Water Quality

In support of the Oregon Department of Environmental Quality mission statement of restoring and protecting Oregon's water, air and land, the Water Quality Monitoring program is currently involved in the following activities:

  • Collecting representative, valid environmental data through physical, chemical, and biological sampling and assessment.

  • Managing environmental data to ensure availability of accurate and complete data from agency programs and the general public.

  • Analyzing and interpreting water quality related data to produce reports which identify water quality conditions, identify threats to water quality, evaluate trends, and model proposed actions.

Ambient Water Quality Monitoring Network 

The Oregon Department of Environmental Quality is responsible for keeping Oregon’s surface waters safe and healthy for a variety of uses such as drinking water, recreation, fish habitat and irrigation. To monitor status trends in water quality, DEQ regularly collects water samples at over 130 sites on more than 50 rivers and streams across the state. Sites were chosen to represent important positions within each basin, acting as integrator sites to represent major land uses.
Sites are visited every other month throughout the year. Water quality parameters that are measured include alkalinity, biochemical oxygen demand, chlorophyll a, specific conductance, dissolved oxygen, DO percent saturation , e. coli, ammonia, nitrate & nitrite, pH, pheophytin a, dissolved ortho-phosphate, total phosphate, total solids, temperature and turbidity.
Some sites have been routinely monitored since the late 1940's. Ambient monitoring is used to understand trends in Oregon's water quality over time, determine whether there is too much pollution in a water body, and set limits of how much pollution a water body can safely receive. Ambient monitoring data is also used to determine the Oregon Water Quality Index.