Who do I call to find out what a water table should be on a piece of property before I build a house?

I bought two lots in Markham, Illinois and I'd like to build my new home on them. I was told to find out what the water table is in that area but wasn't told how to. The city provides water in the area, but there is no sewer. There was a septic tank on the house previously there. I need to find out what the water table is and if it would be okay for a basement before I build. The home that was there before had a crawl space that the owners eventually lifted the house over to make a full basement. Is a water table the same in an entire city or is it broken down in sections? Also, what are some of the other things I need to look into before I build on the land to know if it's okay. Please help. :o{