[unclebilly]

Up until the early 70’s, it was pretty normal to use a buried old car as a septic system. You would basically run the septic line out into the buried can and then the effluent would percolate up (or down) from there. Bigger facilities might have gotten something bigger like a school bus.

Then septic tanks an leach fields came into play.

https://www.homesteadingtoday.com/threads/septic-tank-or-something-else.316574/