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5.0 Water Supply and Demand The major components of the various water systems were analyzed to determine existing performance and future needs, both as a joint utility and individually. Water supply and demand was the first quantity examined. Historical data showing water pumped in previous years provides a useful tool for predicting future water demand. The last five years of well pumping data for each city was reviewed in order to establish general trends and per capita use. Water demand projections are based on average historical water use patterns from 2009 to 2013, along with expected population growth for the region. Most of the data is from city documents such as comprehensive plans, DNR Water Conservation Plans and DNR annual reports. Missing data was estimated on a case by case basis. 5.1 Well Supply Requirements Well supply or production is a measure of the water system's ability to supply water needed to sustain demand. Per "Ten State Standards" a water system should be designed with sufficient firm capacity to supply the peak day demand of the system. Firm capacity is the amount of water that would be available if the highest capacity well was out of service (in case of maintenance or emergency). Peak day demand is the day of highest demand over the course of a year. It is usually calculated as a multiple of the average day demand based on historic trends. This is a key factor in understanding the potential benefit of a Joint Utility. In a Joint Utility fewer wells are needed to meet firm pumping capacity. As independent cities each would require one extra well to meet firm pumping capacity. In a Joint Utility those same six communities would only need one extra well to meet firm pumping capacity. 5.2 Unaccounted-for Water Use Water systems lose water through leaks in watermains, flushing, or other un -metered activities such as firefighting, street cleaning, construction, unauthorized water use and improper meter calibration. The amount of water pumped will always be greater than the amount of water sold. The Minnesota Department of Natural Resources (DNR), which regulates groundwater appropriations, recommends that the amount of unaccounted water should be less than 10% of the total water pumped in order to minimize lost water. For this study each city's unaccounted for water use was assumed to remain constant and meet historical averages through the future study period. Figure 5.1 shows unaccounted for water as a percent of total water pumped from the most recent five years of data available for each of the six cities. As a joint utility, the amount of water unaccounted for is less than 10%, meeting the DNR benchmark. However, some cities have unaccounted water greater than or close to 10%. It would be beneficial for these cities to begin taking steps to reduce the amount of unaccounted water regardless of whether a joint utility is created or not. Joint Water Utility Feasibility Study 15