Right, Thesa. The drain field is the big problem, I see many folks have livestock in pastures where the fields are and wonder why the system has problems. Winter weather and soft ground can pack the dart over the field and case problems. The new sand systems have many more working parts and these can have broken pumps. The tank is only part of the system. But the city folks that are the lenders feel a empty tank at closing, within a short time before closing, is at least this items has been checked by someone to be working right. But standing water near the drain field when I'm there as appraiser, just before closing, could be a major problem. It's a cost the seller should pay, not the new buyer.
HLR a rural appraiser that sees the problem all the time.