Ontario Zoning & Building Glossary

A building or structure that is subordinate to and located on the same lot as the main building. Examples include detached garages, sheds, and garden suites. Accessory buildings must comply with setback and lot coverage requirements.

A self-contained residential unit within or on the same property as an existing residential building. Ontario's Planning Act requires municipalities to permit at least two ARUs per lot (one within the main dwelling, one in an accessory structure).

The three-dimensional space within which a building may be constructed on a lot, as defined by setbacks, height limits, and lot coverage restrictions.

A municipal body that hears applications for minor variances and consents (severances). If your project does not comply with the zoning by-law, you may need to apply for a minor variance through this committee.

Permission granted by a municipality (through the Committee of Adjustment or Land Division Committee) to divide a parcel of land into two or more lots. Severance applications must demonstrate that the new lots meet all zoning requirements.

A public body established under the Conservation Authorities Act to manage natural resources within a watershed. CAs regulate development near wetlands, floodplains, shorelines, and other natural hazards. A CA permit may be required in addition to a building permit.

One-time fees levied by municipalities on new development to fund growth-related infrastructure (roads, water, sewer, parks). Charges vary significantly between municipalities and are typically calculated per unit or per square metre.

A room or suite of rooms used or intended to be used as a domicile by one or more persons, containing cooking, eating, living, sleeping, and sanitary facilities.

The ratio of a building's total floor area to the area of the lot on which it is built. For example, a FAR of 0.5 on a 1,000 sq ft lot means the maximum total floor area is 500 sq ft. Some municipalities use GFA/lot area instead.

The area of land adjacent to a watercourse that is susceptible to flooding during a regional storm event (typically the 100-year flood or the regulatory flood). Development is generally prohibited or heavily restricted in floodplains.

A detached, self-contained residential unit located in the rear yard of a property with an existing dwelling. Ontario's Planning Act now requires municipalities to permit garden suites (also called backyard homes or laneway suites in some areas).

The total floor area of a building measured from the outside of exterior walls, including all storeys. Typically excludes unfinished basements, garages, and open porches, though definitions vary by municipality.

The maximum permitted height of a building as defined in the zoning by-law. Height may be measured from average grade to the highest point of the roof, or to the midpoint of the roof, depending on the municipality.

The percentage of a lot that is covered by buildings and structures. For example, if the maximum lot coverage is 35% and your lot is 1,000 sq m, the maximum building footprint is 350 sq m. Lot coverage typically includes all buildings, decks, and covered structures.

The horizontal distance between the side lot lines measured along the front lot line (typically the street line). Minimum lot frontage requirements vary by zone and are critical for severance applications.

A small, site-specific exemption from a zoning by-law requirement. Applications are heard by the Committee of Adjustment and must meet four tests: (1) minor in nature, (2) desirable for appropriate development, (3) maintains the general intent of the by-law, (4) maintains the general intent of the Official Plan.

The provincial regulation that sets minimum standards for the design, construction, and occupancy of buildings in Ontario. Administered by local building departments through the building permit process.

A municipal policy document that sets out the long-term vision for land use and development. The Official Plan guides zoning by-laws and development decisions. It is approved by the province and must conform to provincial policy.

The section of the Ontario Building Code that governs on-site sewage systems (septic systems). Applies to properties not connected to municipal sewer. Covers system design, installation, and maintenance requirements.

The section of the Ontario Building Code that governs small buildings (residential buildings up to 3 storeys and 600 sq m). Most residential construction in Ontario falls under Part 9.

Fees charged by the municipality for processing building permit applications. Typically calculated based on the value of construction or the area of the proposed work. Separate from development charges.

Land regulated by a conservation authority under Ontario Regulation 41/24. Includes areas within and adjacent to wetlands, floodplains, shorelines, steep slopes, and other natural hazards. Development in regulated areas requires a CA permit.

A private on-site sewage treatment and disposal system, typically consisting of a septic tank and a leaching bed. Required for properties not connected to municipal sewer. Governed by OBC Part 8.

The minimum required distance between a building and a lot line (front, rear, side, or flankage). Setbacks are defined in the zoning by-law and vary by zone, building type, and lot configuration.

A municipal approval process that reviews the design and layout of a development, including building placement, parking, landscaping, grading, and stormwater management. Typically required for multi-unit, commercial, or industrial developments.

Land that is seasonally or permanently covered by shallow water, or where the water table is close to the surface. Provincially Significant Wetlands (PSWs) have the highest level of protection, and development is generally prohibited within and adjacent to them.

A municipal regulation that divides the municipality into zones and specifies what uses are permitted in each zone, along with development standards (setbacks, height, lot coverage, parking, etc.). The zoning by-law implements the Official Plan.

A document issued by the municipality confirming the zoning designation and permitted uses for a specific property. Often required for real estate transactions and building permit applications.