Ballcock or Fill Valve

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The ballcock is one of the two major components necessary for a toilet tank to function, i.e., the ballcock (fills the tank with water) and the flush valve (releases the stored water into the toilet for flushing).

The ballcock goes by a few other names such as the fill valve or the refill valve, but its function is the same, to fill the toilet tank with water.

The ballcock comes in four basic variations:

  • Plunger / Piston Type Ballcock
    This style fill valve is the has been around the longest and is the oldest style ballcock available. It is typically made from brass metal and works on a simple lever principle where a float ball and rod depresses or raises a plunger in the valve to stop or start the filling of the toilet tank. You will find this ballcock almost exclusively in brass and is available in antique period reproductions.
  • Diaphragm Type Ballcock
    The diaphragm fill valve is available in brass and plastic versions. It operates similarly to the plunger fill valve in that the float ball and rod depresses or raises a button that moves a rubber diaphragm in the ballcock's bonnet or cap. This allows the water to start or stop flowing.
  • Float Cup Type Ballcock
    Float cup fill valves are a newer style ballcock introduced in the 1950's and are made from plastic. The float cup moves along the fill valve shank and it's height is determined by the placement of a spring clip affixed to a pull rod which turns the valve on and off. This type of ballcock is sometimes referred to as a variation of the Floatless Ballcock in that it eliminates the traditional float ball and rod, but it still uses a float and lever rod.
  • Floatless Type Ballcock
    Floatless ballcocks are also made from plastic eliminate the need for a float and rod. The floatless ballcock uses a pressure sensing device and sits at the bottom of the tank.

US plumbing codes require anti-siphoning capabilities on all new ballcock/fill valves.

Also Known As: fill valve, refill valve