Ground water surfaces near Snipes Mountain, Lower Yakima Valley, Washington State, September 2009.  Photo provided by Ryan Anderson, WA Department of Ecology.
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Lower Yakima Valley Groundwater Quality

Background

Many people in the Lower Yakima Valley depend on ground water as a drinking water source. Past study results show that 12% of the valley’s wells that have been tested do not meet drinking water quality standards for a chemical called nitrate. About 20% have elevated levels of nitrates, and many are above the background level for the area. Increased awareness of groundwater contamination in private drinking water wells prompted the Washington State Department of Ecology (Ecology) to work with the U.S. Environmental Protection Agency (EPA), Washington State Department of Agriculture (WSDA), Washington Department of Health (WDOH), and Yakima County to address the many challenges associated with regional groundwater contamination.

Why this matters

Nitrate reduces the ability of red blood cells to carry oxygen. Infants under six months of age, pregnant women, individuals whose bodies are unable to break down methemoglobin to hemoglobin efficiently, and those with low levels of stomach acid are at risk if their drinking water supply exceeds the nitrate drinking water standard of 10 mg/l nitrate-nitrogen. Infants who drink water with high levels of nitrate (or eat foods made with nitrate-contaminated water) may develop a serious health condition, called methemoglobinemia or “blue baby syndrome”, due to the lack of oxygen.

Status of the project

Ecology, EPA, WSDA, WDOH, and Yakima County completed a report titled “Lower Yakima Valley Groundwater Quality - Preliminary Assessment and Recommendations Document”. The report describes the various problems identified by community members, agriculture, health, and environmental professionals associated with the groundwater pollution and:

Technical information

Quality of Ground Water in Private Wells in the Lower Yakima Valley, 2001-02 (Ecology publication)

Lower Yakima Valley Groundwater Quality: Preliminary Assessment (Ecology publication)

Request for Identification: Lower Yakima Valley Groundwater Management Area (Pacific Groundwater Group publication)

Administrative Order Activating the Lower Yakima Valley Groundwater Management Area

Related information

Ecology’s Groundwater Quality

WDOH Drinking Water Program

Tractor applying inorganic nitrogen to a field in Eastern Washington. Photo provided by Ryan Anderson, WA Department of Ecology. Child drinking water. Photo provided by Ryan Anderson, WA Department of Ecology. Liquid manure being sprayed on cropland in the Lower Yakima Valley, Washington State, September 2009. Photo provided by Ryan Anderson, WA Department of Ecology.

Important Information for Private Well Owners (WDOH Publication)

EPA Office of Drinking Water

Yakima County Health Department Drinking Water Page

EPA and Yakima Valley dairies consent decree (March 19, 2013) (PDF)

EPA’s Lower Yakima Valley groundwater website

For more information

Yakima County logo. WA State Department of Ecology logo. U.S. Environmental Protection Agency logo. WA State Department of Agriculture logo. WA State Department of Health logo.
David Bowen
Water Quality Program - Central Regional Office
Washington State Department of Ecology
Phone: (509) 457-7107
E-mail: David.Bowen@ecy.wa.gov

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Last updated June 2016