Permits & Compliance · September 17, 2026 · 11 min read

Garden Suites & Legal Secondary Suites in BC: Rules, Cost and Process

Zoning is no longer the hard part. Under British Columbia's small-scale multi-unit housing legislation, secondary suites and accessory dwelling units are now allowed province-wide in single-family residential zones, and municipalities have had to rewrite their bylaws to say so. What decides whether a suite actually gets built is a different list: whether services can reach the rear yard, whether the ceiling height in the basement is legal, whether the setbacks and site coverage leave room, and which of two entirely different construction projects you are actually proposing. This guide separates those two questions — permission and feasibility — because conflating them is the single most common reason a garden suite project stops after the drawings. We build ground-up and we renovate occupied houses, which is to say both routes: see custom home building for a detached suite and home renovation for a suite inside the house.

Key takeaway. Permission is provincial: Bill 44 (2023), compliance deadline 30 June 2024, clarified and expanded by Bill 25 (2025) with a new deadline of 30 June 2026. Feasibility is local and physical — servicing, setbacks, site coverage and ceiling height. A secondary suite is a renovation inside a fire separation. A garden suite is a small new house with its own foundation and its own services.

What the Province Now Requires Your City to Allow

The small-scale multi-unit housing framework is the reason this topic changed. Two pieces of legislation matter.

Bill 44 (2023) — the Housing Statutes (Residential Development) Amendment Act — received royal assent in November 2023 and required local governments to update their zoning bylaws by 30 June 2024, except where an extension was granted.

Bill 25 (2025) clarified and expanded the requirements and set a new compliance deadline of 30 June 2026. Among other things it widened the definition of a "restricted zone" to include properties where a single detached house with a secondary suite and a detached accessory dwelling unit are permitted — which pulls the minimum density requirements across all lots in such zones.

What the province requires, as published on its own small-scale multi-unit housing page:

"Frequent" has a definition, and it is worth knowing before anybody tells you your lot qualifies for six: service at least every 15 minutes on average, between 7am and 7pm on weekdays and 10am to 6pm on weekends.

One caution that this guide will repeat. The legislation sets what zoning must permit. It does not override setbacks, site coverage, height limits, tree protection bylaws, servicing capacity or the Building Code. Six permitted units and a lot that can physically take six units are different statements.

Garden Suite or Secondary Suite: Two Different Projects

These get discussed as one topic because they come from one piece of legislation. As construction they have almost nothing in common, and the budget difference is roughly a factor of four.

The BC Building Code defines a secondary suite as a self-contained dwelling unit within a building, separated from the other parts of the building by a vertical fire separation with a fire-resistance rating, containing only one other dwelling unit, and where both units form a single real estate entity. That last clause is the one people are surprised by: neither unit can be strata-titled or otherwise subdivided — both remain registered under the same title.

What the Rules Look Like City by City

This is the part of the subject where honesty costs something, so here it is plainly: the provincial framework is uniform and easy to cite, and the municipal detail is neither. Bylaws change, several municipal sites do not serve their bylaw documents to automated requests at all, and a figure quoted from a contractor's blog is not a figure.

So the table below gives what was read directly from a municipal source on 17 September 2026, and says "not verified here" for the rest rather than filling it in. Check your own address before you design anything.

The three things to look up for your own address, in this order: what the zone permits as a second or third dwelling unit; the maximum floor area and height for a detached unit in that zone; and the rear and side yard setbacks plus maximum site coverage. The third one is what usually kills a garden suite, because a 75 m² building needs about 75 m² of yard plus setbacks on every side plus an access path plus whatever the tree bylaw protects.

The Code Requirements That Decide Feasibility

For a secondary suite inside the house, three Code requirements do most of the deciding. All three are measured before you design anything, and all three are cheaper to check than to discover.

Ceiling height. This is the first measurement to take in a basement, and frequently the last. Take it from the finished floor you intend to have — not from the slab — to the underside of the lowest duct, beam or pipe, not to the joists. A basement that measures adequately between the joists and inadequately under the main trunk duct is a basement where the mechanical has to be re-routed before anything else can happen.

Egress. The Code requires, at Sentence 9.9.10.1.(1), that each bedroom in an unsprinklered suite have at least one outside window or exterior door openable from the inside without the use of keys, tools or special knowledge. In a basement that usually means cutting a new window and excavating a window well, which means the foundation wall and the drainage both get involved.

Fire separation. A vertical fire separation with a fire-resistance rating, running continuously to separate the suite from the rest of the house. In an existing basement this is a ceiling assembly, a stair enclosure and sometimes a door upgrade — and it is the item most often skipped in an unpermitted suite, which is why an unpermitted suite is expensive to legalise.

One point worth knowing, because it differs from the rest of the country: the national model code caps the floor area of a secondary suite built with its lighter smoke-tight barrier option, at 80 m² and at 80 percent of the other unit. British Columbia's own provisions have historically taken a different approach, and BC has had secondary suite provisions in its Code since 1995. The province circulated a proposed change on 18 December 2025 to adopt the national smoke-tight barrier solution as an additional option. It was a public review draft, not law — so if somebody tells you BC now caps your suite at 80 m², ask them which edition they are reading.

For a garden suite, the Code questions are simply those of a small house, and the deciding constraints are almost always the servicing and the site rather than the Code.

What a Garden Suite Costs to Build

Planning ranges observed across Lower Mainland builders and published guides in September 2026. Not quotes. Suite sizes are given in square metres because that is how the bylaws state them.

The line that ruins garden suite budgets is almost never the building. It is servicing. Water, sanitary and electrical have to reach a structure at the back of the lot. That can mean trenching the length of the yard, a connection at the lane, an upgraded electrical service at the main house, and a sanitary connection whose depth is set by the existing main rather than by your preference. None of it is visible on an elevation drawing, and all of it is site specific — which is why a garden suite quote given without a site visit and a servicing check is a number, not a price.

The Build Process, in Order

1. Confirm the zoning permission for your specific address. Not the province's minimum — your zone, your lot size, your transit proximity.
2. Measure the constraints. Rear and side setbacks, maximum site coverage, maximum height, protected trees. This is where you find out whether 75 m² fits.
3. Get a servicing opinion before design. Where the sanitary main is, how deep, whether the existing electrical service has capacity. On a garden suite this is the budget.
4. Design to the bylaw and the Code together. A design that satisfies the zoning and fails ceiling height, or satisfies the Code and exceeds site coverage, is two rounds of redrawing.
5. Submit for the approvals in the right order. Zoning or development review where required, then the building permit. Tree permits and servicing approvals run alongside and have their own clocks.
6. Build. Foundation, framing, envelope, rough-in inspections, insulation, finishes.
7. Inspections and occupancy. Then registration, where the municipality requires the unit to be registered — Surrey's page notes that a coach house or garden suite may be treated as a dwelling unit requiring registration.

Where These Projects Fall Over

Site coverage, not floor area. Owners check the maximum suite size and skip the maximum site coverage. The second number is usually the binding one on a standard lot with an existing house and a driveway.

The servicing surprise. Discovered after design, priced after the owner has emotionally committed. Always get it looked at before drawings.

Ceiling height measured optimistically. Measured to the joists rather than to the underside of the ducts, and measured before the new floor assembly is added.

Assuming provincial permission overrides everything. It overrides zoning that prohibited the unit. It does not override setbacks, coverage, trees, servicing capacity or the Building Code.

Legalising an existing unpermitted suite. Almost always more expensive than building a new one, because the fire separation, the egress and the electrical all have to be exposed and corrected rather than simply built.

Confusing the two projects. A basement conversion and a detached suite are a renovation and a small new build. Budget them as what they are.

Conclusion

The province has done the part that used to be impossible: your city now has to permit a second unit on a single-family lot, and Bill 25 pushed the compliance date to 30 June 2026 for the municipalities still catching up. What is left is physical. Take the ceiling height honestly if the suite is going inside the house, and get a servicing opinion before a drawing exists if it is going in the yard — those two measurements decide more than any bylaw. Then read your own municipality's numbers rather than a summary of them, because Surrey publishes 35 to 75 m² and a $2,500 deposit and its neighbours publish something else. If the basement is the likely route, our basement renovation cost guide covers the living-space-versus-legal-suite decision in detail, and our custom home builder checklist applies in full to a detached suite, because that is what a garden suite is.