Under footers? Through footers? Where to put the central house drain?

[Erin]

This is probalby obvious, but I'm just not seeing this at all...
How does the drain get out of the house and head to the septic?   

I know you have to plan carefully when locating drain stubs in the slab/floor, but does it go under the footers to reach the septic??

[ScottA]

You'll need that pipe to be fairly shallow so the septic tank doesn't have to be so deep. I'd run it through the footing about 4" below grade to the top of the pipe. You'll want to put a sleeve through the footing for the pipe to pass through. Use a short piece of the next larger size pipe.

[Beavers]

So the pipe doesn't need to be below the frost line? 

What's the minimum amount of slope you need?

I'm a little ways behind you in the building stage Erin, and was wondering the same thing. 

[MountainDon]

1/4" a foot

[Ernest T. Bass]

So the pipe doesn't need to be below the frost line? 

If you're worried about it, just put a few inches of XPS over it. We put a layer 4'' thick by 2' wide over our drain. Probably overkill, as there's other pipes around here just a couple inches below the ground with no insulation that never freeze..

[rwanders]

  Thought I would pass on an experience I recently had---A few days ago I "commissioned" a new septic tank after several months of freezing and sub zero weather.  None of the drains would drain---mild concern ensued and I removed clean out near the side of the cabin----now mild panic ensued because the 3 inch pvc pipe was full of ice!  My god, I thought how could that be---the plumbing had never been used---I had only turned on the well pump just that morning. I immediately thought----the entire 1000 gallon tank must have somehow filled with water and was now frozen solid. We then cut the pvc line sloping down from the cabin plumbing and, it too was full of ice!  Now the plumber that was with me was also flabbergasted---even if the tank was full it was buried 10 feet and how would water in it back up 2 feet above the ground? We got the ice out of the sloped line and turned up my tankless heater to 140 degrees and left the clean out cap open and proceeded to let the hot water work on the ice in the lines. After about 15-20 minutes of that we used a 18" bar to chip at the ice through the clean out. Suddenly the drain opened up and flowed freely.  We finally figured out what happened----when I had the sheetrockers/tapers/painters in, they had been running a dehumidifier for several days in very cold weather and the slow trickle of water going down the shower drain had glaciated in the line finally blocking it completely.  Great sighs of relief from me!!  In normal use, even in Alaska. a 3 or 4" drain would not freeze like that----it did illustrate a potential problem if you have a very slow trickle in sub zero weather.