When I flush my toilet, the bowl fills almost completely (but does not overflow) before the water finally empties out. The bowl then refills to a normal level and stays there until I flush it again. All of the original contents of the bowl are flushed out, but it definitely requires much more water than expected to make that happen.

I'm wondering if the issue is with the toilet itself, or with the drain line. Replacing the toilet is simple and cheap enough, and that would be my first route. But I'm also wondering if the drain is partly blocked, causing water not to exit the toilet until a large volume has built up inside the bowl.

The house in question is a foreclosure and had been vacant for over a year, for what that's worth. It was apparently winterized prior to being abandoned (and they appear to have put antifreeze in the toilet bowl), but I have no guarantee that the winterization was done fully or properly.

Any thoughts?

  • 3
    Note that there is no valve or restriction or anything like that stopping the water in a toilet from leaving. It's simply a loop in the toilet that starts a siphon effect when the water is higher than the loop. So, if water doesn't drain, something is blocking the flow.
    – JPhi1618
    Commented Jun 12, 2019 at 17:04

2 Answers 2


To me this sounds like a partially plugged toilet. A toilet auger will probably clear the problem up unless the drain has been sanded. A toilet auger is a short heavy duty snake made to clear the U bend built into the toilet. I have seen bad renters put sand in the drains of a home this makes clearing the blockage tough as the sand keeps falling into the U bend or trap, but it sounds like a blockage close to the toilet is your problem, once the pressure or water level is high enough the natural siphon takes over and clears the bowl.


This could be a, new problem as a clog in the line or roots.Is this a septic tank ? Inspect tank at clean outs. Or there may have always been a vent to small and water goes down slow. Look for vent pipe on roof. Check toilet pipe should be 3 inch.

  • 1
    There is another toilet in the house (on the first floor; the problem toilet is on the second story) that flushes without issue, so I assume the main drain line is good. I'll check the vent, though. Commented Jun 12, 2019 at 16:16
  • 1
    Does the tub ,and sink drain fine?
    – user101687
    Commented Jun 12, 2019 at 16:21
  • Yes, all other fixtures appear to drain fine. Commented Jun 12, 2019 at 23:53

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