The District of Columbia Department of Health (DC-DOH) monitors the water quality of the mainstem of the Potomac River from Rosier Bluff to Key Bridge. Monitoring is conducted bimonthly. The data are sent to COG on an annual basis and the Chesapeake Bay program also collects this information - visit the CIMS web site for more information.

Parameters collected include: Temp, DO, series of metals, nutrients, bacteria, Secchi, Specific Condu, Salinity and pH, depending on  the station