Greetings - This looks like the best resource website with proper forums and specific discussions - very nice. I did search for my subject at hand having not found anything. I have the misfortune of living in lower Delaware at the moment on land that I FORTUNATELY own. I have built myself a voluminous "TinyHouse" - The beginnings of a sloping little reservoir that a friend starting making prior to my arrival shows a watertable around 24" below relative grade. I trenched for separate electric lines and my domestic water supply. (Electric lines will be only 12"-18" below grade). I realize that the water table is separate from the frost level but am I installing piping in ground water still? Or should I risk it and lay in gravel, my perforated drain tube and then rest the waterlines just above? My plan is to build a block wall with berm so earth covering the lines will still end up being at least 24". I'm concerned about the ground water and how piping is supposed to be a minimum of 24" below grade or rather really 12" below the frostline of 24".
Hope some can lend advice or common vernacular practice.
This is one of those Rock and Hard Place situations. The frost line stops at the water table.
The concern is how to keep the water line from freezing, electric is not an issue except for plant roots or a shovel strike later on, not much will happen to electric wires underground.
What we need to discover is; does any portion of the relatively high water table freeze solid during the coldest winter days?
If it does then you would have the choice of using a deeper trench or building a good sized mound on top of the water line.
Well, State water maps shows true watertable at 3-6 ft below grade and sure enough, the water receded leaving a dry trench and reservoir. Good! I added gravel to the trench bottom, laid in perforated drain tube in sock, more gravel, then laid the waterlines in (right now just garden hoses until I can do hardpipe), more gravel, and then packed in with sandy soil and topsoil.
The rainwater that collected is more than 24" below grade so either way, I'm okay. Thanks for the question. The frontline for southern Delaware is 24" min. Building code requires the top of a footing to be 24" min below grade.
And septic is okay. The distance is short and as well will be deep enough. There is an existing system here that my family installed in 1989. Mound system, but I am considering to use for only grey wash-water and use composting toilet. Still working these details out.
Willie Smits: Village Based Permaculture Approaches in Indonesia (video)