DRINKING WATER SURVEILLANCE PROGRAM (DWSP)

What is DWSP?

Ontario’s Drinking Water Surveillance Program (DWSP) is a science-based monitoring program which looks at drinking water quality with a particular focus on non-regulated drinking water quality parameters and emerging contaminants. Developed by the Ministry of the Environment (MOE) in 1986, DWSP is a voluntary program operated in cooperation with participating municipalities.

Which Drinking Water Systems are Monitored by DWSP?

Starting with 22 municipal drinking water systems that were located in southern Ontario, the program now has over 100 systems spread across most of the province.  A map of the DWSP monitoring network shows the participating drinking water systems.

Is DWSP Monitoring Different from Regulatory Monitoring?

DWSP is different from the ministry’s audit inspections program and the compliance monitoring that is carried out by drinking water systems.  The emphasis of DWSP is on collecting data for scientific purposes and investigating new issues in drinking water. DWSP collects drinking water samples that are in addition to the minimum requirements of the Drinking Water Systems Regulation O. Reg. 170/03.

Although the focus of DWSP is on non-regulated water quality parameters, data from some regulated parameters are also generated by the comprehensive analytical methods that are used.

DWSP does not collect samples for microbiological parameters such as Escherichia coli (E. coli).  Instead, microbiological monitoring is conducted by every drinking water system under O. Reg. 170/03.

The Drinking Water Surveillance Program contributes to the Ministry of the Environment’s goal of ensuring safe, clean drinking water for the people of Ontario.

DWSP monitors municipal drinking water from source (left) to tap (far right).  Plant operators collect raw water samples where the water enters water treatment plants (middle) in order to assess the quality of the source water.  Treated drinking water and water from the distribution systems are sampled to ensure the drinking water is safe.