A new report from the UCLA Institute of Environment & Sustainability and NRDC (Natural Resources Defense Council) demonstrates the importance of wastewater recycling for the mitigation of the outsized and much-litigated water demands placed on Colorado River. Recycling treated wastewater is a safe, reliable, sustainable, cost-effective key for ensuring a climate- and drought-resilient future in the West. But while certain states, such as Arizona and Nevada, lead the charge in wastewater reuse, most other basin states have yet to meet the moment.
Increasing temperature and aridity has led to less and less water available for extraction from the Colorado River each year, a trend that jeopardizes the natural ecosystems and 40 million people across the seven basin states (Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming) that rely on its supply. Consequently, the practice of large-scale wastewater recycling in these states has never been more important.
The fate of the Colorado River and the 40 million people, cities, tribes and businesses that rely on its flows would improve markedly if all basin states increased their water reuse to 40-50%
"We're facing a hotter, drier future and we need to pursue water recycling aggressively if we're going to ensure a sustainable, resilient water supply for the Colorado Basin,” said author Noah Garrison, a water researcher at UCLA’s Institute of the Environment and Sustainability. “Even recycling 40 percent of our wastewater could make a dramatic difference, and we have two states already above 50 percent showing this is an entirely feasible solution.”
Despite the importance of wastewater recycling, it remains an underutilized tool in sustainable water management throughout the basin. The total percentages, by volume, of wastewater recycled in each basin state are as follows:
- Nevada (85%)
- Arizona (52%)
- California (22.5%)
- New Mexico (18%)
- Colorado (3.6%)
- Wyoming (3.3%)
- Utah (<1%)
As a tool, wastewater recycling will be key for the sustainable management of the Colorado River and its major reservoirs, which demands diversion cuts of up to 3.9 million acre-feet per year (AFY). If all basin states were to reach a minimum reuse threshold of 40% of wastewater influent, the availability of recycled water—and resulting reductions to river diversions—could increase to nearly 900,000 AFY. Bumping this threshold to 50% of wastewater influent would increase water supply by nearly 1.3 million AFY.
“Investments in wastewater recycling facilities and practices provide reliable and resilient water supplies for the states and the municipalities they serve,” says Mark Gold, an author of the report and director of water scarcity solutions at NRDC. “The fate of the Colorado River and the 40 million people, cities, tribes and businesses that rely on its flows would improve markedly if all basin states increased their water reuse to 40-50%.”
To encourage wider adoption of wastewater recycling technology, the report recommends both federal and state-specific actions, including federal oversight and data collection methods, increased federal funding for water recycling projects, the establishment of state-wide goals and timelines for adoption (including strategies for meeting 30%, 40% and 50% reuse thresholds), and the development of formal state policies to eliminate barriers and increase wastewater recycling, among others.
