The DEQ has primary enforcement authority in Michigan for the Federal Safe Drinking Water Act under the legislative authority of the Michigan Safe Drinking Water Act. As such, the division has regulatory oversight for all public water supplies, including approximately 1,500 community water supplies and 11,000 noncommunity water supplies. In addition the program regulates drinking water well drilling. Michigan has more households (1.12 million) served by private wells than any other state, with approximately 25,000 domestic wells drilled per year. The DEQ also investigates drinking water well contamination, and oversees remedial activities at sites of groundwater contamination affecting drinking water wells.