How To Change A Clogged Fill Valve In Your Toilet Tank

If you have older galvanized pipes, they are likely to be filled with accumulated rust and corrosion. The easiest way to check for this issue is in your toilet tank. Water sits for an extended period in your tank, and these materials will form a brown film that will coat the inside of the tank.

While this discoloration is not pleasant, it's also not visible without removing the tank lid. However, the rust and corrosion will also accumulate inside the tower fill valve in the tank. This will stop the float from rising inside the fill valve, allowing the water to continue to run without stopping as it spills over the edge of the overflow tube.

Fortunately, it's easy to install both a new fill valve and a filter that will clean the water before it enters the tank.

What you will need for the task

  • Tower fill valve
  • Water filter with male and female connections for installing between supply valve and supply hose of toilet
  • Adjustable wrench
  • Teflon tape
  • rags or paper towels

Tower fill valves are fitted universally for most toilet tanks, and water filters for a toilet line should have 3/8" diameter connections for most toilets.

Removing the Old Fill Valve

You must first turn off the supply valve to the toilet, then flush the toilet repeatedly to remove as much water as possible from the tank.  You can then absorb the remaining water with rags or a sponge until the tank is dry. Use the adjustable wrench to disconnect the supply hose from the bottom of the fill valve, which extends from the bottom of the tank, then loosen the hand-tightened plastic nut that holds the fill valve in place inside the tank. You can then lift the valve from the tank. Clean any stains from the tank as desired.

Installing the new fill valve

Wrap teflon tape in a clockwise direction around the threaded connection at the bottom of the fill valve, then wrap teflon tape around the threads of the male connection of the water filter. Insert the bottom of the fill valve through the bottom opening in the tank, then secure it by hand-tightening the plastic nut that holds it in place.

You will then twist the female connection of the water filter around the threaded male connection of the fill valve. Twist it fully until it is snug, then connect the end of the supply line to the threaded male connection of the water filter. Use the adjustable wrench to tighten it securely.

Adjust the height of the fill valve by twisting the top portion counter-clockwise until the top of the fill valve is about one inch below the top of the overflow tube in the center of the tank. Turn on the supply valve and watch the tank fill. Adjust the top of the fill valve as needed until the water level is one inch below the overflow tube opening.

Your tank will now be filled with clean water that will not stain or clog your fill valve.

For additional advice, contact a plumber at a company like O'Brien Plumbing.