Water out of toilet

[rb8jm]

I have 1.6 gallon flush American Standard toilet. The toilet suddenly just loses half of the water in the bowl, almost like someone partially flushed it. I walked past the bathroom and heard what sounded like water suddenly sucked from the bowl, looked in the bathroom and sure enough it did. I had just flushed the toilet just a minute before i discovered this strange occurrance.

I think I may have a venting problem. I have never seen this before.

[Redwood]

Is the toilet clogged?

Is it flushing properly?

[rb8jm]

Toilet isn't clogged and working properly

[Redwood]

If you are experiencing extremely cold weather you may have frost closure of the roof vent occurring.

[DaveSmith]

Sounds like the main water line is broken.

[hougie]

That doesn't at all sound line a broken water line since the bowl is empyting and not the tank. and there would be water all over if the line was broke. It's has to be something in the toilet itself, either something stuck or air pocket. If the roof vent was plugged air should gurgle into bowl and you will smell sewer gas.