July 17, 2003

Reclaimed water — a ‘new’ water supply

  • Treated wastewater used for irrigation, industry and the environment
    Department of Ecology

    Cochrane Park in Yelm
    Photos courtesy of Department of Ecology
    At Cochrane Park in Yelm, reclaimed water is stored in this pond.

    Nature’s water cycle has been reclaiming water and returning it to use since the beginning of time. Although the earth has remarkable restorative powers, these natural cleansing processes are slow and under ever-increasing demands.

    Water simply is not always available at the right time, in the right place, in the right amount, of the right quality, for the right purpose, to meet human and environmental needs.

    At the same time our population is increasing in Western Washington, global warming models predict that snow pack in the Cascades will continue to decrease. With less snow pack, less water is available in our rivers and streams during the critical summer months when in-stream needs and human water demands both peak.

    Periodic droughts further emphasize the need for a reliable water supply. Reclaimed water is a powerful tool to provide that supply.

    What is reclaimed water?

    Under state law, reclaimed water is considered a new, basic water supply similar to surface or ground water. Reclaiming is the process of using technology to treat wastewater to a quality that restores the value of the water. The overriding goal is to efficiently return the water to beneficial uses, such as irrigation, industry and environmental enhancement.

    The fact that the water is expected to be used distinguishes reclaimed water from treated wastewater effluent, which is discharged to the environment under conditions that will minimize environmental harm.

    Anyone who generates reclaimed water needs a permit from the Department of Ecology. The permit controls the conditions of treatment and use, including water quality, location, rate and purpose. It gives the permit holder the exclusive right to use and distribute the water generated.

    Who benefits?

    Water is essential to sustain life. Throughout history, investments in water and wastewater infrastructure have been central components of successful civilizations.

    In passing the Reclaimed Water Use Act, the Washington Legislature recognized the importance of reclaimed water to our state’s economic and ecological well-being. It stretches our water supplies to meet the increasing demands of irrigation, industry and agriculture, saving drinking water for drinking, and preserving in-stream flows for fish, wildlife and recreation.

    From a big picture perspective, everyone on the planet benefits from the use of reclaimed water.

    Why hesitate?

    Although we, as a society, recognize the relationship of our ecosystem to our economy, the value of water to our quality of life, and the power of technology and innovation, we still hesitate to embrace reclaimed water as a solution.

    Why? Part of our hesitation may be due to the inertia that always precedes a major change. We have lingering concerns over the cost of reclaiming water. There are issues of perceived risks and liability that must be addressed.

    Yet reclaimed water is highly engineered, more predictable in quality than many of our existing surface and ground water sources. State law actually requires consideration of the feasibility of reclaimed water in both wastewater and water supply planning (RCW 90.48.112 and 90.46.120). It says reclaimed water should be used to the extent it is appropriate for beneficial uses. We have an obligation to weigh the risks of inaction against the costs of action.

    The cost of action

    While reclaimed water infrastructure can appear cost prohibitive on its face, this perspective typically does not accurately reflect the total costs and benefits. Value is not limited to the sale of reclaimed water, but also includes the value of water not diverted or extracted from ground or surface waters and reduced water quality impacts from wastewater discharge.

    A cost analysis should compare the total cost of reclaimed water to the total costs of the alternatives. In doing this, it is important to note that the costs of both wastewater treatment and new water supplies will continue to rise. These costs may include all of the following:

    • Obtaining water rights, if available, for future new supplies.

    • The reliability of the new water supplies during times of drought.

    • Constructing storage and transmission facilities.

    • Siting and constructing or upgrading existing water supply treatment and distribution systems.

    • Siting and constructing or upgrading existing wastewater treatment facilities and outfalls.

    • Mitigating environmental impacts.

    • Economic impacts of delaying development or attracting an industry.

    • The cost of retrofitting for reclaimed water supplies at a future date.

    It is important to begin assessing the options as early in the planning process as possible to assure coordination of wastewater treatment, water supply and other planning processes.

    Who is using reclaimed water?

    Reclaimed water is used for irrigation at Sequim’s Carrie Blake Park.

    There are currently 16 reclaimed water facilities operating within the state of Washington. Uses at these facilities include crop and landscape irrigation, toilet flushing, dust control, construction water, industrial cooling, created wetlands, groundwater recharge and stream-flow augmentation.

    Reclaimed water projects in the Puget Sound area are planned by the LOTT Wastewater Alliance, Pierce County Utilities, Lakehaven Utility District, King County and others. For example, the Sammamish Valley Reclaimed Water Facility proposed by the King County Department of Natural Resources would use reclaimed water to irrigate farms and open space recreational areas, replacing existing freshwater diversions from the Sammamish River.

    More information

    The Department of Ecology provides information and technical assistance to help planning groups, users, utilities and consultants assess and implement opportunities for reclaimed water. Contact Ecology’s Water Quality Program in the regional office serving the planned project.

    Ecology’s Web site ( provides standards and engineering design criteria, information on existing and planned projects, guidance documents to aid planning processes and links to other resources.

    New additions to the Web site include two important reports from recent Ecology workshops: Reclaimed Water Facility Operators Workshop (03-10-054) and Water Reuse Planning for the State of Washington (03-10-061). Standards, manuals and reports can also be ordered through Ecology’s publications office, (360) 407-7472.

    Kathy Cupps is a professional engineer registered in the state of Washington. She is employed as the statewide policy and engineering lead for reclaimed water at the Department of Ecology.

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