Toronto and Region Conservation Authority (TRCA) monitors the quantity and quality of groundwater at various wells across the Region.

TRCA groundwater monitoring

What Do We Monitor And Why?

The Provincial Groundwater Monitoring Network (PGMN) was established in April 2000 to assess current groundwater conditions and provide an early warning system for changes in water levels and water quality. PGMN is a partnership program between the Ontario Ministry of the Environment, Conservation and Parks and the province’s conservation authorities, as well as some municipalities in areas not covered by a conservation authority. There are almost 400 wells monitored across the province.

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The role of the Ministry in the network is to set policy direction, develop strategic objectives and maintain the Provincial Groundwater Monitoring Information System database. TRCA is responsible for maintaining the digital telemetry systems at 19 groundwater monitoring wells in our jurisdiction, collecting water level data and arranging for chemical analyses of water quality samples at dedicated wells.

Of the 21 wells that were monitored for water level data in 2018, a total of 15 groundwater wells were also sampled for water quality. TRCA also intends to expand the network through partnerships with the regional municipalities of Durham, Peel and York. The Province is currently exploring options to convert to a satellite telemetry system over the next few years.

TRCA groundwater monitoring

What Are The Data Telling Us?

Approximately three million residents in Ontario rely on groundwater from municipal and private wells as their primary source of drinking water. Many communities are dependent on groundwater supplies to maintain existing domestic, commercial, industrial, agricultural and institutional operations. Overdrawing and contamination activities are elevating the stress placed on this vital resource.

In the most recent Toronto and Region Watersheds Report Card, approximately 60% of the groundwater monitoring wells in the TRCA jurisdiction received an ‘A’ grade for chloride. Overall, concentrations of nitrate were better than the drinking water guidelines in most wells across the jurisdiction.


Jeff Vandenberg
Environmental Technologist, Aquatic Monitoring and Management
Watershed Planning and Ecosystem Science