The industries employed an estimated 894 people. Most of the businesses in O'Brien County purchase their water from a PWS or obtain their water from a private supply not requiring a permit. There are no water use permits for industry in O'Brien County. There is no power production in O'Brien County. Mining Water Use Mining in O'Brien 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 State-Wide Rural Well Water Survey completed in 1989 indicates the following quality results for private well water, shown in Table 3, for the northwest hydrogeologic region in which O'Brien 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 56.7 percent of wells tested for nitrates exceeded the recommended maximum. These test results are based on non-random samples.