How To Replace A Clogged Fill Valve In Your Toilet Tank

If you have older galvanized supply pipes, or your area has hard water (water that is contaminated by heavy metals and/or sediment and other materials), you may notice a brownish-red stain on your tub, shower, and other places that contaminants may collect.

This is especially evident in your toilet tank, where hard water or rust from old pipes may sit for long periods inside the tank before it is emptied. These particles can accumulate inside your fill valve and inhibit the ability of the float inside the valve to rise with the water inside the tank and signal for the valve to shut off when the tank is full.

The causes the fill valve to continue to run incessantly, with the extra water running into the overflow tube in your tank and your money flowing down the drain.

Fortunately, it's inexpensive and relatively simple to replace your clogged fill valve.

What will you need to replace the fill valve?

Fill valve

They fit most toilets universally, and cost under ten dollars at your local home improvement store.

Adjustable wrench

Teflon tape

This is a spool of thin plastic ribbon use to seal pipe threads and costs less than a dollar.

Rags or sponge for absorbing water 

Removing the clogged fill valve

You will begin by shutting off the valve to the toilet's supply line. This valve is located under the left side of the toilet (facing the toilet). Turn it in a clockwise direction until you can turn it no more.

You will then flush the toilet a few times until as much water is drained from the tank as possible, then use rags or a sponge to absorb any remaining water. 

Next, you will use the adjustable wrench to disconnect the supply line from the bottom of the fill valve under your toilet tank..Turn the connecting nut in a counterclockwise direction until it is separated from the threaded male connection on the bottom of the fill valve. Hold the supply line upright until you dump pour any remaining water inside the line into a cup or pail.

You will then remove the plastic nut that holds the fill valve in place under the toilet tank. It should be only hand tightened, so no wrench should be required. You can then lift the fill valve from the tank.

Installing the new fill valve

You will begin by wrapping a few layers of teflon tape in a clockwise direction around the threads of the male connection at the bottom of the fill valve, then insert the valve into the opening in the bottom of the tank, resting it securely inside the round indentation around the opening.

You will then secure it to the tank by hand tightening the large plastic nut to the bottom of the tank, then connecting the supply line to the threaded connection at the bottom of the valve.Tighten the supply line connection with the adjustable wrench.

After all connections are made, twist the top portion of the fill valve in a counterclockwise direction to adjust it's height. The top of the valve should be set at a height that is one inch below the top of the overflow tube, a narrow length of plastic tubing that rests vertically in the center of the tank.

When the adjustment is completed, you can turn on the supply valve and let the tank fill. The valve should shut off at the fill level marking on the inside of the tank, or one inch below the top of the overflow tube opening.

If you need to adjust the water level, turn the top of the fill valve counterclockwise to raise the level and clockwise to lower it. When the task is complete, you can rest with the satisfaction of knowing that your test ten dollar investment and sweat equity will pay big dividends in future water bills. For more information, visit websites like