Since owning them, we have installed features to store over 5,000,000 gallons of water in the soil that did not exist before.

The soil here was clay so the digging even with excavators where they could use one was challenging. 

I have started soil tests on 12 lots costing me a total of $5340 for the permits.

Welcome, @Sandy Blair!

In your new hole, supplant with a high quality mulch soil mix.

Than did all the red-tape fun to get things set, and completed soil corrections. 

I’d love to hear about environmental assessments, soil tests, and any other pre-development evaluations

Sandy, how did your case fizzle out? 

The main issue with rental basement is water if it has water issue usually it is a simple fix .Clean gutters ,discharge gutter  water away 10" away from foundation, make sure you foundation soil is slopped away from it .If you need to buy soil get a clay mix .Cut back any tree too close to the foundation look at the drip line that's how far the limbs are out from the tree .If all that is done still has water buy a sump pump  carry the water to day light away from foundation 10" to 15" .

@Sandee SampsonA construction attorney would be who to contact but you are going to spend a lot more than $7000 in getting this resolved against a builder.Also let’s say you win, the courts could also say you didn’t pay for a retaining wall which is needed so it’s a betterment to the property so you would still need to pay for the wall and they would be responsible for some soil etc.