Tackling nitrate contamination

Groundwater monitoring in the Lower Yakima Valley to reduce risks

Among our top priorities in Governor Jay Inslee’s 2020 supplemental budget is a request for $378,000 to expand monitoring for nitrates in Lower Yakima Valley private drinking water wells relied upon by as many as 56,000 residents there.

Over the years, we've lent support to provide research, data, and technical expertise to the community-based Lower Yakima Valley Groundwater Management Area (GWMA) committee's work to tackle and reduce sources of nitrates in drinking water.
Our staff participated with the local groundwater advisory committee to develop recommendations to address all sources of nitrate, and implement strategies to improve groundwater quality to meet drinking water standards. We conducted a sampling and monitoring regimen to evaluate progress during the GWMA process.
With this request, we are seeking additional funds to build on that data within the GWMA boundaries. We've licensed hydrogeologists with the knowledge and skills to conduct this type of study to assure credible data is collected, and the program is science based.
The new budget request calls for 2.9 FTEs (fulltime equivalent employees) for groundwater monitoring of 170 groundwater wells to help to establish baseline conditions and measure how management practices affect groundwater quality.

Why is Ecology sampling wells?

The Yakima River Basin is a complex watershed where legacy and current land use activities influence groundwater quality. These activities include irrigated agriculture, dairy operations, on-site sewage systems, commercial operations, and hobby farms.

A recent groundwater study of 150 private domestic wells in the Lower Yakima Valley found that 20 percent of wells consistently exceeded the drinking water standard for all samples collected. The 2017 study also showed that 26 percent of the wells had at least one in six samples exceeding the drinking water standard. Nitrate consumption can lead to health risks for infants, pregnant women and the elderly.

Why are private wells more vulnerable to contamination?

Unlike public drinking water systems, private domestic wells are not regulated to assure drinking water meets standards. Individual private well owners are encouraged by the state Department of Health to sample their wells annually for bacteria and nitrate. Well owners also can learn about healthy practices to protect their well water on Yakima County’s GWMA website.

Still, we need to address the larger problem of elevated nitrate concentrations in groundwater, which is the predominant drinking water source in the Lower Yakima Valley.

What does GWMA Program do?

The Lower Yakima Valley GWMA Program identifies best management practices to reduce nitrate pollution associated with various land uses. Providing educational information and specific implementation opportunities for homeowners, residents and agricultural operators are key components for protecting water quality.

Our Environmental Assessment Program’s expertise in monitoring is a natural fit to work in tandem with these broader GWMA goals. We are redoubling our commitment with this monitoring request.

Bottom line

We see an opportunity for success in the Lower Yakima Valley GWMA where local recommendations identify actions for all parties to take to protect drinking water and prevent nitrate pollution.

A map showing the boundary of the Lower Yakima Valley Groundwater Management Area, Yakama Nation boundary to left, GWMA to the right.
We pledge to support the local governments (Yakima County, Yakima Health District, South Yakima Conservation District) and stakeholders as they move the GWMA plan forward, and urge them to follow through on the commitment they made to lead the effort to find local solutions for groundwater pollution in their communities.

Learn more about these bills and others

We’re committed to keeping people informed on our legislative actions. You can learn more about these bills and other legislative priorities by visiting our 2020 Legislative Priorities web page. Updates on bill status will also be shared on our Twitter account @EcologyWA

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