With Gregg and Mark working grade in a deep hole, we installed Wolverton's 'graveless' (I mean gravel-less!) septic system using Infiltrator chambers and added some crates for additional leachfield space, over sand, water table suitable depth under, additional insulation and visqueen to keep the ground drier and less prone to freezing would have been better. Also more inspection pipes. Takeaway is get all the parts needed onsite, work out depths of tank and field, perhaps a lift station after the septic tank would have made the leach field at a higher and better elevation.