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What is a flood plain overlay?
Flood plain lines are drawn by Ontario's conservation authorities. Where a municipality carries those lines into its zoning by-law, they become an overlay that limits what can be built on the lots inside it. Ottawa's Zoning By-law 2026-50 does this, and that overlay is the record this check reads.
Report check: Flood plain overlay. Entry reviewed 20 Oct 2026; each source below shows its own data date.
How a report shows itsample, made-up home
The City's zoning map doesn't show the lot in the flood plain.
- Overlay
- Not inside
- Nearest mapped flood plain
- 180 m north, along Sample Creek
Where we read it
- Toronto
- Ottawa
- Hamilton
- Guelph
- Other Ontario
the town's own records– not in our reports there yet
Published byCity of Ottawa
Conservation authorities from 1 February 2027
Under the Conservation Authorities Act as amended in 2026, today's authorities are to join regional ones on 1 February 2027 or a later date set by regulation, as each town's flood page says. Each box shows the authorities our town pages name and the towns whose pages name it; a town with land under two authorities is in both.
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- Central Lake Ontario authority
- Toronto and Region authority
joinCentral Lake OntarioRegional Conservation Authority
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- Conservation Halton
- Credit Valley authority
- Hamilton authority
- Niagara Peninsula authority
joinWestern Lake OntarioRegional Conservation Authority
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- Grey Sauble authority
- Lake Simcoe Region authority
- Nottawasaga Valley authority
joinLake HuronRegional Conservation Authority
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- Catfish Creek authority
- Grand River authority
- Kettle Creek authority
- Long Point Region authority
joinEastern Lake ErieRegional Conservation Authority
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- Cataraqui Conservation
- Ganaraska Region authority
- Kawartha Conservation
- Lower Trent Conservation
- Otonabee Conservation
- Quinte Conservation
joinEastern Lake OntarioRegional Conservation Authority
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- Essex Region authority
- Lower Thames Valley authority
- Upper Thames River authority
joinWestern Lake ErieRegional Conservation Authority
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- Conservation Sudbury
- Mattagami Region authority
- North Bay-Mattawa authority
joinNortheastern OntarioRegional Conservation Authority
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- Lakehead Region authority
becomesNorthwestern OntarioRegional Conservation Authority
What the record is
A flood plain is the land a river or creek spreads over in a large flood. In Ontario the mapping is done by the local conservation authority for the regulatory flood (in most of the province the 1-in-100-year flood, in some watersheds a larger historic storm). A municipality can adopt those lines into its zoning by-law as an overlay, which then sets what the by-law permits on the lots inside it: Ottawa's overlay, in Section 58 of By-law 2026-50, is one example.
The report line says whether the lot is inside the overlay and, when it isn't, how far the nearest mapped flood plain is. Outside Ottawa, the conservation authority's own flood map is the record to read: most authorities don't license their maps for reuse in reports like ours, so the line points to the authority for the address instead.
Where it runs
What the report reads for this check depends on what each municipality publishes.
What we read in each town5 towns, each with its source and date
| City | What the report reads |
|---|---|
| Toronto, Hamilton, Guelph and Other Ontario | Not in our reports here yet. Flood plain maps are made by the local conservation authority, and most don't allow their maps in reports like this one. The conservation authority for this address can say whether the lot is in a flood plain; many have an online map. Conservation Ontario: find a conservation authority |
| Ottawa |
Sources
Contains information licensed under the Open Government Licence – City of Ottawa.
Check one address
This check answers the dealbreaker “Flood plain” on the order form. It is in the full report, with the other 54 checks, for any Ontario home.
Public-record information, not legal, financial, insurance or inspection advice. Records change and can be incomplete, and this page describes the records, not any particular home. Spotted an error, or have a question about this record? Email [email protected]; we answer from the record, and corrections are listed on the guide index. What we cover, city by city.