Hi! I have a question about the drainage system in my home. The plumbing vents on the roof are ABS. Does that mean that the drainage system below my concrete slab foundation is also ABS?

That leads to the second question: The drainage system has a downward vertical displacement (bellied?) just before a Y-junction that goes in one direction to the master bath, and to a clean out in the other. This condition may have been there since the house was built, or was caused by excessive water running under the home due to how the land was graded. I have fixed the grading problem and the foundation cracks the water caused. I have seen via plumbing camera that the drainage pipe has standing water. It appears that when the water rises that the rising water can escape to the sewer. It has not been a problem so far because the main bathroom has been down for 30 years and the only water going through has been from the laundry room. We finally got the main bath tub operational and I have used it a few times. It drains very rapidly.

If the bellied pipe is not backing up sewage to the bath or laundry, is it safe to leave it that way? Would using septic tank bacteria in the pipe help break down toilet paper and human refuse more quickly to prevent a backup? Thank you for any help and advise you can offer.



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