Adjustable Anti-Siphon Toilet Fill Valve: Install Guide
By Maintenance Depot Plumbing Team · Last reviewed
Quick answer
An adjustable anti-siphon fill valve refills your toilet tank after each flush. This universal valve adjusts from 8" to 13" to fit most tanks and its anti-siphon design meets plumbing codes.
A toilet that runs constantly, fills slowly or hisses usually has a worn fill valve. The adjustable anti-siphon fill valve is a universal replacement that fits most toilet tanks.
Specs at a glance
| Spec | Detail |
|---|---|
| Product | Toilet fill valve |
| Height adjustment | 8" to 13" |
| Design | Anti-siphon, code compliant |
| Fits | Most standard toilet tanks |
| Caution | Do not over-tighten the hex nut |
Features
- Anti-siphon design that complies with plumbing codes and protects your drinking water
- Twist height adjustment from 8" to 13" to suit most tanks
- Simple installation with common tools
Signs you need a new fill valve
- The tank keeps refilling or the water never stops running
- Water trickles into the overflow tube
- The tank fills very slowly
- Noisy hissing or whistling after a flush
How to install
- Turn off the water at the stop valve and flush to empty the tank.
- Sponge out the remaining water and disconnect the supply line.
- Unscrew the lock nut under the tank and lift out the old valve.
- Twist the new valve to the right height: the critical level mark should sit at least 1" above the overflow tube.
- Insert it, then tighten the lock nut by hand plus a quarter turn. Do not over-tighten the hex nut, as this can cause damage.
- Clip the refill tube to the overflow pipe, reconnect the supply, turn the water on and adjust the water level.
Tip
If water still runs after the fill valve is replaced, the flapper may be leaking. Maintenance Depot also stocks toilet flappers and flush handles.
Frequently asked questions
How do I know if the fill valve or the flapper is leaking?
If water runs into the overflow tube, it is usually the fill valve. If coloured dye in the tank leaks into the bowl, it is the flapper.
What height should the fill valve be set to?
The critical level mark should sit at least 1" above the overflow tube.
Why did my tank crack after installing a valve?
Over-tightening the lock nut can crack the tank. Hand-tight plus a quarter turn is usually enough.