The industries employed an estimated 6,049 people. Most of the businesses in Marshall County purchase their water from a PWS or obtain their water from a private supply not requiring a permit. There is one water use permit for industry in Marshall County. Currently there is one water use permit issued for power production in the county, which utilizes about 200 million gallons per year. Mining Water Use Mining in Marshall County consists of sand and gravel extraction.
Activity varies from year to year based upon construction needs.
Four water permits were issued for mining in the county. The State-Wide Rural Well Water Survey completed in 1989 indicates the following quality results for private well water, shown in Table 3, for the east hydrogeologic region in which Marshall County is located. The Iowa State-Wide Rural Well Water Survey, 1990. The UHL's test results for the county also show that in an average year 9.1 percent of wells tested for nitrates exceeded the recommended maximum. These test results are based on non-random samples.