Proposed Updates to the Ontario Wetland Evaluation System

ERO number
Notice type
Posted by
Ministry of Natural Resources and Forestry
Notice stage
Proposal posted
Comment period
October 25, 2022 - November 24, 2022 (30 days) Closed
Last updated

This consultation was open from:

October 25, 2022
to November 24, 2022

Proposal summary

In support of Ontario’s Housing Supply Action Plan 3.0 and the government’s commitment to support the construction of 1.5 million new housing units over the next ten years, the province is proposing updates the Ontario Wetland Evaluation System that would remove duplicate requirements and streamline the evaluation process.

Proposal details

Everyone in Ontario should be able to find a home that is right for them. But too many people are struggling with the rising cost of living and with finding housing that meets their family’s needs.

Ontario’s housing supply crisis is a problem which has been decades in the making. It will take both short-term strategies and long-term commitment from all levels of government, the private sector, and not-for-profits to drive change. Each entity will have to do their part to be part of the solution to this crisis.

Ontario needs more housing, and we need it now. That’s why the Ontario government is taking bold and transformative action to get 1.5 million homes built over the next 10 years.

To support More Homes Built Faster: Ontario’s Housing Supply Action Plan 2022-23, the government introduced the More Homes Built Faster Act, 2022,which, if passed, would ensure that cities, towns, and rural communities grow with a mix of ownership and rental housing types that meet the needs of all Ontarians.

These changes are providing a solid foundation to address Ontario’s housing supply crisis over the long term and will be supplemented by continued action in the future.


Under Ontario’s current policy framework, an evaluated wetland is a wetland that has been assessed according to the Ontario Wetland Evaluation System (OWES). The OWES is the official procedure to:

  1. determine the wetlands that are significant
  2. determine the boundaries of significant wetlands

The OWES assesses wetlands under four categories: biological, social, hydrological and special features. OWES defines a significant wetland as any evaluated wetland that scores 600 or more points in total, or that scores 200 or more points in either the biological component or the special features component.

The OWES consists of two manuals: the Southern OWES (used to evaluate wetlands located in Ecoregions 6 and 7) and the Northern OWES (used to evaluate wetlands located in Ecoregions 2, 3, 4, and 5). Coastal wetlands are also evaluated using these OWES manuals.

The OWES has been in place since 1983. Over the last decade in particular, we have heard practitioners voice concerns and recommendations for improvements to how Ontario’s significant wetlands are assessed and identified.

Proposed changes

We are proposing the following changes to content in the OWES manuals:

  • add new guidance related to re-evaluation of wetlands and updates to mapping of evaluated wetland boundaries
  • make changes to better recognize the professional opinion of wetland evaluators and the role of local decision makers (e.g. municipalities)
  • other housekeeping edits to ensure consistency with the above changes throughout the manual

The attached document under Supporting Materials reproduces the current OWES southern manual (without graphics and formatting) and shows proposed changes in blue font. Where the OWES northern manual contains the same content, the proposed changes would be made in that manual as well. Sections of the OWES manuals that are not proposed to change at this time have not been included in the document.

Regulatory impact analysis

The anticipated impacts of the policy proposal on business are neutral to positive. The proposed changes are intended to:

  • provide greater certainty and clarity related to how significant wetlands are assessed and identified
  • allow for further streamlining of development decisions by removing the requirement for the ministry to review and confirm wetland evaluation results

Through this posting, we welcome comments on anticipated benefits or costs to better help the ministry understand the real costs or cost savings associated with these proposed changes.

Supporting materials

View materials in person

Some supporting materials may not be available online. If this is the case, you can request to view the materials in person.

Get in touch with the office listed below to find out if materials are available.

MNRF - PD - Resources Planning and Development Policy Branch

300 Water Street, 2nd Floor, South Tower
Peterborough, ON
K9J 8M5


Commenting is now closed.

The comment period was from October 25, 2022
to November 24, 2022

Connect with us


Public Input Coordinator

Email address
MNRF - PD - Resources Planning and Development Policy Branch

300 Water Street, 2nd Floor, South tower
Peterborough, ON
K9J 3C7

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