Once the soil in the area of the drain field is plugged up, there's not much you can do besides move it to another area or dig out the dirt and replace it.  

We rototilled the ground and amended the soil. 

So, I would just tell them that it is not made for the weight or the heavily soiled/dirty commercial items or the cleaning solvents that are on the commercial items she was washing when you visited. 

It's a garden.... they aren't trying to build a deck and patio out back.. it's soil and seeds.

It would be nice to find out if there is an ongoing issue, soil issue, ground water issue, etc. prior to making a final decision.Kind regards,Arpad 

if its an older home with cast iron soil pipe the soil pipe flange was leaded in and they can deteriate over time and fail. 

Is it still necessary to test the soil surrounding the tank to determine whether contamination exists?

I wouldn't be surprised if they tell you to pound sand. I

They left the unit in very bad shape (holes in walls, cigarette smoke smell, soiling and damage from unauthorized pets, graffiti and intentional damage, unflushed turd and vomit in the toilet, drug paraphernalia and liquor bottles, disgusting furniture and trash left behind, fridge, dishwasher and oven looked like crime scenes, cockroaches in the cabinets, grease down the drain, literally the works).

I was told 170$ repair permit and 400$ soil test.Instead of repairing field lines i am inclined towards connecting to county sewer tap do i still need to pay repair permit 170$ and soil test fee for 400$Please advisePlease advise