Was also in Wisconsin. (Wausau area) The pump only ran in the early spring and after very heavy rains, which meant it sat for months on end without running. Again, I never had a problem.
Lived in the Northern, Central and Southern part of the State, and never heard the sump pit refered to as a crock. It was either a sealed or open sump. I thought a crock was something one brewed beer in! Guess I learned something new.