Is your toilet making a loud hissing noise or sounding like it is refilling every few minutes? A constantly running toilet can be frustrating, especially when the sound keeps you awake at night or leaves you worried about a higher-than-normal water bill.
The good news is that this is a common plumbing problem, and in many cases, the cause is relatively simple to identify. Components inside the tank can wear out over time, allowing water to continuously leak from the tank and trigger the refill cycle over and over again.
In this guide, we will explain the most common reasons a toilet keeps running, what causes those annoying hissing and refilling sounds, and the steps you can take to diagnose and fix the problem.
As a temporary solution, the water should stop running when you shut off the toilet’s angle stop valve. If you cannot make the repair immediately, you can leave the valve closed and open it only when you need to flush the toilet. This can help prevent water waste and keep your utility bill from climbing while you arrange a permanent fix.
An old and rigid flapper
The first thing is to check if the toilet is leaking. If, as we suspect, the problem is due to a malfunctioning flapper, you will see ripples across the face of the water inside the toilet bowl. This is because of the water leaking from the tank into the bowl.
Next, reach into the tank and push down on the flapper. The flapper is the rubber seal that sits directly on top of the valve opening at the bottom of the tank. Its job is to seal the valve and prevent water from running into the bowl when the toilet is not flushing.
To fit snugly over the valve opening and seal it, the flapper should be soft. An old flapper that has become rigid will not create a tight seal. This may be why water is leaking into the toilet bowl, causing the toilet tank to constantly refill.
To check if this is the problem, press down on the flapper to see if water stops leaking into your toilet bowl. If it does, it means you have a malfunctioning flapper. Replacing the flapper will solve your problems. When purchasing a new flapper, it is a good idea to take your old one along to ensure you buy one that matches your toilet.
Cracked flush valve
Sometimes, the flapper is not the problem. Even if the flapper is in good condition and creating a tight seal above the flush valve, your toilet will run if the flush valve itself is damaged. If the edge of the flush valve is chipped, you will have a nonstop flow of water into the tank.
Replacing a flush valve is easy; however, it is a fairly involved process that requires you to take down the toilet tank. You may want to have a professional plumber undertake this part of the problem. A good plumber should be able to replace your flush valve within an hour.
Broken ball valve
In older toilets, the tank has a ballcock or ball float valve. As the name implies, this is a prominent ball found inside the toilet tank. The ball valve controls the mechanism that allows the tank to fill after it has been emptied during flushing.
When the tank is empty, the ball drops to the bottom of the tank, opening the water inlet valve to let water flow into the tank. As water fills the tank, the ball rises slowly with the water level, gradually closing the valve until it is completely shut. This stops the flow of water.
However, if the ball valve is broken, it will not work. Instead of rising with the water level inside the tank, it will remain underwater. Because the water inlet valve is not closed, water will flow into the tank nonstop. This excess water will escape from the tank via the overflow pipe.
The sound of water flowing into the overflow pipe is what causes the strange noise you hear from your toilet. To fix this problem, simply replace the ball valve.
Faulty fill valve
Modern toilets have a fill valve assembly in place of a ballcock valve. Just like a ball valve, the fill valve can malfunction, causing unchecked water flow into the toilet tank. This problem is often due to a worn seal or debris inside the fill valve assembly.
To fix this, disconnect the screw that holds the fill valve to the float valve. Open the fill valve by gently lifting the top and turning it counterclockwise. Check inside the fill valve cap for a diaphragm valve. If there is debris inside it, wash it thoroughly with soap and then rinse it.
If there is debris inside the fill valve, open the angle stop to flush out the dirt with water. If this solution doesn’t work, the only option is to replace the entire fill valve assembly. If this is what you should do, please contact a local plumber.
