EPA Region 10 has reached agreement with four central Washington dairies to address high levels of nitrate in the underground source of drinking water beneath and downgradient of the dairies. Monitoring well sampling by EPA shows nitrate in area groundwater as high as 190 mg/L (the MCL is 10 mg/L). The dairies animal waste handling practices contribute to the elevated levels of nitrate in the groundwater. The dairies have agreed to provide alternative water supply to affected residents within one mile downgradient of the dairies, implement source control actions, install monitoring wells and conduct quarterly monitoring for eight years to evaluate progress in reducing nitrate levels in the drinking water aquifer.