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Show To quantify the reduction in water use that may be realized from metering the additional 0.1 percent of connections, it was assumed that all unmetered connections are residential with an average indoor water use of 110 gallons per capita per day and an average outdoor water use of 3.5 acre- feet per acre per year. Rate structures and billing procedures base costs on the amount of water used. It was also assumed that secondary water use on these systems is negligible and the average lot size per connection is 1/ 5 acre. Current indoor water use for the unmetered population of 7,600 was estimated to be 940 acre- feet per year. Current outdoor water use for 3,150 connections was estimated to be 2,200 acre- feet per year for a total of 3,140 acre- feet per year. Unmetered systems could realize an estimated 630 acre- feet per year assuming water use is reduced by 20 percent. The water use and water savings estimates provided are, therefore, a maximum, and they may be reduced slightly based on the types of connections that are reported as unmetered. Costs to Meter Unmetered Connections A cost estimate for metering the estimated 3,150 unmetered connections was prepared based on data from the city of Denver between 1987 and 1993. The average installation cost is estimated at $ 500, resulting in a total estimated cost of $ 1,632,000 to install 3,150 meters. This cost assumes meter installation only and that all existing piping is acceptable. The estimated annualized cost per meter for installation is about $ 38 a year, assuming a meter life of 20 years and an inflation rate of 4 percent. The estimated annual cost per connection to maintain a billing program based on actual water use determined by meter readings is $ 12. The estimated total annualized cost is $ 50 for meter installation and meter reading and the billing program. The result is a cost of about $ 248 per acre- foot for the water savings that may be achieved assuming water savings of 630 acre- feet per year by metering the 3,150 unmetered connections. Of the three water use sectors studied, the M& I sector is the most regulated. Water Metering or Measurement in the Agricultural Sector Background Agricultural systems include irrigation and canal companies, water users associations and private water users. State water right laws and regulations require the measurement of water at points of diversion. The Utah State Engineer's Office ( Division of Water Rights) is responsible for the administration of these laws. River commissioners are hired by the Division of Water Rights to perform these tasks in the various river basins. ( Water users provide funds to the state engineer to pay commissioners.) Metering or Measurement Options Metering occurs mainly on pressurized systems because it requires water be delivered at least partially through a closed pipe system where meters can be installed on a full flowing pipe. Propeller or turbine type meters are available in many pipe sizes with a broad range of costs, but they can only be used with water that is clean or filtered from particles and other debris. Also, the maintenance costs of these meters are prohibitive. Magnetic type meters are not affected by sand particles and debris, but they are costly. Venturi shunt meters ( VSM) are available in 6-, 8- and 10- inch diameters with costs ranging from $ 450 to $ 650. The VSMs are an accurate meter with generally lower maintenance costs than propeller or turbine type meters. The VSMs are designed for clean water, but if they are installed vertically they can be used with water containing some suspended clay and silt particles and limited amounts of sand. 29 |