(Springfield, IL)  --  The Illinois Commerce Commission is giving Illinois American Water a rate increase, the third increase granted to the company in the last five years.  The company says the new rates will mean a customer with an average usage of 45-hundred gallons a month will pay about 40-dollars a month.  The increase means that the company has nearly doubled its per-gallon usage fees in just five years, from four-tenths of a cent per gallon in 2007 to nine-tenths of a cent per gallon beginning October 1st.