Partnering on safe well water in the Lower Yakima Valley

Graphic showing map of Yakima Valley and photo of two people taking samples in a field
Safe drinking water is of particular interest in the Lower Yakima Valley, where much of the population relies on private wells for water. Recently, an independent advocacy group shared with us a study identifying several chemicals in groundwater that caught our attention.

In all, seven private drinking water wells scattered along the Interstate 82 corridor between Toppenish and Prosser showed higher levels of some chemicals, including three wells near the Yakima River that tested positive for dioxins.

Although concentrations of dioxins are typically low in water, they and other chemicals can pose health risks to people.

In light of this information, our Environmental Assessment Program is teaming with Yakima County Health District to evaluate well water in the area of concern.

“We think it’s important to work with the community and investigate the potential contamination in these wells,” said Sage Park, Ecology’s Central Region director. “Over the next week we will be reaching out to people in the study area and encouraging them to participate in this well-testing effort. Taking water samples is the best way for us to provide people with the information they need to assure their drinking water is safe."

Free sampling begins this fall

Beginning Nov. 4, we will sample groundwater for the presence of dioxins, nitrate, lead and arsenic from 15 wells in the study area. We plan to sample again next spring and fall to account for seasonal variations and to assure we obtain a good data set over several seasons.

Once sampling is complete, we will share results with well owners and explain what they mean. If testing indicates there are harmful chemicals in any of the wells, residents in the immediate area may consult with Yakima Health District for advice and may be advised to rely on alternate drinking water resources.

You can learn about the health effects of contaminants in drinking water and testing recommendations by visiting the Washington Department of Health and Environmental Protection Agency websites.

For more information on the study, residents may contact our Central Regional Office at 509-575-2490.