I know you are not supposed to plant trees, etc. over the leach field or nearby. This poses a threat to the field due to roots invading. Is there a safe distance away from the field to plant trees? A specific tree that can be planted? Fast growing shade trees should not be planted, at least from what I read, less than the future spread of the tree due to the roots requiring lots of water (i.e. spread 50 feet, distance to plant tree away from field 50 feet or more). therefore they seek out the field. Oh, I am in zone 5 or 6 with all clay soil and high winds at times (open fields). Thanks. oops, probably should have placed this in landscaping, but it all ties in.
Probably not the answer you want...but check with your local health department. More than likely, they should be able to tell you what's expected/acceptable.