Just jumping in for a minute. Keith, I realize you have sewers, but has the property every had a septic system in the past? I lived in a house that originally had a septic system; after the city installed sewer lines we hooked up to the new system but the old septic tank was still in place with the lid (as
@porkpal mentioned) was just a few inches under the soil.
Use a piece of re-bar and jab it into the soil where the bare spot is and see if you contact anything hard like metal or concrete.
Okay, I'll go back to lurking now.
