Flood risk, floodplains and conservation authority rules
Doorvia Guides · June 5, 2026
If a property sits in a regulated area, building, grading and even a deck can require a conservation authority permit.
Ontario's conservation authorities regulate development near watercourses, wetlands, valley slopes and shorelines. If a property falls within a regulated area, adding a deck, pool, addition or fill can require a permit, and some work will not be approved at all.
Flooding also affects insurance. Overland flood and sewer backup coverage is not automatic, and in higher-risk areas it can be limited or expensive.
Before you waive conditions, check the local conservation authority mapping, ask the municipality about the property's zoning and any fill or grading permits, and get an insurance quote that specifically confirms water coverage.
More from the newsroom
Market update
GTA market update: what buyers are seeing this fall
Listing counts are up across the Greater Toronto Area while price growth stays flat, giving buyers more room to negotiate.
Buying guide
Ontario land transfer tax: the rates and how the bill is calculated
Ontario land transfer tax is charged in brackets, so the rate rises only on the portion of the price above each threshold.
Pre-construction
The 10-day cooling-off period on a new Ontario condo
Buyers of a new condominium from the developer get a statutory 10-day right to rescind without penalty.