The industries employed an estimated 1,865 people. Most of the businesses in Jefferson County purchase their water from a PWS or obtain their water from a private supply not requiring a permit. There are five water use permits for industry in Jefferson County. There is no power production in Jefferson County. Mining Water Use Mining in Jefferson County consists of sand and gravel extraction.
Activity varies from year to year based upon construction needs.
One water permit was issued for mining in the county. The Iowa State-Wide Rural Well Water Survey, 1990. The UHL's test results for the county also show that in an average year 21.9 percent of wells tested for nitrates exceeded the recommended maximum. These test results are based on non-random samples. The University of Iowa Hygienic Laboratory, Private Well Water Quality, 1990-1994.