Current data suggest total water use of 19,334 million gallons per year. Livestock production has declined in the county over the past 10 years. Some continued decline is anticipated in the next 20 years, resulting in less water consumption. Domestic water use during the next 20 years in Johnson County will rise as a result of a population increase and some increase in the per-capita consumption rate. Any future change in water uses for these sectors could have a large impact on total water consumption in the county.
Wells supply water for many communities, farms, and industries in east-central Iowa.
The water from these wells comes from deposits of unconsolidated materials and layered rocks whose characteristics are consistent enough to allow fairly reliable predictions as to their location and water-yielding potential. Rocks that store and transmit water are called aquifers. Within east-central Iowa, there are 3 separate surficial aquifers and 5 bedrock aquifers available for use as water supplies. The unconsolidated deposits near the land surface comprise the surficial aquifers. Underlying are layers of sedimentary rock collectively called bedrock.