The three most common causes of a toilet that keeps running are a faulty overflow tube, flush valve, or fill valve. Replacing any of these parts will usually stop the toilet from constantly running. Will a running toilet eventually stop? A running toilet will rarely stop on its own.
It sounds like the fill valve is sticking open. Turn off the water, remove the plastic cap on top of the fill valve, hold a glass or cup over it, and turn the water on for 5 to 10 seconds. Turn the water off, and replace the plastic cap, then try it again. If that didn't work, get a new fill valve and replace it.
Unless the water supply is turned off, the tank will fill when the fill valve opens. If the flapper is worn or improperly seated, water will continually run from the tank into the bowl, which will trigger the fill valve. Check the flapper first.
Take a crescent wrench to the ``bonnet'' of the new shut off, the little nut behind the handle, loosen that then loosen the handle, the guts of the shut off will come Out. Toss the metal body you won't need it. Repeat this process on your shutoff valve behind the toilet. Then tighten it back down, close the handle.
There may be a hidden plumbing leak in the walls of your home, or maybe your toilet is running when it's not in use. These “hidden” leaks can cause your home to be using water even when your main water valve is turned off.
Use of the Day: Keep valve stems and faucets rust-free by spraying them with WD-40.
A toilet that cuts on and off by itself, or runs intermittently, has a problem that plumbers call a "phantom flush." The cause is a very slow leak from the tank into the bowl. This problem is almost certainly caused by a bad flapper or flapper seat.
A continuously running toilet can waste up to 200 gallons a day or more depending on the volume flow down the drain. This can cause a terrible increase to a family's typical water use, so fix toilet leaks as soon as possible. Some leaks are easy to find, such as a dripping faucet or running toilet.
In older toilets, you'll need to adjust the float cup by bending the metal rod or float arm attached to it. In modern or newer toilets, push the floater clip, or turn the screw of the flush rod. Keep adjusting the rod until the water supply stops running when the tank empties and then refills from the fill valve.
The flapper, also known as the flapper valve, is a rubber component that seals the flush valve opening, retaining water in the tank. If the rubber flapper is worn, dirty, or warped, it may not close properly, allowing water to leak into the toilet bowl.
Valve Replacements: Valve replacements cost $50–$150 and resolve noisy or slow toilets. The fill valve refills the tank after each flush, the shut-off valve controls water flow, and the flush valve controls water coming from the tank to the bowl.
The Short Answer Is: A leaking toilet shut-off valve can be caused by a worn-out or faulty valve, loose connections, or a damaged water supply line.
Fixing a toilet fill valve (once referred to as a ballcock) is relatively easy to repair if you have a standard Fluidmaster brand valve. Often, a fill valve is repaired by simply replacing the entire fill valve, but Fluidmaster fill valves can be corrected by just replacing a seal inside the unit.
Generally, it's a good idea to consider replacing the toilet fill valve every 4 to 5 years.
If the flapper is worn or the seat that the flapper rests on is damaged, the water level will stop just below the flapper. If the gasket that seals the flush valve into the tank is deteriorated and leaking, the water would most likely drain completely out of the tank.
Lift up on the fill valve arm. If the water stops, the fill valve needs to be adjusted. To adjust the fill valve, turn the screw in the indicated direction until the water is about 1/4” below the top of the fill tube. You'll need to “reboot” the toilet by flushing it between adjustments to see if it's right.
Ghost flushing, or phantom flushing, occurs when your toilet tank refills independently without anyone pressing the handle. Water leaks from the tank into the bowl, causing the fill valve to activate periodically to refill the tank. It's similar to your toilet flushing itself, but it's just refilling.
Use a Spray Lubricant: You can use WD-40, which won't damage the rubber washer. Spray it onto the valve and leave it for 10 minutes. You should then be able to turn the valve.