Secondary Suite
Bylaws in Chilliwack.

The reasons people build secondary suites in Chilliwack are rarely about code. They're about money, family, and practicality. Rental income to help carry the mortgage. A self-contained space for aging parents. A place for adult kids who haven't quite launched yet. Or a place they'll rent out after they launch, which helps fund retirement.

What stops most people isn't the desire. It's the paperwork and the code. What follows is the plain-English version of both, specific to Chilliwack and current as of 2026. By the end, you'll know whether a suite is realistic for your property, what the main requirements are, and what to ask a contractor about permits and execution.

Where secondary suites are allowed in Chilliwack

Zoning matters more than most homeowners realize. Most single-family lots in Chilliwack (R1, R2, and equivalents) allow a secondary suite, but “most” isn't “all.” Check before you commit.

Some areas have additional restrictions layered on top of zoning. Certain hillside neighborhoods, gated subdivisions, and newer developments may have restrictive covenants written into the subdivision agreement. These show up on title but aren't visible in zoning maps.

How to check: the City of Chilliwack's zoning lookup tool (chilliwack.com) lets you enter your address and see what your zoning allows. If you see anything that looks like a restriction, check your title documents next, or ask a contractor who's done suites in your area.

The six main requirements for a legal suite

1. Separate entrance

The suite needs its own exterior entrance. Not a door that requires walking through the main home's living space to reach. Most basement suites use an existing walkout door or cut a new one through an exterior wall. Side-door access is usually preferred over rear access if both are possible.

2. Egress window in each bedroom

Every bedroom in a legal suite needs an egress window, large enough for someone to climb out of in a fire. The BC Building Code specifies minimum width, height, and the smallest dimension of the opening. For most basement conversions, this means cutting or enlarging windows.

If the window is below grade, it also needs a properly sized window well with clear egress path. This is where a lot of DIY suite conversions fail inspection.

3. Fire-rated separation

A 45-minute fire-rated separation is required between the suite and the main home. This means specific drywall assemblies on the ceiling and any shared walls, usually two layers of 5/8” Type X drywall with proper joint sealing. Heating ducts crossing the separation need fire dampers. Smoke alarms in both units must be interconnected.

4. Independent heating

The suite needs its own controllable heating system. Options include: baseboard heaters, a mini-split heat pump, or a separable zone on the main home's furnace with its own thermostat. Just piping forced air from upstairs isn't enough.

5. Proper ventilation

Kitchen and bathroom exhaust fans must vent to the exterior, not into the attic or ceiling space. Suites also need a fresh air intake meeting code requirements for continuous airflow. Older homes often need new ductwork routed to meet these requirements.

6. Separate electrical sub-panel (usually)

Most legal suite conversions require a separate electrical sub-panel for the suite's circuits. This often triggers a service upgrade on older homes with 100A main service, because the main panel doesn't have capacity to add a sub-panel for a second dwelling unit.

Parking, occupancy, and other considerations

Beyond the building code, there are zoning requirements that catch people off-guard:

• Parking. Most Chilliwack zones require one parking stall per secondary suite. If your driveway only fits two cars and both are already in use, you need a plan.
• Occupancy limits. There are maximum number of unrelated persons limits in some zones. Not usually a practical issue, but worth knowing.
• Short-term rentals.If you're planning to use the suite as an Airbnb, check the City's short-term-rental rules first. They've changed in recent years and could continue to.
• Property tax and insurance. A legal suite can affect your property tax assessment and usually requires a home insurance update. Talk to your accountant and insurer before committing.

Realistic timeline and cost

A straightforward basement suite conversion takes 8–14 weeks from demo to occupancy permit, assuming permits are in hand. Garage suites and above-garage suites take longer, usually 4–8 months. Chilliwack permit timing as of 2026 is running 6–10 weeks for building permits.

Cost ranges widely based on scope. A simple basement conversion can be on the lower end, while a suite requiring significant service upgrades or egress window cuts can run higher. A site visit gets you a real number based on your specific property. For more on how a basement suite fits into the broader spectrum of basement work, see our basement renovations page. If your lot points toward a coach house or above-garage suite instead, our additions and legal suites page covers those paths.

The five most common mistakes

1. Assuming the basement can be a legal suite without checking zoning first. Flagged as #1 for a reason. Start here.
2. Underestimating the electrical service upgrade.Older Chilliwack homes with 100A service often can't handle a second unit without upgrading. This is easily $5k–$8k that surprises people.
3. Skipping egress window requirements.Bedrooms without proper egress aren't legal bedrooms. Affects occupancy permit and insurance.
4. DIY or unlicensed work on electrical or plumbing. Failed inspections, voided insurance, issues on home sale.
5. Not planning for drain routing. Below-grade bathrooms usually need a sewage ejector pump. Easy to miss until the plumber shows up.

What to ask a contractor

• “Have you built legal suites in Chilliwack specifically?”
• “Do you pull the electrical and plumbing permits directly?”
• “What happens if the permit inspector finds something during construction?”
• “Can you show me examples of completed legal suites with occupancy permits?”
• “How do you handle the service upgrade if my panel needs it?”

The bottom line

A legal secondary suite is a substantial project, but not as complicated as it first looks when you have a contractor who's done them before. The biggest unknowns (zoning, service capacity, drain routing) can all be resolved at a site visit before you commit. The execution risks (permits, inspections, code requirements) are known quantities for anyone who's done this work in Chilliwack.

If you're thinking about a suite, start with the zoning check. Then get a contractor out to walk the space and tell you honestly what's possible, what's required, and what it will actually take.