Welcome to City of Yakima Regional Wastewater Treatment Plant Laboratory (lab). In accordance with the Environmental Protection Agency (EPA) and the Washington State Department Of Ecology (Ecology), our lab strives to ensure that all discharges to, and from, the WWTP meet all Federal and State standards as outlined in our National Pollutant Discharge Elimination System (NPDES) permit . As a Certified Laboratory, it is our responsibility to produce the most accurate and reliable data possible while monitoring the effectiveness of the WWTP, ensuring compliance with the City’s Sewer Use Ordinance, and protecting our water and environment in a cost-effective manner.

The primary function of the lab is to ensure that plant operations and discharges stay within acceptable parameters of our NPDES permit. Therefore, a number of samples from the WWTP influent, effluent, and biosolids are analyzed for pH, BOD, TSS, trace metals and nutrients on a daily basis. Pre-treatment samples collected from businesses and industries are also analyzed for the constituents mentioned above, as well as fats, oils, and grease (FOG).