Secondary suites, garden suites and laneway homes: how they count in a multiplex

What the law counts as a home

British Columbia's small-scale housing rules count housing units. Section 455 of the Local Government Act defines a housing unit as a self-contained dwelling unit. Each self-contained home counts as one: a basement suite, a laneway home and a unit in a fourplex alike.

Two parts of section 481.3 use that count. Subsection (3) covers a zone where only detached single-family houses are allowed. There, a city must allow at least one more housing unit, inside the house, in another building on the same lot, or both. Subsections (4) and (5) cover a wider set of zones, called restricted zones, and require a set number of units. B.C. Reg. 262/2023 sets that number at 3 for a lot of 280 square metres or less, 4 for a larger lot, and 6 for a lot of 281 square metres or more within 400 metres of a bus stop with a bus at least every 15 minutes on average.

The restricted zone definition in subsection (5.1) is useful here, because it lists the housing forms the law treats as the old single-family and duplex pattern: a detached house; a house with one extra unit inside it or on the lot; a house with one extra unit inside and one more on the lot; a duplex; and a duplex with one extra unit in each half, or one or two on the lot. A zone that allowed only those forms must now allow 3, 4 or 6 homes on the lots the law reaches. The provincial-rules chapter of the zoning guide covers which lots this reaches.

Secondary suites

The province's policy manual says the terms accessory dwelling unit and secondary suite carry their ordinary meaning. It describes an accessory dwelling unit as a building, or part of a building, that is a self-contained place to live, has cooking, sleeping and bathroom facilities, and is secondary to a main home on the same property. A secondary suite is an accessory dwelling unit located in, and forming part of, the main home.

The BC Building Code is narrower. It defines a secondary suite as a self-contained dwelling unit in a building, or in a portion of a building cut off by a vertical fire separation rated at least 1 hour, that contains only one other dwelling unit plus common spaces, where both homes form a single real estate entity. In plain words, a suite and its main home are one property with two homes. The manual adds that the code now allows secondary suites in more building types, including side-by-side units in duplexes and row housing, and that size limits on suites were removed from the code.

Being one property has a direct result. The manual states that the BC Building Code does not allow a secondary suite to be strata subdivided from its main home, and Burnaby's R1 summary says suites must stay on the same title as the main home for that reason. A buyer of a strata home that contains a suite buys the suite with it, on one title.

Cities add their own limits. Surrey defines a secondary suite as an accessory home whose habitable floor area is no more than 40 percent of the main home it sits in. Surrey allows suites in a single family dwelling, a duplex or a semi-detached building, and never in a houseplex. Burnaby allows one suite per principal home and, in its July 2026 summary, sets a minimum suite size of 32.5 square metres. Vancouver's suite rules sit in its own zoning bylaw, which could not be opened for this guide, so check them with the City.

The manual also asks cities to remove owner-occupation requirements for secondary suites, meaning rules that the owner must live on the property. It says such rules limit the supply of rental homes, notes that they are regarded as questionable in law, and suggests handling noise or upkeep through other bylaws.

Garden suites, coach houses and laneway homes

These three names describe a small separate home on the same lot as a main building. Surrey defines a garden suite as a ground-oriented home that is separate from, and accessory to, a single family dwelling, duplex, semi-detached building or houseplex on the lot. A coach house in Surrey is also an accessory home, placed above or attached to a detached garage.

Laneway home is the common name where the small home sits at the back of the lot by the lane. Burnaby's R1 summary says buildings commonly called laneway homes are still permitted, including on lots without lanes, and are regulated the same as other single-family dwellings, which Burnaby calls principal buildings. So in Burnaby a laneway home is a main building in law, even though people name it by where it sits.

Size limits come from the zone. In Surrey's R3 zone a coach house must be at least 35 square metres and no more than 75 square metres, not counting the garage or carport, and a garden suite has the same 35 to 75 square metre range. Where the main building has not used the zone's full floor area, the rest can go to the coach house or garden suite, up to 120 square metres. These figures are from the Surrey consolidation that includes amendments adopted up to 21 September 2026.

A home at the back of the lot also sits near the lane, and lanes can carry overhead power lines. The province's policy manual points to BC Hydro's guidelines on vertical and horizontal clearance from overhead lines. It says horizontal separation can range from 3 to 6 metres, with more space needed for safe work, and that older garages may sit closer than the rules for new buildings allow. An existing garage position does not show where a new laneway home may go. Where BC Hydro is not the local electric utility, the manual says to ask that utility.

How suites and laneway homes add up to 3, 4 or 6

The policy manual asks cities to allow any combination of homes up to the unit limit. Its own list for a four-home lot is in the table below. Each line counts as four housing units for the province's purposes.

Cities have taken different paths. Burnaby counts secondary suites toward the total number of homes allowed on a lot. Surrey's R3 zone allows up to 4 homes on lots from 280 square metres to just under 4,050 square metres outside transit-oriented areas, and up to 6 on eligible lots in a Frequent Bus Stop Area, using a single family dwelling, a duplex or a houseplex as the principal building, with secondary suites, garden suites and coach houses as accessory homes. Vancouver's definition spreads 3 to 8 homes across one or more buildings on a site.

Parking rules count each home as well. Surrey's Part 5 requires 1 parking space per home for a secondary suite, coach house or garden suite, with no minimum on eligible lots in a Frequent Bus Stop Area. Section 525.2 of the Local Government Act bars a city from requiring off-street parking for the homes it must allow on a six-unit lot near frequent buses.

Limits to check before planning a suite or laneway home

Sewer service comes first. The policy manual advises that on properties under one hectare without a local government sewer, cities should allow only secondary suites and no detached accessory homes, to reduce the risk of groundwater pollution. Section 481.4 of the Local Government Act also removes the 3 to 6 unit minimums from land not connected to a water or sewer system run by a municipality or regional district.

Water from a well brings another rule. The manual notes that a duplex, or a lot with a detached accessory home, served by a well or other private water meets the definition of a water system under the Drinking Water Protection Act, which has its own design and permit rules. A house with only a secondary suite may be considered exempt.

Farmland has its own law. Inside the Agricultural Land Reserve, the manual says a zoning bylaw has no effect where it would allow more homes than the Agricultural Land Commission Act and its regulation allow. On those lots, cities update their bylaws to allow a secondary suite or an accessory home only as the farm regulation permits.

Ownership is the last check. A suite stays with its main home. If the plan is to sell homes one by one, each home needs to be a principal home, and the strata-ownership chapter of the ownership guide explains how that works.