Accessory Dwellings
As of July 2024, most residential properties in Castlegar can have up to four dwellings, including Accessory Dwellings (ADUs).
Development Services
What Are Accessory Dwellings?
An accessory dwelling is a smaller, secondary home located on the same lot as the main dwelling, such as a secondary suite, basement suite, carriage house, and garden suite.
Which Accessory Dwelling is Best for You?
Deciding which accessory dwelling is best for you depends on factors like available space, the number of existing dwellings, lot size, and your personal preferences.
Adding an accessory dwelling to your property through the building permit process offers several advantages:
- Generate additional income as a mortgage helper.
- Meet safety standards by complying with current building codes.
- May be easier to obtain insurance.
- Maintain and potentially increase the value of your home.
- Avoid potential resale complications by having an inspected and approved unit.
When deciding to add an accessory dwelling to your property, consider factors such as becoming a landlord, changes to property assessments, potential impacts on property taxes, and increased utility costs.
Learn more: gov.bc.ca/homesuitehome
The Province has commissioned digital designs free to the public that can be used by builders, designers and homeowners to build accessory dwellings.
Learn more: Standardized Housing Designs
A good resource to understand the pros and cons of each ADU type is ReHousing’s “Pick Your Project”.
Learn more: rehousing.ca/Pick-Your-Project
What are the Zoning Regulations?
- Use – Accessory dwellings are allowed in most zones.
- Floor area – A rule of thumb is less than half of the main house.
- Lot size – Lots over 280 square metres can have up to four dwellings, smaller lots can have up to three.
- Setbacks – Attached accessory dwellings have the same setbacks as the main house – in most zones, this is 4.5m from the front, 1.5m from the interior sides, 3m from exterior sides, and 6m from the rear. Detached accessory dwellings have the same setbacks as other accessory buildings – in most zones, this is 6m from the front, 3m from exterior side, and 1.5m from interior sides and rear lot line.
- Parcel coverage – Varies by zone but is generally 50% – this means half your lot can be covered in roof area.
- Parking – The lot must be able to accommodate one space per main house and 0.5 space per accessory dwelling.
Read the bylaw:
How Do I Start?
A good way to start your accessory dwelling project is by collecting some basic information about your home and property.
- Determine what your interior walls are made of: Check this by removing the faceplate of a light switch. Note how thick the material is.
- Measure your yard: Take rough measurements from your lot line to your house or locate the survey pins at the corners of your lot.
- Know where your servicing is: Find where your servicing comes into your house and lot. Locate your electrical panel and note how many amps it is.
To learn more about your property, visit the Request Property Information page.
Design Options
There are two different accessory dwelling guides, one for converting existing buildings (such as a garage) and another for new construction (such as an addition). Each contain a design guide with BC Building Code (BCBC) requirements. The BCBC requirements listed are a summary provided as a guide. Every project is unique and there may be further BCBC requirements. Please check the BCBC, your designer, or reach out to the City’s building staff. Visit City Hall during business hours to pick up an accessory dwelling guide.
Learn more about building at: castlegar.ca/buildingpermits
The BC Building Code (BCBC) options listed here are for the conversion of existing buildings. They are a summary intended as a guide. Every project is unique and there may be further requirements. Please check with the BCBC, your designer, or reach out to the City’s buildings staff.
What is required?
- Safe exiting and alarms – an exit door directly to the exterior and smoke/CO alarms.
- Bedroom windows – minimum clear opening area of 0.35m2 with no dimension less than 38cm.
- Electrical and gas – permits are from Technical Safety BC, typically taken out by your electrician or plumber.
- Ventilation – is required to provide fresh air to the dwelling.
- Homes older than 1990 – require a hazardous materials assessment.
- Heating systems – could be independent of the main dwelling or could be interconnected with the protection of fire dampers and a duct smoke detector to shut down the system.
- Ceiling height – is slightly relaxed for existing buildings.
- Plumbing – supply lines may need to be upgraded to meet the minimum BCBC requirements.
- Fire resistance – see construction options in the Design Guide.
- Sound transmission – see construction options in the Design Guide.
View construction options: Design Guide for Existing Buildings
Review the checklist: Accessory Dwelling Checklist
BC Building Code (BCBC) options for new construction, such as within a new house or as an addition to an existing building, are summarized here. Every project is unique and there may be further requirements that are not listed. Please check with the BCBC, your designer, or reach out to the City’s buildings staff.
View code requirements: Design Guide for New Buildings
Frequently Asked Questions
Parking must be accommodated on your property and is regulated by the Zoning Bylaw. Refer to Part 8: Parking in the interactive contents. Questions? Contact Development Services
| Type | Requirement | Total |
|---|---|---|
| Single Family Dwelling | 1 space | 1 space |
| Single Family Dwelling with Accessory Dwelling | 1 plus 0.5 spaces | 2 spaces* |
| Single Family Dwelling with 2 Accessory Dwellings | 1 plus 2 @ 0.5 spaces | 2 spaces |
| Single Family Dwelling with 3 Accessory Dwellings | 1 plus 3 @ 0.5 spaces* | 3 spaces |
*Note that parking is rounded up to a whole number
Utilities are billed per lot based on remote meter readings. Accessory dwellings are billed at 25% of the main dwelling base rate up to 7.5 cubic meters per month and at a consumption rate over and above (2025 rates). Curbside collection is the same rate per dwelling. Each dwelling can put out 2 recycle bins, 1 garbage cart, and 1 organics cart. See the Utility Rates page for more information. See also, How to Read Your Bill. Questions? Contact Financial Services
| Type | Water Base Rate | Sewer Base Rate | Curbside Pickup | Total per month* |
|---|---|---|---|---|
| Main Dwelling** | $36.95 per month | $32 per month | $24.08 per month | $93.03 |
| Accessory Dwelling*** | $9.24 per month | $8 per month | $24.08 per month | $41.32 |
*Plus any flows over 30m³ per month at the consumption rate
**Water consumption rate is $0.84 per cubic metre over 30m³ per month and sewer is $0.51 on all flows (2025 rates). From May to September, billing is capped at 30m³
***Water consumption rate is $0.84 per cubic metre over 7.5m³ per month and sewer is $0.51 on all flows (2025 rates). From May to September, billing is capped at 7.5m³
Have Questions?
Contact Development Services to learn more about adding an accessory dwelling to your property.