Ontario stormwater registry rules updated to cover spill containment works and underdrain systems at power generation sites

Plain-language summary · AI-assisted · not legal advice

A set of amendments scheduled to take effect September 1, 2026 expand Ontario's self-registration framework for stormwater management works to formally recognize two new types of works: spill containment works (designed to prevent pollutant discharges or keep pollutants out of incompatible drainage systems) and underdrain systems (underground works that move stormwater and groundwater to a discharge point for safety). Operators of these works at sites running electric power generation activities under NAICS code 2211 are exempt from certain site assessment, design and monitoring-plan requirements that apply to conventional stormwater works. Spill containment works must now meet specific volumetric design standards depending on whether they service equipment containing oil or storage tanks, and must include a mandatory monitoring plan with defined parameters, effluent objectives and minimum monitoring frequencies. The Operation and Maintenance Manual must now include a spill contingency plan for spill containment works, covering prevention procedures, spill identification, clean-up equipment readiness and a schematic of all connected works; staff who operate these works must be trained in spill response. Several procedural changes also apply across all stormwater works registrations, including revised wording on as-built drawing requirements, updated spill contingency plan obligations, and a grace period exempting registrants from updating their SWM reports solely because of changes introduced by these amendments.

Who this affects: operators of stormwater management works registered under the Environmental Activity and Sector Registry · electric power generation facility operators (NAICS 2211) · licensed engineering practitioners preparing SWM reports · owners of spill containment works or underdrain systems · environmental compliance leads at industrial sites