Is it feasible to have two inlet drains enter a septic tank? I'm helping a friend plumb a house basically from scratch. It's an old house that's been added onto a couple times, and it would be much easier to have two drains exit the house and each go straight to the septic. We're replacing existing plumbing so we didn't need to pull a permit, but we'd still like to be smart about it. Any advice would be great, thanks.