When do I need a Conservation Authority permit in Ontario to build?

In Ontario, Conservation Authorities regulate development in areas that affect or are affected by natural hazards — primarily floodplains, wetlands, shorelines, and steep or unstable slopes. Before building, grading, filling, or placing structures in or near these areas, you may need a permit under the Conservation Authorities Act.

Each Conservation Authority has its own regulated area, and the boundaries are mapped. If any part of your property falls within the regulated area, you must apply to the relevant Conservation Authority (for example, the Credit Valley Conservation, TRCA, or NVCA depending on your watershed) before beginning construction or site alteration. Working without a permit in a regulated area can result in stop-work orders, fines, and orders to restore the site.

Permits are assessed based on potential risk to flood control, erosion control, and natural features. They are separate from, and in addition to, municipal building permits; you typically need both. Conservation Authority permits can impose conditions on how, where, and when you build — for example, setbacks from the edge of the regulated area or limits on impervious surface coverage.

If you are buying rural or waterfront property, a due diligence review should always include checking whether the land falls within a regulated area, as it may affect your ability to develop it as intended.