Lower Yakima Valley Groundwater Management Area
We're working with local and state partners to reduce nitrate contamination in groundwater in the Lower Yakima Valley. Many people in this area use groundwater wells for drinking and cooking at home.
This community-wide project aims to reduce sources of nitrates, improve the aquifer so it meets drinking water standards, and educate residents about the problem and how they can protect themselves. We are using a long-term, holistic approach to address this issue because nitrates come from many sources.
We provide ongoing technical assistance, well monitoring, and education and outreach support to our partner agencies in the groundwater management group. More information is available on the Yakima County website.
What's happening now?
We are working with state and local agencies to address the problem, including implementing 64 recommended actions developed by an advisory committee.
We are currently monitoring nitrate levels in 170 wells throughout the area. Our data tell us how nitrate levels change across the area and how results may depend on seasonal variability or the conditions of a particular well. This helps us evaluate the success of our efforts to reduce nitrate pollution.
What is the GWMA?
The Lower Yakima Valley Groundwater Management Area (GWMA) is the area where we are working to reduce nitrate contamination in groundwater. The GWMA covers much of the Lower Yakima Valley watershed. Its designation helps focus resources on an area that provides drinking water for about 56,000 people.
Why are nitrates a concern?
Nitrate is a chemical that can come from human waste, animal waste, fertilizer, commercial activities, and even natural sources. It is the most common groundwater contaminant and can easily move through soil with rain or irrigation.
Our data estimates that 21% of wells in the Lower Yakima Valley may have elevated levels of nitrate. This can pose health risks to vulnerable populations like infants, pregnant people, and people with certain health conditions.
Working together for clean drinking water
We are working with county, local health, state, federal, and agricultural partners. These groups participate in a committee tasked with implementing the approved plan to reduce nitrate concentrations. Learn more in the program documents section below.
Our staff continue to lend support through community outreach, research, data collection, and technical expertise to make this effort a success.
Many agencies and organizations are working to help people safely use groundwater in the Lower Yakima Valley.
- Yakima Health District is delivering free bottled water to people whose wells have high nitrate levels. It is also offering well testing resources like nitrate test strips and is working on community focus groups.
Contact: Shawn Magee or Jocelyn Castillo
- Yakima County led planning efforts and continues supporting outreach and implementation.
Contact: Lisa Freund
- Washington State Department of Health is funding the free bottled water delivered by the Yakima Health District. It completed an assessment of health risks from nitrate contamination in the Lower Yakima Valley. The agency also provides wellhead protection guidance.
- Contact: Holly Myers or Sheryl Howe
- South Yakima Conservation District coordinates implementation of the work plan and recommended actions developed by the advisory committee. The agency provides deep soil sampling and agricultural technical assistance for reducing nitrate levels.
Contact: Rodney Heit
- Washington State Department of Agriculture studied sources of nitrate in the Lower Yakima Valley. The agency continues to provide agricultural technical assistance.
Contact: Gary Bahr