I have 3 toilets in the house. The one in the basement I recently (about 6 months ago) replaced so that they are now all 3 the same (american standard low flow). It was working fine until about 10 days ago. When I flush it the water stays in the bowl and then fairly quickly drains out until there is not enough water to fill the bottom. When it is draining I can hear the water draining. I have added water to the bowl and it too drains quickly down to the point where the bottom of the bowl is not completely covered. I have plunged it multiple times to no avail. Every once in a while it will flush (somewhat) but not as it did when I first put it in. I am the only one who uses this one (just the wife and I) and nothing fell into it. I do use a cleaning tablet (Clorox cleaner) that is in the tank (it dissolves over time) and it is not obstructing the flapper. We have owned the house for 22 years and this is the first time I have had an issue with any of the toilets.

  • Hello, and welcome to Stack Exchange. There's probably something in the drain wicking the water down. Commented Dec 19, 2016 at 15:37
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    I suspect a venting issue. But it could also be partial blockage in the main line since this is a below grade basement toilet. Also we learned the hard way not to use tank cleaners... Especially the Clorox branded version, they cause the rubber seals in the bottom of the tank to deteriorate more quickly. 5-10 years instead of twice that or more.
    – Tyson
    Commented Dec 19, 2016 at 23:50
  • Huge Bubble When Toilet Flushes, Why? Please see the how to clean under the rim link and my advice about installing a chain float in my answer there, after ensuring that the fill tube is where it should be (stuck down into the overflow) and operating properly.
    – Mazura
    Commented Dec 21, 2016 at 2:12
  • Ok, so the Clorox is gone. Good advice. I checked the 2 other toilets and after flushing the bowl does fill properly. However after the flush the basement one tries to fill but I can hear it draining out until the tank is full. The water level in 2 is 2 1/2 and when all is said and done it is about
    – Bob Ring
    Commented Dec 21, 2016 at 16:43
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    @mazura In doing more comparing of my toilets I discovered that the water flow from the fill valve through the fill tube was somehow clogged causing the water to come out sporadically therefor it was not filling the bowl. Once I replaced the fill valve/fill tube all was good. Thank you for your suggestions.
    – Bob Ring
    Commented Jan 6, 2017 at 18:48

1 Answer 1


If you have a plugged sewer vent or a plug in a line to the vent, then water can get sucked out of the trap in the toilet. I believe that this is the reason low water in the bowl occasionally occurs in plumbing that has no permanent fault.

I just poured a bucket of water into a properly operating toilet and the water drains down to a very low level in the toilet. So this is normal. The water supply system in the tank is supposed to continue a gentle flow into the bowl after the flush is finished to raise the level in the bowl to the height that the design of the toilet trap allows. In your malfunctioning toilet the water supply may not be directing the flow through the small flexible hose into the overflow tube. With the tank lid off compare a flush in the basement toilet to a flush in one of the properly operating toilets.

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    I would check the little tube that fills the toilet bowl after the vacuum break from being flushed. If there were other problems like a plugged vent pipe the toilet would probably gurgle as the water was pulled out.
    – Ed Beal
    Commented Dec 19, 2016 at 23:28

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