How To Install a Ballcock Fill Valve

Learn how to replace the ballcock fill valve in your toilet

1-2 hours
Install a Ballcock Fill Valve

Many older toilets have ballcock fill valves that will eventually need replacing due to use and wear. If your toilet runs constantly, makes odd humming or groaning sounds or the handle feels light when you press down on it and the toilet won’t flush, you may need to replace your toilet’s ballcock assembly valve.

This guide will give you step-by-step instructions on how to replace a toilet ballcock fill valve.

What You'll Need


Shut off the water and flush toilet to empty the tank
Shut water flush toilet - Install Ballcock Fill Valve

From underneath the tank, place a bucket under the retaining nut. Now remove the ballcock retaining nut with an adjustable wrench and take out the old ballcock assembly.

Place and align new ballcock valve
Place align new valve - Install Ballcock Fill Valve

• Attach a new cone washer to the new ballcock tailpiece and insert the tailpiece into the tank opening
• Align the float arm socket in float arm will pass behind the overflow pipe.
• Screw the float ball onto the float arm.

Attach refill tube
Attach refill tube - Install Ballcock Fill Valve

Bend or clip the refill tube so that the tip is inside the overflow pipe.

Attach supply line
Attach supply line  - Install Ballcock Fill Valve

• Screw the mounting nut and the supply-line coupling nut onto the ballcock tailpiece and tighten it with an adjustable wrench. (Note: over-tightening the nut can crack the toilet tank.)
• Turn on the water and check for leaks.

Adjust the water level in the tank
Adjust water level tank - Install Ballcock Fill Valve

The water level in the tank should be about ½-inch below the top of the overflow pipe, or align with the marked "full" line inside the tank.