When I flush my toilet, the water level will drop about an inch after the tank fills and then fill up again. This goes on non-stop UNTIL I turn the supply off. If I turn the supply off immediately after the tank fills, then the water level does NOT drop. I have replaced the flapper, adjusted the flapper, and disassembled the fill valve in the tank to check for calcium deposits. I have cleaned the seal under the flapper. I have put petroleum jelly on the flapper. It does not make sense that the leak does not happen if I turn the supply off immediately after the tank fills. Any ideas as to what is going on and how to fix it?
Toilet only leaks when supply is on
toilet
Related Solutions
That's a fairly popular fill valve. To open it:
- Shutoff the water, you don't want a geyser.
- Lift the float to the top position.
- While holding up the float, push down on the top cap and twist the cap a quarter turn (I believe counter clockwise).
The cap will then lift off and you can inspect and clean any parts. Before reinstalling the cap, move any small parts to a safe location, get a small cup to place over the top of the valve, and turn on the water supply. This will jet water straight up from the top of the valve and clear out any debris.
Reinstalling the cap is the reverse of the above procedure. Put the parts back, position the cap back on top, lift the float, press down on the cap, and twist.
Note that if cleaning it doesn't work, it's fairly simple to replace this fill valve.
I've run into this same problem several times, and tried the same things you're trying - adjust the ball, bend the arm a bit to put more pressure on the valve, etc.
Ultimately though I've always ended up replacing the fill valve. The pressure from the float ball and arm isn't enough to close the valve completely, a seal is worn out, or something else is similarly out of whack.
ETA: In my experience, the fill valves that don't have a ball but instead have a sort of integrated float seem to be less prone to this problem (like the one pictured below)
Related Topic
- Toilet Tank slow leak, have all new parts, tried all troubleshooting…help!
- Water – Toilet fill value hissing and dripping after it reaches the stopping level.
- Toilet won’t fill if water supply is on high
- Plumbing – Toilet Supply Valve Not Turning Off
- Toilet bowl cleaner container distorts flushing action
Best Answer
This sounds like a case with the bowl fill line that refills the bowl while the tank is refilling is the problem.
What may be happening is this line is low enough in the tube and when the float stops the incoming water flow it starts a siphon from the tank and once low enough it will refill the tank and start the cycle again.
The fix is cutting the tube off at the top of the pipe above the water line this will usually stop the siphon.
Many new refill valves actually have a clip that holds the tubing about a ~1/2” above the tube to stop this from happening.
Try ether cutting the tubing shorter or raising it above the water line and that should stop the siphon.