Pool backwash question.

Hi Y'all,
Not sure this is in the right subforum but here I go anyway. I'm entertaining getting a pool built and I was wondering how the backwash discharge is handled when your on a septic system so that there's no sewer system to tie into. I'm just guessing it gets discharged to the ground which would make a DE filter undesirable. I would also assume having a salt water pool would be a bad thing if it's just discharged to the ground. Can someone with a pool out in the country educate me about this?
Thanks.