I have a small trickle into a toilet bowl that I'm trying to stop as it's causing rust lines and wasting water. The flapper is relatively new and I ran my finger along the edge of the valve rim to see if there was anything abnormal and it seemed smooth to me. Any other suggestions on where to look for the source of the problem?

Update: I've replaced the fill valve and the trickle is still there. Going to replace the flapper and scrub the flush valve rim with fine steel wool before assuming the flush valve needs to be replaced.

Update: That seems to have fixed it.

  • 1
    Stop valve set too high and is going down the overflow tube??
    – Jack
    Aug 14, 2016 at 15:42
  • Thanks. Float level seems fine, no water going down the tube.
    – MarcGuay
    Aug 14, 2016 at 16:37
  • The flat rubber seal under the fitting for the flapper where the tank and bowl connect may be where the leak is. They are not easy to change, we bought a new toliet.
    – Tyson
    Aug 15, 2016 at 1:18
  • @Tyson That sounds like it would cause a leak onto the floor behind the toilet rather than a trickle into the bowl, unless I've misunderstood you.
    – MarcGuay
    Aug 15, 2016 at 13:54
  • Correct, but it didnt. Finally called a plumber after replacing basically ever other part. He used a modified 60cc syringe to add dye to the bottom of the tank, which was almost immediately visible in the bowl. At that point the flapper was new. His price to disassemble was high, we paid his service call fee and went to home depot and bought a new toilet.
    – Tyson
    Aug 15, 2016 at 14:01

1 Answer 1


A leaking valve can also cause this kind of leakage rust, scale & small gravel can also cause the valve to leak. Some valves can be easily disassembled with the water off. A cup or glass put over the top and the valve turned on to flush the debris out. Reassemble with the water off and see if this helps. The float adjustment would be a quicker check as @jack suggested+. a video on how to flush a kohler fill valve. this is really quick and just 1 of several ways to clear the debris out. Some also have 4 screws on the top those you need to take apart and flush with the cup. some have tabs that when pressed in release the cap. Not all valves can be cleaned and some like fluid master can be pulled off the stem and a new valve installed in seconds. I hope this additional information helps.

  • Thanks. Float level seems fine, no water going down the tube. I don't understand your suggestion regarding the cup. How can I tell if the valve can be disassembled?
    – MarcGuay
    Aug 14, 2016 at 16:36
  • many times the top of the valve can be twisted 1/4 turn (or more) and the top will come off then place a cup over the top because when you turn the water on the spray just might hit the ceiling.
    – Ed Beal
    Aug 18, 2016 at 22:34
  • Gotcha. I was confusing the flush valve with the fill valve.
    – MarcGuay
    Aug 19, 2016 at 16:20

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