Utility Sink Issue
Have a basement sink that backed up about a week ago. After removing the water by hand two rounds of drain cleaner were applied. I now find that water is now coming up in the sink on its own. every other day the sink fills which suggests that the drain cannot be blocked. This water is coming up against gravity. Looking for guidance on what could pressurize water to come into the sink against gravity.
A line is plugged downstream of more than just the sink. When another higher fixture drains, it is backing up into the sink instead of running down the main line.
You have taught yourself a good lesson. Inspite of the TV commericials, liquid drain cleaners don't work. Moreover, you have possibly created a hazardous condition for the plumber that you will need to hire to properly clear the clog. Be sure to tell him what you used.