Ontario adds new environmental assessment requirements for water, sewage, stormwater, shoreline and road projects, effective January 2027

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

Starting January 1, 2027, a new regulation (O. Reg. 257/26) significantly expands the types of projects that must go through Ontario's environmental assessment process. Municipalities, water and wastewater public corporations, and some private developers will need to comply with Part II.4 environmental assessment requirements when establishing or making major changes to drinking water systems and treatment plants, sewage systems and treatment plants, sewage lagoon facilities, storm water management works, and shoreline or in-water works. Road-related activities by municipalities — including constructing more than one lane kilometre of road, building water crossings, constructing parking lots over 5,575 square metres, and building grade separations — are also newly designated as projects requiring assessment. Several new definitions are introduced (dam, watercourse, water crossing, sewage system types, storm water, private sector developer, and others) to clarify exactly what falls under these rules. Organizations planning any of these types of projects should review whether their specific activities meet the designation thresholds and, if so, begin factoring environmental assessment obligations into their project timelines well before the 2027 start date.

Who this affects: municipalities · water and wastewater public corporations · private sector land developers · owners and operators of drinking water and sewage systems · road and infrastructure project proponents