OK Plumbers, here's one for you...?
Single story apartment. The toilet backs up on episode, almost to overflow, & the kitchen & sink drains run very slowly. I've put sulfuric sharp down the drains twice, once directly into the line beyond the trap. I've snaked the toilet & the roof vent & found no blockage. Finally I snaked the main sewage file but found nothing.
It behave like a vent problem but today I be going to install an under-the-sink vent & noticed something. While I have the trap off contained by the kitchen (which allowed plenty of air available for drainage), the bathroom sink drain be still sluggish. So I ruled out a vent problem - for now. I'm out of concept! Talk to me.
Answers: Do you know if the city has pressure or gravity sewage, or do you hold a leach line? It sounds resembling a pressure problem from the street side. You would have to contact the city, but they could install a vent earlier it reaches your house if the pressure is too giant on the street side to allow for proper drainage.
Keep in mind that most sea fixtures must be within 5 foot from a vent or they will not drain properly. (5 feet is code as well)
do the lines enjoy a slope to them going from the house to the outside where the sewage go. if not after that may be the problem.
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