How to Identify Different Types of Toilet Fill Valves

When your toilet tank stops filling up you have a fill valve problem that will need adjustment or replacement. Fill valves or "ballcocks" are the major component inside your toilet tank and being able to identify what type of fill valve you have is essential when selecting a replacement.

Some types are older technologies and should be updated when a replacement is purchased and others work quite well and just need to be replaced.

Worth noting is that anti-siphoning capabilities are...MORE required on fill valves by plumbing code. Think of an anti-siphoning device as a one-way valve. Anti-siphon devices protect against a period of low water pressure in the supply line where contaminated water could be sucked back into the potable water supply. Modern US plumbing codes require the ballcock to have an anti-siphon device as an integral part of the fill valve itself. The anti-siphon device can be a vacuum breaker or an air gap and is located on the side of the ballcock where water leaves the fill valve and flows through the refill hose and into the overflow pipe.

Let's take a look at the four most common fill valves you may find in your home:

  1. Plunger / Piston Type Fill Valve
  2. Diaphragm Type Fill Valve (brass body)
  3. Diaphragm Type Fill Valve (plastic body)
  4. Float Cup Type Fill Valve
  5. Float-less Type Fill Valve
  • 01 of 05
    plunger toilet fill valve
    The Mansfield Style 09 plunder ballcock from Prier Products is a great example of the plunger / piston design fill valve. © Prier Products 2012

    Plunger / Piston Fill Valve Construction:

    Plunger or piston style fill valves or "ballcocks" are among the earliest style of toilet tank fill valve designs. They are made of a heavy duty cast brass body typically providing quiet operation. This style of ballcock uses a characteristic bottom-fill water discharge tube and is designed with a hinged lever assembly above the ballcock which often use thumbscrews at some hinged joints to allow adjustment of lever arm movement.

    The de facto standard in early plunger style fill valve was the Mansfield 09 with many still in service today. In 2007, Mansfield’s brass division was purchased by Prier, an excellent quality brass plumbing and industrial products manufacturer. The Mansfield 09 is still manufactured by Prier but the ballcock is not listed as anti-siphon by the manufacturer. Wolverine Brass makes a similarly styled anti-siphon ballcock called the Wolverine Model 50568 (10”) or the Model 50569 (12”) They also make an adjustable height anti-siphon plunger ballcock, Model 56568. Cesco Brass also makes a similar style anti-siphon plunger ballcock called the Burlington 20A.

    If you have one of these old style fill valves they should be replaced because they do not meet current plumbing codes as they are not anti-siphon.

  • 02 of 05
    brass ballcock
    Older style cast brass body diaphragm ballcocks are reliable and long lasting. © 2012

    Diaphragm Fill Valve Construction:

    Like the plunger or piston fill valve, diaphragm ballcocks have been around a long time but have some important differences.

    One such difference is that they are anti-siphon. They can come in a cast brass body or plastic body construction.

    Cast brass construction is found on older models such as the Mansfield 07 or the Wolverine Model 58577, both of which are anti-siphon. On an older style diaphragm ballcock the bonnet or cap is made of cast brass just like the rest of the fill valve body. The button that actuates the diaphragm is plastic.

  • 03 of 05
    plastic body diaphragm ballcock
    Contemporary plastic diaphragm ballcocks adjust the water level by use of an adjusting screw on the top of the fill valve. © 2012

    Diaphragm Fill Valve Construction:

    Plastic body construction is what you find on most newer model anti-siphon diaphragm ballcocks and is the most common construction found in a diaphragm fill valve replacement.

  • 04 of 05
    float type ballcock
    The Fuidmaster 400a floating cup ballcok is a popular workhorse of a fill valve. © Fluidmaster, Inc. 2012

    Float Cup Fill Valve Construction:
    The float cup fill valve is made of plastic and is a more “modern” style anti-siphon fill valve originally introduced in the late 1950’s by Fluidmaster®.

    This type is identified by a plastic floating O-shaped cup that moves up and down around the fill valve shaft. The floating cup is attached using  a metal spring clipped to a metal actuating rod.

    Continue to 5 of 5 below.
  • 05 of 05
    floatless ballcock
    The Keeney K830-14 floatless fill valve works without a float road and ball. © Keeney Manufacturing Company 2012

    Floatless Type Fill Valve Construction:
    The floatless ballcock is made of plastic and is a newer innovation in anti-siphon fill valves. These fill valves use a diaphragm pressure sensing mechanism as opposed to any type of float mechanism to adjust water level in the toilet tank. Originally designed for low profile / low flow toilet tanks of the 1990’s, these fill valves are usually inexpensive but the design has been known to have a spotty record of reliability.

    You will find these valves attached to the bottom of the tank as they operates under water.