The agent told me it’s normal given that OKC is on red soil (or something along that line).

. ~27k was put in escrow for removal and soil remediation.Current Scenario:After removing the tanks, the oil tank company hired by seller determined that the remediation is more substantial then estimated.

I say for any structure plan about $125-175/sqft this exclude well, septic, foundation that is additional cost and each one of those can range between 10-30k dependent on soil type depth need to drill and the type of foundation needed to support the structure.I have an Architecture and engineering background feel free to touch base anytime you want. 

Agreed with @Raymond Temprano -- it is definitely situational/Here in Colorado, especially in the Denver area, it's not uncommon to see settling in the soil because of the bentonite clay.

There have been a number of instances where he has had difficulty returning to his apartment and has soiled himself while in the common hallway.

It looked like hell and it took several hours to dismantle, grade out the soil, straw and seed the area. 

No person owning or having the care, custody, or control of any dog or cat shall permit said dog or cat to soil or defile or commit any nuisance upon any sidewalk, street, thoroughfare, wetland, in or upon public property or in or upon the property of persons other than the owner or persons having the care, custody, or control of such dog or cat, unless said person picks up any such waste and disposes of it in a sanitary manner.

@Sandy Sawyer thanks for the advice and fun analogy! 

@Sandy SawyerThank you Sandy!

@Sandy Gabin thank you!