Garden Suite Zoning Rules by GTA City

The following table compares key dimensional and regulatory requirements for garden suites across nine GTA municipalities. These standards represent current bylaws as of 2026, though municipalities continue to refine regulations based on application experience. Note that additional site-specific requirements may apply based on lot dimensions, heritage designations, and overlay zones.

Each GTA municipality has implemented garden suite regulations with unique provisions reflecting local planning priorities, existing neighbourhood character, and infrastructure capacity. The following subsections provide detailed bylaw references and practical considerations for each jurisdiction.

Mississauga permits garden suites through Zoning By-law 0225-2007, Section 5.1.14, with amendments adopted in 2020 and refined through 2025. Garden suites are permitted as-of-right in detached and semi-detached residential zones where lot width exceeds 15 metres. The maximum gross floor area is 100 square metres (1,076 sq ft), with a maximum building height of 6.5 metres allowing for two-storey construction. Minimum setbacks require 0.6 metres from rear and interior side lot lines.

The principal dwelling must maintain one parking space, and the garden suite may not include basement space in floor area calculations. Lot coverage for both structures combined cannot exceed 40% of the lot area. Garden suites must be located behind the main dwelling's rear wall and cannot be converted to separate ownership. The City requires building permit applications to include servicing plans showing connections to municipal water and sanitary sewer systems.

Heritage-designated properties require additional Heritage Permit approval under Section 42 of the Ontario Heritage Act.

Brampton's garden suite provisions are contained in Zoning By-law 270-2004, amended by By-law 73-2021 effective May 2021, with technical updates through 2025. Garden suites are permitted in R1, R2, and R3 residential zones where the lot has minimum frontage of 15 metres and minimum area of 450 square metres. The maximum building size is 90 square metres (969 sq ft) with a 6-metre height limit restricting most garden suites to single-storey construction with loft spaces.

Required setbacks are 0.6 metres from the rear property line and 1.2 metres from interior side lot lines, with increased 1.8-metre setbacks where abutting a street. Brampton does not require additional parking for the garden suite itself, a significant advantage for constrained lots, though the main dwelling must maintain its required parking complement. Combined lot coverage for principal and accessory structures cannot exceed 40%.

The City requires garden suites to be connected to municipal services and prohibits individual well or septic systems. Brampton applies a sliding scale for maximum garden suite size: lots under 465 square metres are restricted to 70 square metres GFA, while lots over 650 square metres may achieve the full 90-square-metre maximum.

Vaughan implemented garden suite permissions through comprehensive Zoning By-law 1-88 amendments in By-law 004-2021, effective February 2021, with ongoing refinements through 2026. Garden suites are permitted in R1, R2, R3, and R4 residential zones subject to minimum lot requirements of 15 metres frontage and 450 square metres area. The maximum garden suite size is 80 square metres (861 sq ft), the smallest maximum in the GTA, with a 6-metre height restriction.

Minimum setbacks are 0.6 metres from rear and interior side lot lines. Vaughan uniquely requires one parking space specifically for the garden suite in addition to maintaining principal dwelling parking requirements, creating challenges on lots without rear lane access. The City mandates separate utility services including individual water and electrical metres for garden suites. Garden suites must be located entirely within the rear yard, defined as the area behind the rear wall of the principal dwelling.

Vaughan applies additional restrictions in areas subject to Region of York water capacity constraints, requiring Water and Wastewater Capacity Allocation approval before building permit issuance. The City prohibits garden suites on corner lots unless rear yard access is available from the flanking street. Maximum combined coverage is 40% of lot area, calculated including all buildings, structures, and paved areas.

Markham's garden suite regulations appear in Comprehensive Zoning By-law 2014-26, as amended by By-law 2020-87 adopted in June 2020, with streamlining updates implemented in 2024-2025. Garden suites are permitted as ancillary residential uses in detached dwelling zones where lots meet minimum dimensions of 15 metres frontage and 465 square metres area. Maximum gross floor area is 100 square metres (1,076 sq ft) with a 6.5-metre height limit accommodating two-storey construction.

Setback requirements are 0.6 metres from the rear lot line and 1.2 metres from interior side lot lines, with increased setbacks of 4.5 metres from street lines on corner lots. Markham does not require additional parking spaces for garden suites, though principal dwelling parking must be maintained. The City permits garden suite access from rear lanes, driveways, or designated pedestrian walkways meeting minimum 1.2-metre width.

Markham requires site plan control approval for garden suites exceeding 75 square metres, adding 6-8 weeks to approval timelines but ensuring comprehensive review of grading, drainage, and servicing. Combined lot coverage including all structures cannot exceed 40%, though the City offers minor variance opportunities where existing coverage approaches this limit. Garden suites must be designed with separate entrances from the principal dwelling and cannot share interior access.

Markham applies Urban Design Guidelines requiring garden suite design compatibility with principal dwelling architectural character, including complementary materials, roof forms, and window proportions.

Oakville governs garden suites through Zoning By-law 2014-014, amended by By-law 2020-057 effective July 2020, with design guideline updates implemented in 2025. Garden suites are permitted in R1, R2, and R3 zones subject to minimum lot standards of 15 metres frontage and 465 square metres area. Maximum building size is 100 square metres (1,076 sq ft) with a 6-metre height restriction limiting most construction to 1.5 storeys with loft configurations.

Required setbacks are 0.6 metres from the rear lot line and 0.9 metres from interior side lot lines, with increased 3-metre setbacks from flankage streets on corner lots. Oakville requires retention of one parking space for the principal dwelling but does not mandate additional parking for the garden suite, though vehicular access must be maintained.

The Town applies distinctive architectural controls requiring garden suite exteriors to complement the principal dwelling through matching or compatible materials, colour schemes, and roof pitches within 15 degrees. Garden suites must be located entirely in the rear yard, with rear yard depth calculated from the rearmost wall of the principal dwelling. Oakville prohibits garden suites in Lakeshore Character Areas and Old Oakville Heritage Conservation Districts without Committee of Adjustment variance.

Combined lot coverage cannot exceed 40% including all buildings and structures over 1 square metre. The Town requires Tier 2 water efficiency standards for garden suites, mandating low-flow fixtures achieving maximum 4.8 litres-per-minute flow rates.

As part of the City of Toronto, Scarborough follows the city-wide garden suite and laneway suite provisions in Zoning By-law 569-2013, with Chapter 200 amendments adopted in 2018, expanded in 2022, and streamlined through 2025. Toronto permits garden suites (termed 'laneway suites' in areas with lane access) as-of-right in detached and semi-detached residential zones. Maximum gross floor area is 100 square metres (1,076 sq ft) with a 6-metre height limit generally restricting construction to single storeys with loft spaces.

Minimum setbacks are 0.5 metres from the rear lot line and 0.9 metres from interior side lot lines, the most permissive setback standards in the GTA. Toronto requires no additional parking for garden suites, and existing parking requirements for the principal dwelling may be waived where lot constraints exist. Garden suites in Scarborough predominantly require laneway access, as the By-law restricts rear yard access through side yards in most established neighbourhoods to protect tree canopy and landscaped open space.

The City applies a 40% lot coverage maximum including all structures. Toronto's Municipal Code Chapter 441 requires Toronto Green Standard Tier 1 performance for garden suites, including enhanced insulation (R-24 walls minimum), Energy Star appliances, and LED lighting throughout. Heritage Permit approval is required for properties in Heritage Conservation Districts, adding 4-6 weeks to approval timelines.

Garden suites must connect to municipal water and sanitary services, with the City offering a Garden Suite Servicing Grant covering up to $32,000 of water and sewer lateral connection costs (increased from $25,000 in 2024).

North York, as part of amalgamated Toronto, follows City-wide garden suite and laneway suite regulations in Zoning By-law 569-2013 applicable to former North York properties within the new By-law's geographic scope, with Zoning By-law 7625 still applying to areas not yet transitioned. Garden suites are permitted in residential zones allowing detached and semi-detached dwellings where lot dimensions support rear yard construction.

Maximum building size is 100 square metres (1,076 sq ft) with 6-metre height restrictions favouring single-storey designs with loft bedrooms. Setbacks require 0.5 metres from rear lot lines and 0.9 metres from interior side lot lines, matching Toronto's city-wide standards. North York areas feature extensive rear lane networks in neighbourhoods developed 1950-1970, making laneway suite configurations particularly viable.

No additional parking is required for garden suites, and Toronto waives principal dwelling parking where the garden suite occupies former parking areas, subject to Committee of Adjustment minor variance. North York applies a 40% maximum lot coverage combining all structures. The City requires garden suites to meet Toronto Green Standard Tier 1, including enhanced envelope performance (effective R-32 ceiling insulation) and water efficiency measures (dual-flush toilets maximum 4.8/3.0 litres per flush).

Properties in Yonge Street Heritage Conservation District require Heritage Permit approval through Toronto Preservation Services. North York has higher-than-average basement water infiltration, and the City strongly recommends foundation drainage systems with sump pump connections for garden suites, particularly in areas with high water tables near the Don River valley system.

Etobicoke, as part of the City of Toronto, applies garden suite and laneway suite provisions from Zoning By-law 569-2013 with area-specific considerations for former Etobicoke planning districts. Garden suites are permitted as-of-right in residential zones permitting detached and semi-detached dwellings, with a unique minimum lot depth requirement of 30 metres to ensure adequate rear yard area remains after garden suite construction. Maximum building size is 100 square metres (1,076 sq ft) with 6-metre maximum height.

Required setbacks are 0.5 metres from rear lot lines and 0.9 metres from interior side lot lines. Etobicoke's deeper lot configurations, typical of post-war subdivision patterns, often provide superior garden suite development potential compared to narrower Toronto and East York lots. No additional parking is required for garden suites, and Toronto permits reduction or elimination of principal dwelling parking through Committee of Adjustment minor variance applications where lot constraints exist. Maximum lot coverage is 40% including all buildings and structures.

Etobicoke areas near Etobicoke Creek and Mimico Creek require garden suite foundation design addressing flood plain regulations in accordance with Toronto Municipal Code Chapter 754, potentially requiring elevated first floor construction. Garden suites must meet Toronto Green Standard Tier 1 including enhanced air tightness (maximum 2.5 air changes per hour at 50 Pascals). Properties in Etobicoke's four Heritage Conservation Districts (including Mimico-by-the-Lake) require Heritage Permit approval.

Toronto offers expedited Building Permit review for garden suites using pre-approved design templates through the Laneway Suite Design Catalogue program, reducing approval timelines from 12-16 weeks to 6-8 weeks for qualifying applications.

Richmond Hill permits garden suites through Comprehensive Zoning By-law 66-18, as amended by By-law 115-20 adopted in October 2020, with process improvements implemented through 2025. Garden suites are permitted in detached residential zones (Residential Detached One and Two) where lots meet minimum standards of 18 metres frontage and 550 square metres area, the highest lot area threshold in the GTA.

Maximum garden suite size is 90 square metres (969 sq ft) with a 6-metre height limit permitting two-storey construction with reduced ceiling heights. Required setbacks are 1.0 metre from rear lot lines and 1.2 metres from interior side lot lines, the most conservative setback requirements among surveyed municipalities. Richmond Hill requires one parking space specifically for the garden suite in addition to principal dwelling parking, creating significant access challenges on lots without rear lanes.

Garden suites must be entirely located in the rear yard and set back minimum 18 metres from the front lot line. Maximum combined lot coverage is 40% including all structures, with additional restrictions in Oak Ridges Moraine Conservation Plan areas reducing maximum coverage to 20%. Richmond Hill applies Site Plan Control approval requirements for all garden suites, mandating detailed grading plans, landscaping plans showing tree preservation, and servicing plans prepared by licensed engineers.

The approval process typically extends 10-14 weeks beyond standard building permit timelines. Garden suites must connect to municipal water and sanitary services, with the Town requiring separate utility metres and individual service laterals where lot dimensions permit. Richmond Hill prohibits garden suites on lots subject to Regional storm water management easements, affecting numerous properties in subdivisions developed after 2000.

The Town requires Sustainable Design and Construction requirements including enhanced insulation (R-28 walls, R-50 ceilings), Energy Star windows (maximum U-0.27), and third-party energy modelling for suites exceeding 75 square metres.

Garden suite enabling legislation stems from Ontario's More Homes, More Choice Act, 2019 (Bill 108), which amended the Planning Act to require municipalities to permit second residential units in ancillary structures. Section 16(3) of the Planning Act requires official plans to authorize second units in detached, semi-detached, and rowhouse dwellings, as well as ancillary structures.

The Planning Act amendments prevent municipalities from prohibiting second units outright, though municipalities retain authority to establish dimensional standards, location requirements, and design criteria through zoning by-laws. Ontario Building Code Section 9.34 governs construction standards for secondary suites, requiring compliance with Part 9 housing provisions for buildings under 600 square metres and three storeys.

The Building Code mandates one-hour fire separation between dwelling units in the same building, though garden suites as detached structures require only standard Part 9 construction without fire separation upgrades. Ontario Regulation 332/12 under the Building Code Act exempts garden suites from Development Charges where the suite is under 100 square metres, providing significant cost savings averaging $18,500-36,000 depending on municipality (adjusted for 2026 DC rates).

The Ontario Heritage Act Section 42 requires heritage permits for alterations to properties designated under Parts IV or V, including garden suite construction, with Toronto Heritage Preservation Services, Markham Heritage Section, and other municipal heritage committees reviewing applications for design compatibility. Provincial Policy Statement (2020) Section 1.4.3 directs municipalities to establish minimum standards for housing, including authorization of additional residential units, while maintaining municipal authority over built form and neighbourhood character.

Ontario's Environmental Protection Act requires garden suites to connect to municipal sewage systems where available, prohibiting septic systems in urban serviced areas, with Ministry of Environment approval required for any rural garden suites proposing septic service.

Despite variation in dimensional standards, GTA municipalities share core garden suite requirements establishing baseline expectations for contractors and homeowners. All surveyed municipalities require garden suites to be ancillary to detached or semi-detached principal dwellings, prohibiting garden suite construction on vacant lots or as primary dwellings. Garden suites cannot be severed into separate ownership, ensuring the property maintains single legal title with both dwelling units.

Minimum lot sizes range from 450-550 square metres, with all municipalities requiring sufficient lot area to accommodate both structures while maintaining required yards, setbacks, and landscaped open space. Municipal water and sanitary sewer connections are mandatory where services exist, with all municipalities prohibiting individual wells or septic systems in serviced urban areas.

Garden suites must comply with Ontario Building Code Part 9 construction standards including foundation design for frost protection (minimum 1.2-metre depth below grade), wall insulation (minimum R-20 effective), ceiling insulation (minimum R-40), and window performance (maximum U-0.28). All municipalities require separate entrances for garden suites without shared interior access to the principal dwelling, maintaining the units as legally separate dwellings.

Maximum lot coverage restrictions of 35-40% apply universally, calculated including all buildings, covered porches over 1 square metre, and in some municipalities, uncovered decks over 0.6 metres above grade. Heritage property restrictions appear in all municipalities, requiring additional approval processes for properties in Heritage Conservation Districts or individually designated under the Ontario Heritage Act.

Garden suites must maintain minimum 0.5-1.0 metre setbacks from rear and interior side lot lines, with increased setbacks of 3-4.5 metres from flanking streets on corner lots. All municipalities restrict garden suite height to 6.0-6.5 metres, effectively limiting construction to single storeys with loft spaces or modest two-storey designs with reduced ceiling heights. Fire safety requirements include smoke alarms on all levels, carbon monoxide detectors where fuel-burning appliances exist, and emergency egress windows in bedrooms meeting minimum 0.35-square-metre openable area.

Electrical service requires separate panels for garden suites with minimum 100-amp service capacity, installed by licensed electricians to Ontario Electrical Safety Code standards. Plumbing installations must include backwater valves where garden suite fixtures are below the main sewer lateral elevation, protecting against sewage backup during storm events. Municipalities universally prohibit short-term rentals in garden suites, requiring tenancies of minimum 28-30 consecutive days under municipal licensing and regulatory by-laws.

All municipalities require building permits for garden suite construction with standard fees ranging $9,800-18,500 plus development charges where applicable (2026 fee schedules), with permit timelines of 8-16 weeks for complete applications meeting all zoning requirements.