): $20 – $50
Plumber costs:
- Diagnosis and simple repair: $75 – $150
- Full internal tank rebuild: $150 – $300
- Toilet replacement if beyond repair: $300 – $600 or more depending on the model
A simple issue usually can usually be repaired by yourself and wouldn't cost you more than $25 nor would it take more than an hour. But if your toilet keeps breaking again and again because it’s old, it might be better to upgrade instead. A new complete bidet toilet or bidet toilet combo can save you from constant repairs and give you a more modern and cleaner setup.
When To Call A Plumber
Most running toilets can be repaired by yourself, but sometimes it’s better to call the professionals.
You should get help if:
- The tank or bowl has any sort of crack
- The water keeps running despite replacing the flapper and the fill valve.
- Water is leaking onto the floor.
- You have a smart toilet and don’t feel comfortable tampering with the internal electronics.
- Your toilet is 15–20+ years old and keeps breaking again and again.
If your toilet keeps having problems and you’re thinking of replacing it, it might be a good time to look at your options. Our guide to what is a smart toilet is a good starting point for understanding your options. You might also want to read about how to install a bidet if you are adding a bidet seat to a newly repaired or new toilet.
Thinking About Upgrading While You Are At It?
If your toilet is already older and you’re doing a repair anyway, it might be a good time to think about upgrading.
A bidet toilet seat is the easiest option. It fits most regular toilets and can usually be installed in under an hour. It adds features like a warm seat, water cleaning, and air drying without replacing your whole toilet.
If you want something more advanced, a smart bidet or complete bidet toilet replaces the entire toilet. It’s an all-in-one setup made for better comfort and hygiene.
If you are new to bidets and want to understand the basics first, our guides on what is a bidet and how do bidets work are a good place to start.
Frequently Asked Questions
How to fix a toilet that keeps running?
To fix a toilet that keeps running, open the tank and check the main parts inside. It’s usually a bad flapper, a float set too high, or a fill valve that won’t stop. Press the flapper to test it, check if water is going into the overflow tube, and see if the fill valve keeps running. Replace or adjust the part causing the problem.
How to fix a running toilet with a button flush?
To fix a running toilet with a button flush, turn off the water and remove the button. Take out the flush valve tower and check the rubber seal at the bottom. If it looks worn, replace it. Put everything back and test the buttons.
How to fix a running toilet tank?
To fix a running toilet tank, first check if the water is inside or outside the tank. If it’s inside, check the flapper, float, and fill valve. If it’s outside, check the bolts and the gasket. Tighten or replace parts as needed.
How to fix a running toilet without a ball float?
To fix a running toilet without a ball float, find the cup float on the fill valve and lower it. Use the clip or screw to adjust it until the water level sits below the overflow tube. If it still runs, replace the fill valve.
How much does it cost to fix a running toilet?
To fix a running toilet, it usually costs between $5 and $50 if you do it yourself. A flapper is the cheapest fix. If you hire a plumber, it can cost around $75 to $300.
How to fix a running toilet without a flapper?
To fix a running toilet without a flapper, remove the tower or canister inside the tank. Check the seal at the bottom and replace it if it’s worn. Put it back and test the flush.
Summary
Fixing a running toilet is usually pretty simple. Just open the tank and check if the flapper, float, or fill valve is causing the issue. Once you find the problem part, adjust it or replace it, and the toilet should stop running within an hour. Most of the time, you’ll only need basic tools and a cheap replacement part from a hardware store—usually under $20.
If your toilet keeps acting up or is getting old, it might be easier to upgrade instead. Browse our full selection of bidet toilet seats, and bidet toilet combos to find the right fit for your bathroom.