We have 4 toilets in our house. One of which for the life of me can't figure out why the water level in its toilet bowl is low. This particular toilet is a dual flush and it's located in the basement. It is worth noted that this is the only dual flush toilet we have in the house.

I have replaced both the fill valve and the overflow tube and have also tried to elevate the fill valve but nothing works. The toilet flushes just fine and there appears to be no leak. We have been in this house for 2 years now and decided it's time to figure out why.

After each flush, it seems the water rises to just a normal water level in the bowl, then it recedes a little bit after the tank is filled. I would appreciate any help here. Thanks.


  • No chance you have a leak in the toilet trapway?
    – Huesmann
    Jun 17, 2023 at 12:31
  • Will it have anything to do with the shut off valve or the water supply line? I'm trying to avoid replacing the toilet if at all possible. I have replaced the fill valve and overflow tube now, thinking of replacing the shut off valve and the water supply line before I go with the last resort of replacing the toilet. Just not entire sure if it's a worth a try?
    – Sicarius
    Jun 19, 2023 at 4:45
  • If it flushes satisfactorily, why does it matter?
    – FreeMan
    May 2 at 17:22

2 Answers 2


Are all of your same toilets the same manufacturer and model? If not, maybe this one just has a lower typical water level. Can you reach up underneath the exit and feel if the water level is at the top of the drain lip? Typically if the toilet fills normally then water goes down slightly, it's a sign that more water goes into the bowl from the flush than the bowl can nominally hold, so a bit flows down the drain to reach the level of the drain lip.

  • I forgot to mention that this basement toilet is a different make and model. It's the only dual flush toilet in the house.
    – Sicarius
    Jun 17, 2023 at 3:36

Water level in the bowl is determined by shape of the flushway. The level is not "too low" if manually slowly adding water to the bowl does not result in a higher permanent level. There should be an adequate dribble from the fill valve, down into the overflow tube to replenish the bowl after the flush has occured. Perhaps you need a different fill valve with a more generous refill flow. There are some valves that have adjustable refill flows.

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