The University of California, Los Angeles ranked Nevada as the most efficient of the seven states that derive water from the Colorado River Basin.
The UCLA report analyzed wastewater data to make its conclusions. As there is no standardized reporting of water use, the university compiled data through various means, including phone calls to treatment plants. The Silver State was found to reuse 85% of its wastewater.
Nevada is followed by Arizona, which reuses 52% of its wastewater. Wyoming and Utah tied for last. The former recycles 3.3%, and the latter recycles 1%.
California, the heaviest water-user, was found to reuse 22% of its wastewater. If the Golden State recycled 30% of its wastewater, savings would increase by 993,000 acre-feet. This equates to more than three times the water Nevada is allotted from the river annually.
The Las Vegas Wash carries more than 200 million gallons of water to Lake Mead daily. A large portion of the water entering the wash was previously treated from various plants. The Clark County Water Reclamation District claimed 110 million gallons of wastewater in the county are reclaimed every day.
Nevada’s high reuse quantity stems from a necessity. The Silver State was originally granted the lowest allocation of river water when it was divided in 1922. The state’s rapid growth put strain on its limited supply. As Las Vegas continued to grow, it became more apparent that abundant reuse infrastructure was necessary. Water returned to Lake Mead generates return-flow credits, which are crucial in sustaining Las Vegas’ growth.
As the basin continues to become hotter and drier, researchers are encouraging additional water reuse. (Source)