- GoldenHas donated $ to the upkeep of GPL
Also is there another drain further “up hill” from the sink. I.E A laundry tub. If that drain also backs up then the problem is in the sanitary sewer line the two drains are on.
We used to get a back up when we had a lot of family up at the cabin. Laundry tub at the end of the line would also back up. I would fill sinks & laundry tub with water, pop the drains and use a plunger on the laundry tub. It had the most direct path and the pressure and water volume would then clear the pipe. Root cause was a low spot and it would collect tater peelings, veg. scraps, salad trimmings, etc. from big feeds being produced. It is a nasty azz crawl space so after 2 July 4ths incidents I went in with a pipe hanger & battery drill and lifted up the sag.
To much “fall’ in a sanitary pipe can be a problem. The H2O will run too fast and leave the “solids” behind. 1/8″ /ft is the rule and if a plumber needs to drop more than that they will run a clean out up and a straight drop down.