Estimating Indirect Cost of Urban Water Use

Approximate quality-related indirect costs to urban water consumers are estimated to range from about $25/acre-ft (2¢/m³)/100 mg/l total dissolved solids to –35/acre-ft (2.8¢/m³)/100 mg/l total dissolved solids. These costs correspond to the lower and upper ends of the 200-mg/l to 800-mg/l total dissolved solids scale, respectively, generally applicable to the Los Angeles River Basin, in which the total hardness content of the unsoftened water is approximately half of the total dissolved solids content. Industrial water usage is about 20% of the total urban usage, for which annual per capita consumption is approximately 0.2 acre-ft (250 m³). Composite and component cost curves are presented which consider deterioration of domestic plumbing, domestic water heaters, and municipal waterworks equipment, industrial water treatment costs, and domestic and commercial costs for contending with water hardness.