When it comes to recycling the most precious resource in the Colorado River Basin, Nevada blows the other six states out of the water, a new report has confirmed.
Researchers from the University of California, Los Angeles, combed through often-inaccessible wastewater data to show that Nevada leads the seven states with a rate of 85 percent reuse of its wastewater. With no standardized reporting across the country, that often meant calling individual treatment plants and asking for data.
“It’s not every day that Nevada has some serious environmental bragging rights,” said Mark Gold, a UCLA professor and director of water scarcity solutions at the Natural Resources Defense Council.

Arizona trails the Silver State as the second-most innovative, with 52 percent of wastewater reused. Wyoming and Utah were dead last, with 3.3 and 1 percent respectively.
California reuses about 22 percent. If it were able to recycle just 30 percent of its wastewater, it could increase its savings by about 993,000 acre-feet — more than three times the amount of water that Nevada is allowed to use from the river annually, according to the report.
As the basin trends hotter and drier with less available water than ever, the researchers call for state and federal governments to take closer look at water reuse as a solution, said Noah Garrison, a UCLA water researcher at the Institute of the Environment and Sustainability.
“The focus is always on: How do we preserve our allocation? How do we build more storage, which really is just going to take more water away from the river? It’s not creating new water,” Garrison said. “Wastewater reuse is one of a suite of practices that we absolutely need to be investing in if we’re going to meet these challenges.”
A symbol of excess, Las Vegas still leads
From the outside, it may be hard to believe that the glitzy resort destination nicknamed Sin City is so water-efficient.
But a 12-mile-long manmade river called the Las Vegas Wash has been a boon to water recycling efforts, carrying more than 200 million gallons of water back into Lake Mead every day. Much of that is treated wastewater from plants across the valley.
“Our indoor water use is a perpetual motion machine,” said Bronson Mack, a spokesman for the regional Southern Nevada Water Authority. “We could turn on every shower and faucet in every hotel room on the Strip, and it would not increase the amount of water we consume from the Colorado River because it is all being safely and sustainably returned to the lake.”
Dan Fischer, deputy general manager of operations for the Clark County Water Reclamation District, said the county reclaims nearly 110 million gallons of wastewater per day.
“All our wastewater must be treated to some of the most stringent standards in the nation. That is our job,” Fischer said. “We know the future of our community depends on it, so we’re always working to get better at how we do it.”
Much of Nevada’s success in figuring this out can be attributed to policy born out of necessity, said Gold, of UCLA.
The Colorado River Compact divided up the river in 1922, and Las Vegas then was a small fraction of the metropolis it has turned out to be. That’s why leaders gave the state only 300,000 acre-feet, the least of any of the seven.
Water sent back to Lake Mead generates return-flow credits, which grant the ability to use more water than is allowed by the compact. Those credits become increasingly important for Las Vegas’ rapid growth, with UNLV projections predicting Clark County will add 698,000 residents by 2040.
“In a place like Nevada, you’ve got no choice,” Gold said. “That incentive is always there because you just don’t have enough water to go around. Return-flow credits are a game changer.”
Call for action
The reason some states are so behind Nevada vary, the researchers said.
For some states, a lack of funding for billion-dollar projects or even strict state water laws can prevent wastewater from being reused. Sometimes, though, it’s a lack of prioritization, they said.
In the report, the researchers ask the Environmental Protection Agency to work with states on setting wastewater reuse goals, improving data collection and developing funding mechanisms for projects.
“All seven states need to start working together,” Gold said. “There’s nothing more essential in this world than water. It’s part of our infrastructure, and we’re not investing in it adequately.”
Some state-to-state collaboration has boosted recycling, with Nevada committing $750 million in 2021 to Southern California’s Pure Water treatment plant.
If states and the federal government boldly commit to wastewater reuse efforts, the researchers said, a total of 1 million acre-feet of water could be returned annually to the system within 10 to 15 years.
Contact Alan Halaly at ahalaly@reviewjournal.com. Follow @AlanHalaly on X.