My septic field is about 200 yards away from the well. The tests done at installation show that it takes about 1 year for the waste water to "percolate" back down to the water table, by which time it's all clean again (I DO have it tested, you know!)
So it only costs me the electricity to pump it out of the well, gravity takes it back down, and I recycle every drop of it. I could run the water all day long down the drain and not waste any of it ... !
Sometimes living out away from town has quite a few advantages ...