Can I Build a Duplex or Fourplex on My Lot in British Columbia?

British Columbia's small-scale, multi-unit housing rules changed what many owners of single-family and duplex lots can build. If you own one of these lots, you may be wondering whether you can now add units, or sell to someone who will.

The answer depends on your lot size, your location, your transit access and your municipality's current bylaw. This article walks through the main thresholds and the limits that still apply.

This article covers the law of British Columbia.

What the rules require

Under the Local Government Act, a local government zoning bylaw must permit the housing uses and densities set out in s. 481.3(3) to (5) by June 30, 2026, unless an exemption in s. 481.4 or the regulations applies. That date has now passed, but some local governments had extensions or are still adopting bylaws, so your municipality's current zoning is what you should check.

Bill 25 (2025) changed the rules. A zone where any parcel is restricted to duplexes and/or a single detached home is a Restricted Zone that must meet the minimum unit densities on all lots, and the definition now includes lots where a single detached home with a secondary suite and detached accessory dwelling unit is allowed.

The required use and density apply only where residential use is permitted on the parcel.

How many units: lot size and transit

A frequent transit bus stop means a route with a bus at least every 15 minutes on average, from 7 a.m. to 7 p.m. Monday to Friday and from 10 a.m. to 6 p.m. on Saturday and Sunday. The Act sets a higher minimum for parcels near a qualifying bus stop that meet a prescribed minimum size.

These unit numbers come from the Province's summary of the rules, so confirm them against current regulations and your municipality's bylaw.

Exceptions that can take your lot outside the minimums

• The 3 to 4 unit rule does not apply where the zone already allows three or more dwelling units on the parcel.
• Land not connected to a water or sewer system provided as a service by a municipality or regional district is exempt from the minimum unit counts in s. 481.3(4) and (5).
• Parcels larger than 4,050 square metres, and land in a zone whose minimum subdivision lot size is 4,050 square metres, are exempt from those minimums.
• Land protected under the Heritage Conservation Act, or designated under a heritage bylaw when the section came into force, is exempt from those minimums.

A local government that relies on one of these exemptions must give the minister written notice identifying the land and the exemption used. Even where a lot is exempt from the larger minimums, a secondary suite or detached unit is still generally allowed in single-family zones.

What local governments can still control

Local governments must not exercise development permit area designations or land use powers in a way that unreasonably prohibits or restricts the use or density the Act requires. A zoning bylaw also cannot use conditional density rules, such as amenity-based density bonuses, to reach the minimum units. Limited conditions are allowed on only one of the s. 481.3(5) units, and on units above the minimum.

If provincial regulations set siting, size, form or density standards, the local government must follow them and consider provincial guidelines. Specific height, setback and parking limits vary, so ask your municipality.

If your lot is in a designated development permit area, you generally need a development permit before subdividing or starting construction, unless an exemption applies. A development permit generally cannot vary permitted use or density, except hazard-related conditions, which may do so only as they relate to health, safety or protection of property.

What to do next

• Get your lot's size, and confirm its zoning in your municipality's current bylaw.
• Check whether your community has at least 5,000 people and whether a frequent transit stop is nearby.
• Find out whether your lot is serviced by municipal water and sewer, is over 4,050 square metres, or has heritage protection.
• Ask whether a development permit area applies to your lot.
• Ask what building permits and development cost charges would apply to the number of units you plan.
• Confirm that you are not in the Agricultural Land Reserve, where separate housing rules apply.

Being allowed to build a number of units is not the same as being ready to build them. A lawyer can check your title, covenants and bylaw before you commit to a project.

Frequently asked questions