My toilet burps air when flushed. The burp comes right at the beginning of the flush. The air is coming out of the inlet from the toilet tank. The air is NOT coming from from the trap/waste line.

Could this still be a problem with a clogged waste line or a clogged vent stack? Or is this a different problem?

2 Answers 2


Check the water outlet holes just under the front lip of the toilet bowl as they are being restricted or they are clogged. Put on a couple of gloves and use a metal wire coat hanger to clear the holes. I did this a couple of weeks ago to solve this exact problem. A couple of the holes were partially blocked while a few of them were completely blocked.


There is no connection between the waste line and the water inlet unless something has gone very, very wrong. Since there is no connection, there is no path for the waste line to cause any issues with the supply line.

Given that the water in the system is under pressure, I don't see any way that this could even be an issue with the toilet water valve. If the valve leaked, pressurized water would be coming out of it. Air would not be getting in. What is most likely happening here is that air is being introduced somewhere else in your plumbing, then accumulating in the toilet supply line. Finding the source of air might be quite a hunt.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.