I have one toilet that overruns when flushed, and gurgles and bubbles when the other toilet is flushed. The one that started overflowing is seldom used so guessing this just started within the last month. The one that overruns does go back down to normal water level after a couple of minuets.

You have a partial blockage in the main drain line. Either pull toilet and snake the line or call a plumber.

Three or four buckets of cold water in both toilets may sufficiently clear any possible blockages, partial most likely, in the sewer lines. If not the next step is to snake your lines, and or air vents.

Hello terriwshu,

Please open the links below will give you and idea how to snake through the vent pipe as the experts above suggested, Thanks.

John


https://www.youtube.com/watch?v=TL-AJ_CwznM

https://www.youtube.com/watch?v=ZTJVn3vso8k