The Provincial (Stream) Water Quality Monitoring Network (PWQMN) measures water quality in rivers and streams across Ontario.Over 400 locations are currently monitored in partnership with Ontario's Conservation Authorities, participating municipalities and provincial parks.Partners collect water samples on an approximately monthly basis and deliver them to the Ministry's laboratory where they are analyzed for a suite of water quality indicators. The program has been operating since 1964 providing a valuable database for tracking changes in water quality over time. More recently, special studies have been implemented in agricultural and urban watersheds to collect additional information in support of source protection planning and nutrient, road salts and pesticides management.