The industries employed an estimated 4,596 people. Most of the businesses in Johnson County purchase their water from a PWS or obtain their water from a private supply not requiring a permit. There are two water use permits for industry in Johnson County. Currently there is one water use permit issued for power production in the county, which withdraws about 12,819 million gallons per year. Mining Water Use Mining in Johnson County consists of sand and gravel extraction.
Activity varies from year to year based upon construction needs.
Five 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 Johnson 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 6.0 percent of wells tested for nitrates exceeded the recommended maximum. These test results are based on non-random samples.