Speedball or anyone who knows,

We are trying to design and build a small pool house that will have a bathroom and some kitchen fixtures. Question I have: To figure out the slab elevation (height), what is the vertical depth below the slab surface that the sewer rough piping must be installed below the toilet before it begins it horizontal gravity flow descent to the sewer line outside the slab.

I don't want a slab that sits 4' above the pool deck. But if the sewer rough is too deep, we can't get a gravity flow and will have to use an ejector pump to get it in the gravity sewer line. At least that's my thinking to this point. Any other ideas okay too...

Thanks in advance,
Masterofnone

PS. Sorry if this question has been answered before but I couldn't locate an answer after much searching.

A sewers depth is determined by the length of the run from the highest point, (the farthest fixture from the exit point) to the point it exits the house. It will slope 1/4" to the foot all the way down to the exit point. If the elevation's tight on your project you may reduce the slope to 1/8th inch to the foot but no more. Good luck, Tom