Southern Nevada Water System - Source Water Assessment

The Safe Drinking Water Act (SDWA) was amended in 1996 to require states to develop and implement source water assessment programs for existing and potential threats to the quality of public drinking water, and to include a summary of that assessment in the water system’s annual consumer confidence report. Specifically, states are required to delineate the sources of public drinking water, identify potential contamination sources within the delineated area, assess the water system’s susceptibility to contamination and inform the public of the results. These results are summarized below:

The surface water source assessment includes an analysis of the current water-quality data at the intakes and the vulnerability of the intakes to potential contaminating activities located within the Las Vegas Valley watershed. The vulnerability analysis includes the time of travel from potential contaminating activities to the intake, physical barrier effectiveness of the watershed, the risk associated with the potential contaminating activities and evaluation of historical water-quality data prior to treatment. It is noteworthy that this study represents an initial survey of the drinking water intakes’ vulnerability and is based on land use in the watershed rather than an analysis of the drinking water. Even before undergoing treatment, water quality at the Southern Nevada Water System intakes is within state and federal-drinking water standards except for microbiological contaminants naturally found in all surface waters.

The vulnerability analysis of land use shows that the potential contaminating activities with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gasoline stations, auto repair shops, construction and wastewater treatment plant discharges. Based on water-quality data (prior to treatment) and the results of the vulnerability analysis of potential contaminating activities, the drinking water intakes are at a moderate level of risk for volatile organic (VOC), synthetic organic (SOC), microbiological and radiological contaminants and at a high level of risk for inorganic (IOC) contaminants. All of the Las Vegas Valley governmental agencies coordinate their watershed management programs to minimize the vulnerability risk to Lake Mead. The findings of the source water assessment will be used to enhance those programs.

The treated water delivered by the Southern Nevada Water System meets or surpasses all state and federal drinking-water standards.

For additional information, please contact the Nevada Division of Environmental Protection at (775) 687-9520.