Great Lakes Water Resource Managers' Initiative Resouce Kit


OntarioWater Management Program Information:
Ontario's water management is performed by the Ministry of the Environment, which may be accessed at:

Agreement Enacting Legislation:
Ontario's legislation enacting the Agreement may be accessed at:

Impact and Impact Assessment:
Impact assessments are required for some projects through the Environmental Assessment Act. Under the Act more complex projects require a full individual environmental assessment. For others, Class Environmental Assessments are approved subject to compliance with an approved class environmental assessment process (e.g. Municipal Engineers Association Class EA for Municipal Infrastructure projects, including water and wastewater projects).

Also, under the Ontario Water Resources Act, a permit to take water is required for any new or increased withdrawal of water over 50,000 litres per day from any water source in the Province. In issuing a permit to take water the following factors are considered:

  • Natural ecosystem functions – e.g. potential impact of the taking on minimum stream flows, natural water level/flow variations, habitat that depends on levels/flows and interrelationships between groundwater and surface water.
  • Water availability – e.g. impact on water balance and sustainable aquifer yield, existing water uses, low water conditions, whether the taking is in a high use or medium use watershed (certain highly consumptive water uses are restricted in these watersheds), any planned municipal use approved under the Environmental Assessment Act or under a Municipal Official Plan.
  • Issues related to the use of water – e.g. whether water conservation is implemented in accordance with best water management standards for the relevant sector, the purpose for the water use and other issues.

Water Taking Classification
To assist in the evaluation of proposed water takings under the Permit to Take Water Program, applications are classified based on their potential risk to the environment or potential to interfere with other water users.

  • Category 1 takings have a lower risk of adverse environmental impacts or interference (e.g. permit renewals, ponds not connected to or receiving water from surface water, takings from a Great Lake or connecting channel less than 1 million litres/ day) (unlikely to pose adverse environmental impacts).
  • Category 2 takings require a scoped assessment.
  • Category 3 takings require a detailed ecological/hydrological/hydrogeological study.

Water Budget Studies
Under the Clean Water Act, the Ministry of the Environment has partnered with Conservation Ontario, Conservation Authorities and the Ministry of Natural Resources to implement Ontario’s Source Water Protection program and develop source water protection plans. The Ministry of Natural Resources is leading the development of water budgets to estimate surface and groundwater supplies, water use demand and water quantity risk assessments in support of the plans. The water budgets will contribute to the cumulative assessment of water takings at a quaternary watershed scale.