If there isn’t a water line indicator on the valve and your toilet ran well in the past, check the walls on the inside of the tank for calcium buildup and water stains. These signal where the water normally sits and you can easily compare it to the water level. If you want to mark a fill line on the valve, mark the location where the water should be with electrical tape after drying the spot with a clean towel.

Ballcock fill valves have a rubber ball on a rod that floats on top of the water. When water fills the tank, the ball raises until it shuts the water off by sliding a cover over the valve. Float-cup fill valves have a cylindrical cup that slides up and down on a pipe. The cup floats on the surface and shuts the valve when the tank is full. Internal fill valves have a large plastic top and a cylindrical bottom. The float is inside the vertical cylinder and runs more quietly than other valves.

You don’t need to turn the water off if there’s a screw on top of the fill valve connecting to the float. While the water in the toilet bowl isn’t sanitary, the water inside of your tank is fine. Don’t feel yucky or grossed out getting your hands wet in the tank!

Position the bottom of the ballcock so it’s level with the fill line.

This works best if the ballcock uses a metal rod. Plastic rods may break or snap instead of bending.

It may take a couple of tries to get the ballcock adjusted to the correct level.

The screw on top of the fill valve might be labeled “tank water” or “tank level” so it’s easy to locate.

Typically, turning the screw about 8 times will raise or lower the water level by 1⁄2 inch (1. 3 cm).

If you have a ball float, disconnect the chain attaching it to the fill valve or unscrew it completely before trying to remove the fill valve cap.

The washer in your fill valve helps seal off the water when your toilet isn’t running. Every fill valve is different, but the washer is almost always a different color than the rest of the mechanism.

If the rubber washer is damaged, replace it with one made by the same manufacturer as the valve since the pieces aren’t universal.

Keep the cup over the valve so the water doesn’t spray outside of the tank.

Remove any debris that comes out of your fill valve before refilling the tank.

If your fill valve is still acting up or making noise, you may need to replace it.