Whether you're installing a new Gerber toilet, setting the water level right the first time around can keep your toilet tank from constantly running. If your water level is set too high, toilet water can overflow into the pipe instead of stopping at the water level mark, causing the toilet to constantly run. A low level which is too low can cause the toilet not to flush properly or remove everything from the toilet bowl.
Remove the tank cover from the back of your Gerber toilet.
Locate the water level adjustment screw. The water level adjustment screw is typically found on top of the fill valve or at the bottom of the tank. In Gerber toilets, the water level adjustment screw is usually located next to the flow rate adjustment screw.
Use a pair of pliers to turn the screw and adjust the level of the water. When adjusted correctly, the top of the water should reach the water level mark on the side of the tank when the tank is full.
Remove the cover from the back of your Gerber toilet tank.
Rotate the adjustment rod on the fill valve 90 degrees. Remove it from the inner float.
Lower the outer cup to lower the water level. Raise the outer cup to increase the water level. The water level should reach the water level line on the inside of the tank when the water level is adjusted correctly.
Secure the inner float into the lowest possible position, once you've adjusted the outer cup and the water level. Slide the adjustment rod back into place.
Rotate the adjustment rod until the flat side is facing toward the wall of the tank, and it cannot be easily removed.
When adjusting the water level on a tank with a cup, a 1/4-inch increase or decrease in the water level typically coincides with a single notch on the fill valve tube.