Milton zoning for small homes

Backyard suite

A separate home in the yard of a house: garden suite, laneway suite or coach house, including prefab, modular or container units used this way.

Allowed · Milton’s term: “additional dwelling unit in an accessory building (detached ARU / coach house)”

In the urban area one additional dwelling unit may be located in an accessory building on a lot with a detached, semi-detached, semi-link or townhouse dwelling, as part of up to three additional units per lot. Units must be on municipal water and wastewater (unserviced low density lots need 1.5 ha for a detached unit); rural zones under By-law 144-2003 have narrower permissions, including none in the Greenbelt Natural Heritage System or the Escarpment Natural and Protection Areas. [1][2][3]

Number allowed: Up to 3 additional dwelling units per lot; not more than 1 in an accessory building (By-law 016-2014, s.4.10 ii-iii) [4]
Maximum size: Accessory building: gross floor area not more than 10% of lot area or 110 m², whichever is less (s.4.2.5 vi); in a detached garage, unit floor area not more than the principal dwelling's floor area or 110 m², whichever is less (s.4.2.2) [4]
Maximum height: 3.5 m flat roof; 4.3 m gable, hip, gambrel or mansard roof (s.4.2.5 vii) [4]
Setbacks: Rear or interior side yard only; 1.2 m from interior side lot line; 1.5 m from rear lot line; no closer to exterior side lot line than the principal building (s.4.2.5) [4]
Separation from house: 3.5 m from the principal building (s.4.2.5 v) [4]
Servicing: Must be served by municipal water and wastewater; in an unserviced low density residential zone a lot with an ADU in an accessory building needs a minimum lot area of 1.5 ha (s.4.10 iv-v) [4]
Where allowed: Rural By-law 144-2003 (amended by 004-2026): detached units in RLD, RMD1, RMD2, RE, RV and A1 zones subject to s.4.25; not permitted in the Greenbelt Natural Heritage System or the Escarpment Natural/Protection Areas, and in the Greenbelt Protected Countryside only within an existing accessory building [1]

Ontario-wide rule

Ontario law stops municipalities from banning one residential unit in a building ancillary to a detached house, semi-detached house or rowhouse on a parcel of urban residential land, as long as the lot has no more than three units in total. Municipalities still set most other zoning rules, but provincial law limits parking requirements, minimum unit size, lot coverage and separation distances. These units are also exempt from development charges and parkland dedication. [5][6][7]

Tiny home on a foundation

A small house as the main home on its own lot. The key rule is any minimum dwelling size.

Allowed · Milton’s term: “detached dwelling”

Neither the urban By-law 016-2014 nor the rural By-law 144-2003 sets a minimum floor area for a detached dwelling in the residential or rural zones; lot area, frontage, setbacks and coverage still apply. [1]

Minimum dwelling size: No minimum dwelling floor area found in the residential or rural zone standards of By-laws 016-2014 or 144-2003 [4]

Ontario-wide rule

Ontario law sets no minimum total size for a house that is the main dwelling. The Building Code sets minimum room areas, so the smallest compliant dwelling is roughly 17.5 m² by the Province's own estimate. Municipalities may still set minimum floor areas for main dwellings in their zoning by-laws. The provincial ban on minimum sizes covers only additional residential units. [5][8][9][10][11][12][13]

Tiny home on wheels or park model

Living full-time in a tiny home on wheels or a park model home.

Needs approval · Milton’s term: “mobile home dwelling / garden suite”

Recreational trailers are defined as short-term travel vehicles that may only be parked or stored on residential lots, and a mobile home dwelling is not a listed permitted residential use; the rural by-law mentions mobile homes only as an accessory farm dwelling. The rural by-law states that a garden suite (a portable detached unit) is not permitted as of right in any zone and is permitted through a temporary use by-law. [4]

Temporary garden suite: Garden suite: detached portable residential structure accessory to an existing dwelling, permitted through a temporary use by-law; not permitted as of right within any zone (By-law 144-2003, definitions and s.4.1 iv) [1]
Where allowed: Mobile home dwelling appears only within the definition of accessory farm dwelling (necessary for an agricultural operation) (By-law 144-2003 and 016-2014 definitions) [1]
Parking: Urban area: not more than one trailer or recreational vehicle parked outdoors per lot, 3.0 m height or less (By-law 016-2014, s.5.17) [4]

Ontario-wide rule

Ontario has no single rule for living full-time in a tiny home on wheels. A unit on wheels can count as a 'building' that needs a permit and must meet the Building Code once it stays in one place, is hooked up to services or is anchored. Park model trailers are recognized only as seasonal recreational buildings. Municipalities may allow a portable garden suite under a temporary-use by-law for up to 20 years, with extensions of up to 3 years each. [13][8][5][10][9]

Bunkie or sleeping cabin

A small sleeping building with no kitchen, usually beside a cottage or house.

Not allowed · Milton’s term: “detached accessory building”

Both by-laws state that a detached accessory building or structure is not to be used for human habitation unless specifically permitted, and neither permits a sleeping cabin or bunkie. [4]

Approvals: Detached accessory buildings may not be used for human habitation unless specifically permitted (By-law 144-2003, s.4.1 ii; By-law 016-2014, s.4.1 ii) [1]

Ontario-wide rule

Ontario law has no rule written specifically for bunkies or sleeping cabins. Whether one needs a building permit depends on the Building Code Act's definition of 'building' and the Code's shed exemption. That exemption covers only storage-use sheds, so it does not cover a structure used for sleeping. Municipal zoning rules for accessory buildings still apply. [10][8][5][14]

Official links

Last confirmed October 2026.

Notes and caveats

Two parent by-laws: 016-2014 (HUSP urban area, March 2026 consolidation) and 144-2003 (rural, March 2026 consolidation), both read from links on https://www.milton.ca/business-development/building-and-renovating/zoning/zoning-by-laws-and-maps/. The inventory URLs (milton.ca/en/...pdf) and the old ARU page now return 404 after the site redesign; working PDF links are on the new zoning page. The inventory note that rural ARU permissions were still under review is out of date: By-law 004-2026 added rural ARU permissions (s.4.25, s.4.1.1.3, s.4.1.2.2.1), and the Town's ARU page says the Official Plan and Zoning By-law were updated in January 2026. Milton has no waterfront residential zone; the bunkie answer reflects the general accessory-building rule.

Sources

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Milton zoning for small homes

Backyard suite

Ontario-wide rule

Tiny home on a foundation

Ontario-wide rule

Tiny home on wheels or park model

Ontario-wide rule

Bunkie or sleeping cabin

Ontario-wide rule

Official links

Sources

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