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  • Writer's pictureDayna Edwards

Ottawa Zoning By-law Amendment to Align the Zoning By-law with Bill 23

On October 11th Council approved recommendations to amend the Zoning By-law 2008-250 to permit up to two (2) additional units on fully-serviced residential lots.

In November 2022, The Province of Ontario adopted Bill 23, the “More Homes Built Faster Act”. A significant change introduced through this legislation is that a requirement to allow for up to three residential units, in the form of up to two additional units or a coach house and an additional unit, is now mandated Province-wide for all lands serviced by municipal services.

This revision to the Planning Act has triggered the need to modify the City’s Zoning By-law to ensure it is consistent with the amendments in Bill 23, to respond to critical issues of interpretation, to provide clarity for applicants and the general public.

A brief summary of the immediate changes include the following:

Creation of a new “additional dwelling units” section which will comprise both additional units within the principal building and additional units within coach houses;

• Elimination of maximum floor area limits for “additional units” within the principal building. Setback, size, and height provisions for coach houses are proposed to remain as-is; and

• Implementation of a maximum parking utilization ratio and minimum soft landscaped area for rear yards associated with low-rise residential development.

What is happening across the Province and Country?

Some municipalities across Ontario are looking to permit up to 4 units per lot in order to access the Federal Housing Accelerator Funding. On November 3, Sean Fraser, the Minister of Housing, Infrastructure, and Communities, announced that an agreement had been made to provide Kitchener with $42.4M to encourage homebuilding. The funds will fast-track the creation of 1,216 housing units over the next three years, and spur the construction of more than 37,500 homes over the next decade.

In addition to Kitchener, ​​ London, Vaughan, Hamilton, Brampton, and Halifax have reached Housing Accelerator Funding agreements to date.

Like in Ontario, the Government of British Columbia is making sweeping changes to enable more low-rise, multi-family residential developments. For lots currently zoned for single-family or duplex use, lots with an area size of smaller than 280 sq metres (3,014 sq ft) can achieve up to three units, while lots greater than 280 sq metres can achieve up to four units. For lots larger than 280 sq metres located in close proximity to public transit stops with frequent service, up to six units may be permitted.


A detailed summary of the City of Ottawa By-law amendments required to implement provisions for additional dwelling units as per Bill 23 are provided below:

Sections 133 (regarding secondary dwelling units) and Section 142 (regarding coach houses) will be merged into a single section relating to “additional dwelling units”, so that all scenarios respecting the additional units permitted via Bill 23 are addressed within a single section. This section will include the following:

• Permissions for up to two additional dwelling units (for a total of no more than three units) on a fully serviced residential lot containing a detached, semi-detached, duplex, or townhouse dwelling;

• Permissions for up to one additional dwelling unit on a residential lot without access to full municipal services. This is the same as is presently permitted in the Zoning By-law;

• Clarification that additional unit permissions apply to each principal unit of a semi-detached or townhouse dwelling, regardless of whether or not the principal units are severed for separate ownerships;

• Removal of maximum floor area limits on individual units within the principal building, where principal or secondary, whereas Section 133 currently requires any secondary unit not located entirely in the basement to be no more than 40% of the floor area of its principal dwelling unit;

• Retention of maximum limits on the number of bedrooms within a principal or additional dwelling unit in accordance with the definition of a “dwelling unit” in the Zoning By-law (i.e. 4 bedrooms), except in cases where “oversize” dwelling units are permitted. In no case is the total number of bedrooms across all units on a lot containing additional dwelling units permitted to exceed twelve;

• Clarification that the maximum number of principal plus additional dwelling units, where permitted, cannot exceed three (regardless of whether they are in the principal building or as a coach house), in accordance with Bill 23;

• Retention of the existing regulations on coach houses verbatim where possible, including restrictions on the size, height, and yard setback requirements of a building;

• Removal of prohibitions on separate entrances for additional units contained within the front wall of a building.

Additionally, it is necessary to amend other sections of the By-law where direct prohibitions on additional units exist to remove those prohibitions. In particular:

• Exceptions 1256-1262, which apply to the former Village of Rockcliffe Park, contain provisions prohibiting secondary dwelling units and coach houses. It is proposed to remove these prohibitions, as is required by Bill 23. All other elements of these exceptions will continue to apply, including requirements for maximum floor space index (FSI) which will apply to all coach houses in the same manner as they are applied to the principal building and accessory buildings. The definition of “gross floor area” specific to these exceptions is proposed to be amended in this regard, to clarify that it applies to both “accessory buildings” and “coach houses”.

• The requirement to permit up to three units on a residential lot is not intended to be extended to areas covered by the Flood Plain Overlay and governed by Section 58 of the Zoning By-law, given their increased flood risk. It is proposed to update the language in Section 58 to clarify that additional dwelling units partially or fully below grade are proposed to remain prohibited in the Flood Plain Overlay.

• Section 101 (Minimum Parking Space Rates) is proposed to be amended to eliminate requirements for additional parking in association with additional dwelling units in a duplex dwelling, as secondary/additional dwelling units do not require on-site parking in other scenarios in the By-law, and Bill 23 limits the extent to which on-site parking can be required for additional units.

As the amendment will replace the term “secondary dwelling unit” with “additional dwelling unit”, a new definition which will include both additional uses within the principal building and coach houses, technical amendments will also be required to replace all instances of the term “secondary dwelling unit” in the Zoning By-law with “additional dwelling unit”.

The amendment also includes items not specifically required to address Bill 23’s additional dwelling unit requirements, but ensures that zoning requirements are in place to manage potential impacts associated with multi-unit development, specifically rear yard landscaping and associated parking areas. These include the following:

A maximum of 70 percent of the rear yard area may be occupied by parking spaces, driveways, and aisles. This regulation places an upper limit on the amount of rear yard space that can be used for parking purposes, including access to all rear yard parking spaces on a lot.

At least 15 percent of the rear yard area must be softly landscaped. This regulation ensures that there is a minimum soft landscaping requirement set out for all uses in residential zones, including in instances where parking or other hard surfaces are provided in rear yards. This provision combined with the aforementioned 70 percent limit on rear yard parking areas also ensures some space is available to be left over for other functions, including rear entrances/landings into buildings, storage or waste/recycling sheds, or rear yard porches or decks.

Harmonizing Performance Standards Across Building-types

The report further notes that staff are mindful that the change to up to three residential units per parcel has significant impacts across the Zoning By-law, and calls into question the regulatory differences between detached, duplex, semi-detached, triplex and smaller low-rise building forms. Staff are further mindful that changes to the Development Charges Act may be a significant incentive towards “Bill-23”-enabled development, and away from purpose built “missing-middle” development forms such as triplexes, fourplexes, sixplexes and low-rise apartments.

It is anticipated that harmonizing performance standards across building typologies such as detached, duplexes, semi-detached and triplex will proceed as part of the Comprehensive Update of the Zoning By-law currently underway and planned for approval in 2025.

Source: Zoning By-law Amendment - Aligning Zoning By-law 2008-250 with Bill 23 concerning Additional Dwelling Units, Report to Planning Committee and Council, October 11th, 2023, Robert Sandercott

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