Almost all of them said that they legally have to do soil testing. 

@Demjan Van Der Kach @Sandy Uhlmann Sandy is right, there are lots of funds out there and most of them are legit.

Lead dust  is in the soil in old industrial neighborhoods and can easily be carried into the home and blown onto window sills and troughs.     

Department of Planning and Development should be able to guide you and they have reference materials available.Also, you can consult with an Enginerring company (land development) as they are quite familiar with zoning, impact fees, drainage, utilities, etc.Then there is soil testing, trench compaction & densities which can be handled by a geo tech firm.

That same property ON the sand is worth about $3.5 M.

I frequently read of "Texas soil issues" with regard to foundation problems.

Do you have soil testing results for this land? 

Some counties now depending on poor draining soil will require certain advanced systems.

If you are located on shallow soil with lots of bedrock, building with a basement is both costly (drilling, blasting) and unwise {water often does not drain well from a rock bowl).  

@Sandy Uhlmann Most of these questions depend on state statutes.