I am adding a garage to my property. The earth is the same grade as where the sewer line exits the house. This is my question. The drain leaving the house is 38" below grade. The garage is 66 feet away fom the drain location. If I maintain a 1/4" per foot drop, the height, over 66 feet is a 16.5" drop. If I use this logic, the height of the drain, exiting the garage would be 21.5" below grade. Is there any way this is deep enough below grade for a sewer line? If I go to 1/8' per foot drop, I'll be 27.75" below grade. What is the best thing to do. I can build the yard up a bit, if needed, as well. Thanks Shawn

Shawn...

At 1/4" drop in 66 feet you will drop 16.5 inches as you stated with 21.5" below grade.

However, at 1/8" drop in 66 feet you will drop only 8.25 inches (1/2 of what it would be at 1/4") with only 13.5" below grade... right?

Seems to me you need to stick with the 1/4" per foot of slope to maintain maximum depth.

I have seen plenty of sewers at just 21.5 inches below grade, but I wouldn't recommend driving over pipes with trucks or anything like that.

Call your local plumbing inspector and ask him what he thinks about this... just throw it up as future project or can even call the next town over and ask that inspector what he thinks...

I think you are cutting this close and don't want you to have issues... call the inspector and see what he thinks...


MARK