Is an Oshawa address in a regulated flood area, and whose map says so?
The Central Lake Ontario Conservation Authority's regulation area mapping, updated in November 2025, and its floodplain mapping application, under Ontario Regulation 41/24.
Sources checked October 28, 2026
Conservation authorities in 2027
Central Lake Ontario authorityjoinsCentral Lake Ontario Regional Conservation Authority
On 1 February 2027 or a later date set by regulation, under the Conservation Authorities Act as amended in 2026.
- The recordFlood plain and regulated area
- Where to read itCLOCA regulation area mapping; CLOCA inquiries and permits and 5 more
- In the full reportWith the address's other records
What the record shows
The Central Lake Ontario Conservation Authority counts the City of Oshawa among its municipal partners; its watershed runs from Lake Ontario north to the crest of the Oak Ridges Moraine. Its regulation area mapping, endorsed by its board in November 2025, shows hazardous lands such as valleylands, wetlands, watercourses, flood and erosion areas and the Lake Ontario shoreline on 28 sheets, and it publishes an interactive floodplain map for property owners. The authority says new or enlarged structures, additional dwelling units, fill and grading near a stream or wetland may need its permit, and its staff confirm whether one is needed.
The City's accessory apartment rules also lean on this record: no apartment is permitted in hazard lands, or in areas without the access the authority requires, as identified by the authority. A regulated-area result governs permits for work near water; it is not a forecast that a home will flood, and a home outside the mapped area can still take water through a basement. Under the Conservation Authorities Act as amended in 2026, the Central Lake Ontario authority is to join the Central Lake Ontario Regional Conservation Authority on 1 February 2027 or a later date set by regulation.
Where to read it yourself
- CLOCA regulation area mapping: the authority's regulated area map sheets, updated November 2025
- CLOCA inquiries and permits: what may need a permit, and how to ask staff
- CLOCA flood protection and prevention: the authority's floodplain mapping application
- About CLOCA: the watershed and the authority's municipal partners
- Ontario Regulation 41/24: the regulation behind every conservation authority's regulated area
- Bill 97, Plan to Protect Ontario Act (Budget Measures), 2026: Schedule 3 amends the Conservation Authorities Act; the transition date is 1 February 2027 or a later date set by regulation
- Regional conservation authority boundaries (ERO 025-1257): the Province's decision of 10 March 2026 on which authority joins which of the nine regional authorities
What OfferDue covers in Oshawa
Conservation-authority regulated-area and flood plain checks are not currently included in our reports, so for an Oshawa home the authority's own mapping is the place to look. The full report's water and flooding group does cover past floods seen by satellite, nearby creeks, rivers and ponds, and mapped wetlands for any Oshawa address.
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. What we cover, city by city.