Lower Yakima Valley Groundwater Management Area

We're partnering in a local effort to reduce nitrate concentrations in Lower Yakima Valley private drinking water wells.

En Español

The Lower Yakima Valley Groundwater Management Area (GWMA) is a community-based effort working to reduce nitrate concentrations where many citizens rely on groundwater as their drinking water source. Studies and work to produce a comprehensive groundwater management program are nearly complete.

The goal of the program  is to address all sources of nitrate, and implement strategies to improve groundwater quality to meet drinking water standards in these wells.


Draft lower Yakima valley groundwater management program

On Dec. 13, 2018, the Groundwater Advisory committee voted to move a draft groundwater management program forward for the State Environmental Policy Act (SEPA) review and to the public for review and comment. The comment period is Feb. 25  to March 27, 2019, with a public hearing on March 12, 2019 at the Sunnyside Community Center. 

How to provide comments

We will accept comments from Feb. 25, 2019 to March 27, 2019.

Online (preferred):  Submit your comments through our online comments form.  

By mail:  David Bowen
WA State Department of Ecology
1250 West Alder Street
Union Gap, WA  98903-0009

In person:  You may provide oral or written comments during our public hearing (see details below).

Public Hearing

We held a public hearing on the proposed draft at the Sunnyside Community Center on March 12, 2019. 

Draft documents:

Learn more

En Español

El Área de Manejo de Agua Subterránea del valle bajo de Yakima (GWMA) se formó en 2012 para abordar la meta de reducir la concentración de nitratos en el agua subterránea. El contenido del programa describe el problema de la elevación de los nitratos en el agua subterránea, cómo se estableció el programa GWMA en el valle bajo de Yakima y define las metas y objetivos desarrollados para el GWMA. Este informe explica los efectos ambientales y en la salud de los nitratos en el ambiente, describe los orígenes de nitrato, y las diferentes autoridades reguladoras que afectan el nitrato en el agua subterránea.

Solutions led by the community

In 2011, the Legislature authorized funding for Yakima County to establish the Lower Yakima Valley Groundwater Management Area in accordance with state law to develop strategies to reduce groundwater contamination in the Lower Yakima Valley. Initial studies showed 12 percent of private domestic wells had elevated concentrations of nitrate in the Lower Yakima Valley.

New 2017 sampling results

A 2017 sampling effort within GWMA boundaries tested more than 150 private domestic wells. Results found that 20 percent of the wells sampled consistently exceeded the drinking water standard for all samples collected (USGS, 2017). Samples were taken once every two months.

Learn more by checking out resources on the Yakima County Lower Yakima Valley Groundwater Management Area website.

Our role in Lower Yakima Valley GWMA

Along with administering the work plan and contract with Yakima County, we are highly involved in this project, providing research, data, technical, and outreach support for Groundwater Management Area activities in the Lower Yakima Valley.

Why it matters

Nitrates are a concern in the Lower Yakima Valley — especially in areas where many homes draw drinking water from shallow aquifers. Nitrate levels exceed state drinking water standards in some regions of the valley. In other areas, concentrations are high enough to show us the community needs to avoid introducing nitrogen to their groundwater system to protect the quality of their drinking water.

Nitrates can be a risk to your health

Drinking water high in nitrates poses a threat to children under age five, infants, pregnant mothers, and the elderly. It can lead to a serious condition that reduces oxygen to red blood cells, which if untreated, may cause death. This is commonly known as "blue baby syndrome" in infants.

How do nitrates get into the environment?

Agriculture is the primary economic and land use activity in the Lower Yakima Valley. Agriculture lands — such as irrigated row crops, orchards, large and small livestock, and dairy operations — can be a source of nitrate pollution if they are not managed properly

Studies show that fertilizer applications and current land-use activities are contributing to the nitrate-loading on lands and aquifers. The Lower Yakima Valley GWMA is working across the region to educate landowners and identify which best farming practices protect water quality. Learn more about our effort to develop best management practices (BMPs) for agriculture.

Lower Yakima Valley GWMA objectives

Led by Yakima County, a citizen advisory panel is guiding the development of a comprehensive groundwater management program to reduce nitrate contamination where concentrations do not meet drinking water standards. The panel is made up of concerned citizens, environmentalists, farmers, dairy producers, university, tribal, as well as local, state, and federal government agencies.

The Lower Yakima Valley Groundwater Advisory Committee and its various subcommittees are working to finalize a plan to address nitrate contamination.

As spelled out in state statute, the committee is made up of citizens, agricultural and environmental stakeholders, local health and public works officials, and representatives of the state departments of Ecology, Agriculture, and Health, and U.S. Environmental Protection Agency.