How Water Reuse Can Address Scarcity | Article

Only 3% of Earth’s water is considered freshwater. Only 0.5% is readily available for humans. Freshwater is essential for human survival—for our drinking water, of course, but also to support ecosystems and enable key sectors of the economy such as agriculture to energy production. In the midst of climate change, freshwater resources are becoming increasingly scarce. Irregular rainfall and droughts diminish water supplies, while rising temperatures increase evaporation and evapotranspiration rates from lakes and rivers, further reducing available water. Additionally, the melting of glaciers, which serve as critical freshwater reservoirs and significantly contribute to downstream river flow, threatens long-term water availability for many regions, especially Arctic and sub-Arctic regions such as Alaska.

Given these challenges, water reuse can play a vital role in preserving our freshwater resources. Water reuse, or water recycling, is the process of treating and repurposing wastewater for applications such as irrigation, industrial processes, and even household uses such as bathing, cooking, and drinking. By promoting the conservation of freshwater sources, water reuse can help address the impacts of climate change on our water supply.

Types of Water Reuse

Water reuse can be tailored to the specific needs and resources of a community or region. Potable water reuse involves heavily treating wastewater from residential and commercial sources and sometimes blending it with other water supplies, such as surface and ground waters, to ensure safe and reliable drinking water. There are two types of potable water reuse:

Indirect potable reuse: Wastewater is treated at a wastewater treatment facility then pumped into a natural basin or reservoir where it is filtered naturally through the ground before being sent back into the water supply.
Direct potable reuse (or purified water reuse): Wastewater undergoes advanced treatment processes so it can be delivered immediately to the drinking water supply system without the need for an environmental buffer.

Non-potable water reuse, also known as water reclamation, recycles wastewater for uses that do not require the rigorous treatments necessary for drinking water standards. Common uses for reclaimed water include irrigation, industrial processes, and toilet flushing. Treating water to meet drinking standards requires significant energy use, but non-potable water reuse allows for a less intensive treatment process, lessening strains on energy resources.

A specific type of non-potable reuse is graywater reuse, which involves repurposing water from sinks, showers, and washing machines within the same building or property. This water is used again for applications like irrigation and toilet flushing without undergoing treatment elsewhere. It is important to note that graywater excludes wastewater from toilets, kitchen sinks, and dishwashers. These types of water are classified as blackwater, due to higher levels of organic contamination, and are not suitable for the environmentally beneficial uses associated with greywater since blackwater requires additional treatment to be safe for reuse. Graywater reuse reduces demand on freshwater sources such as rivers and lakes by providing alternative sources for non-potable uses.

Water Reuse Across the United States

More than half of U.S. states have already implemented policies regulating water reuse, with the strongest initiatives found in the West, where water scarcity is a chronic issue. The Los Angeles County Sanitation Districts operate one of the largest wastewater recycling programs in the world, providing affordable recycled water to over five million people. The Los Angeles Department of Water has implemented a Water Conservation Ordinance which has been instrumental in decreasing wastewater flows. These actions, alongside the promotion of other conservation initiatives by the county, have allowed the Sanitation Districts to streamline their focus to stormwater diversion as an alternative water source. To date, over 14 stormwater diversion projects have been established, diverting an average of nearly 439,000 gallons of stormwater per rainy day into the sewer system. Once the stormwater enters the sewer system, it is distributed to one of 11 wastewater treatment plants to be treated for non-potable and indirect potable reuse. These projects are funded by the Safe Clean Water Program, which is supported by a property tax. To encourage municipalities to participate, the Sanitation Districts have adjusted their sewer connection fees, making participation more economically viable for communities, especially those with limited resources. In California's 2024-2025 state budget, $73.5 million has been allocated for recycled water projects, reflecting the state’s commitment to addressing these critical issues.

Texas has also led the way with innovative potable reuse projects. The state has practiced water reuse for agricultural irrigation since the 1800s and is home to the first direct potable reuse project in the United States, located in Big Spring. Built in 2013 and operated by the Colorado River Municipal Water District, the plant produces about 1.5 million gallons of reclaimed water per day that is then mixed with regional lake water and sent to be treated to meet drinking water standards. Additionally, the city of McAllen, Texas supplies 3.5 million gallons per day of recycled water to the Hidalgo Energy Center, which generates 477 megawatts of energy for the surrounding area. Given the diverse needs of Texas’s unique ecoregions, and the fact that its population is expected to grow to 51 million by 2070, water reuse presents a vital strategy to sustain its growing population amid increasingly extreme weather conditions linked to climate change.

Water reuse projects are continuing to take off across the Southwest. This year, Utah’s Washington County received a $20.5 million grant from the Bureau of Reclamation to support a regional water reuse system. This funding is a significant step towards the county’s $1 billion project to build new and expanded treatment facilities, four new reservoirs, 60 miles of pipeline, and multiple pump stations. Zach Renstrom, general manager of the Washington County Water Conservancy District, emphasized how important this system will be in supplying the growing community with reliable water, stating that “every drop counts.”

Meanwhile, in 2023, New Mexico developed a 50-Year Water Action Plan that identified water reuse as a critical solution to addressing the state's water challenges. In 2024, New Mexico plans to create a consistent, science-based regulatory program for the treatment and reuse of produced water beyond the oil and gas sector (produced water is water that is brought to the surface during oil and gas production). In 2026, New Mexico plans to establish clear regulatory pathways for potable (direct and indirect) and fit-for-purpose non-potable reuse of all relevant sources of wastewater, including those from the domestic, municipal and industrial sectors. Both Utah and New Mexico’s projects will require additional financial support to ensure successful implementation.

Beyond the West, Florida stands out as a leader in water reuse projects, with an average reuse rate of 34% compared to the national average of 7%. Recent low-flow conditions in streams and rivers, combined with growing populations, has necessitated increased water reuse in the region. Florida's public access reuse systems are used to irrigate residences, golf courses, parks, and schools, highlighting the important impact reuse plays in supporting communities.

Additional Benefits of Water Reuse

In addition to providing a dependable source of water for local communities, water reuse offers numerous environmental benefits. Water reuse:

Decreases wastewater discharge, helping to prevent pollution from entering sensitive freshwater ecosystems.
Can create or enhance wetlands and riparian (stream) habitats, improving water quality, reducing flood risks, and providing essential breeding grounds for fish.
Supplements dried-up streams, helping to sustain and improve aquatic and wildlife habitats.
Provides nutrient-rich water for agricultural irrigation, reducing the need for chemical fertilizers.
Mitigates reliance on limited freshwater resources, reducing carbon emissions from water extraction, treatment, and distribution—all energy-intensive processes. Onsite water reuse in particular can help avoid the costs and emissions associated with transporting water to various sites.
Can create additional water treatment jobs, contributing to workforce growth and economic development.

Water Reuse in the News

Water reuse has recently gained attention from both Congress and the media. In May of 2024, the United States Senate Committee on the Budget held a hearing titled Droughts, Dollars, and Decisions: Water Scarcity in a Changing Climate. This hearing addressed the severity of water scarcity across the nation, highlighting how water reuse systems are a viable solution to diverse and pressing challenges facing various communities.

As part of the hearing, the WateReuse Association submitted a written statement further underscoring the importance of implementing robust water reuse systems as water supply and water quality challenges intensify throughout the nation. Investing in initiatives that promote the development of water reuse programs, such as the Pilot Program for Alternative Water Source Grants established under the 2021 Infrastructure Investment and Jobs Act (P.L. 117-58), can help build a resilient nation better equipped to tackle water scarcity issues.

Author: Jamiya Barnett