I know my local code (UPC) requires that pressurized pipes be protected by sand (or clean fill?) before backfilling with dirt...
But, does anyone know if there is a similar requirement for drain pipes? I'm getting ready to do underground drains for my bathroom addition and I'm wondering if I can just backfill over the pipes with the dirt I dug up (after inspection of course), or do I have to put down a layer of sand under and/or above the drain pipes?
Also, I am putting in a two way clean out for the same bathroom addition. The pipe from the bathroom will be 3 inches, but the pipe it connects to in the yard is 4 inch clay. Can I use a 3" two way clean out, or do I need a separate clean out (matching the diameter of the pipe it serves) for each direction since one is 4 inches and the other 3?