All the buildings also have evidence of ground water problems that have been minimally addressed.

In addition, you are still on the hook if the contamination spreads into the ground water or onto your neighbor's property down the road.

That is not particular to ground water contamination.

Second concern is ground water , if any .

I'm sure you'll work out how you deal with the contractor part so I won't comment there.Drainage issues: #1, Identify the source of the problem:Gutter/solid surface water pooling near the houseGeneral grading issues allowing surface water to run towards the houseHigh groundwater tableUnderground water conduit towards the house (solid rock, old abandoned pipes, etc)#2, Identify the solution:Gutter/solid surface pooling - simple - move the water away from the house.General grading issues: sometimes simple, sometimes expensive.

Most insurance doesnt cover ground water damage to foundations I think. 

He also does drone crop coverage for mapping fertilizer application yields & also field mapping to identify ground water drainage needs.

Then sadly in that 2 weeks the inspection supposedly came back with ground water/soil contamination.

More regarding the long term water outlook in California:"The Water Replenishment District of Southern California, which manages groundwater for parts of the region, has set a goal to wean itself off imported water altogether by treating and recycling wastewater and collecting more stormwater."

We have a little 3" pump we rotate on parcels in Columbus county where groundwater polution (farm runoff) seems to be more a problem than saline.