Legal suite is one of the most valuable phrases in a Calgary listing, and one of the least verified. It is a claim made by a seller, repeated by a listing, and often believed by everyone in the transaction until a lender or an insurer asks for proof.

Checking takes about a minute. Here is how to do it, what the answer actually proves, and what it costs you to get this wrong.

Four things have to be true at once:

  • The suite has the permits it needed. That means a building permit, usually an electrical permit, and sometimes plumbing and mechanical permits.
  • It meets the secondary suite standards in the National Building Code, Alberta Edition.
  • The use is allowed in that land use district, either as a permitted use or through an approved development permit.
  • It appears on the City of Calgary's secondary suite registry.

A suite that is safe and well built but never permitted is not a legal suite. A suite that was permitted but sits in a district where the use was never approved is not a legal suite either. All four conditions matter.

How to verify one before you buy

Search the address on the City of Calgary's secondary suite registry at secondarysuites.calgary.ca. Registration has been mandatory since June 1, 2018 under Bylaw 11M2018, and the entry attaches to the address rather than to the owner, so it carries across a sale.

Do this before you write an offer, not during your condition period. It is public, free and immediate, and it changes what the property is worth to you.

What the registry proves, and what it does not

A registry entry proves the suite passed inspection and is on the City's list as at the date it was added. It does not prove that everything done since was permitted.

A suite legalised in 2019 whose owner rewired it or moved a wall in 2023 without a permit is a legal suite with unpermitted alterations. The registry entry stays; the new work is still a problem. If the suite looks materially different from what a permit history describes, that gap is worth asking about directly.

What an illegal suite actually costs you

The consequences are financial and they arrive at inconvenient moments.

  • Financing. Lenders generally only count suite income toward mortgage qualification when the suite is legal. A buyer relying on that rent to qualify can lose the approval outright when the suite turns out to be unregistered.
  • Insurance. Coverage on an unpermitted suite can be limited or declined. This surfaces at renewal, or worse, at claim time.
  • Resale. Every future buyer runs the same check you are running now. An unregistered suite either sells for less or holds up the deal while it gets sorted out.
  • Timing. Discovery almost always happens during financing or during a condition period, which is exactly when there is no time to fix it.

For sellers the same facts run in reverse. If you have an unregistered suite, the cost of legalising it before listing is lower than the discount a buyer will ask for once their lender raises it.

The code requirements a suite has to meet

These come from the National Building Code, Alberta Edition, which has applied to secondary suites since December 31, 2006. They are also a practical checklist when you are standing in a basement trying to judge whether a suite is plausibly legal.

  • Minimum ceiling height of 1.95 m, which is 78 inches.
  • A smoke-tight separation between dwellings, built with 12.7 mm drywall.
  • A direct exit to the outdoors.
  • An egress window in every bedroom, at least 0.35 square metres in area, with no dimension under 380 mm, and 760 mm of clearance in the window well.
  • Interconnected smoke and carbon monoxide alarms covering both dwellings.
  • The furnace and water heater enclosed.
  • Independent heating and ventilation, for new suites.
  • Solid core doors, 45 mm, self-closing, in smoke-tight barriers.

Low ceilings and undersized bedroom windows are the two that most often stop an older basement from qualifying, and neither is cheap to fix. Check those first.

If you own an unregistered suite

Right now is the least expensive moment to deal with it that there has been in years.

The building permit to legalise an existing secondary suite is $205.92, including the 4 per cent Safety Codes Council fee. Development permit fees are currently $0, waived under the Suite Amnesty Program until December 31, 2026. Registry listing is also free until December 31, 2026.

Both of those waivers have an end date, which is the point. After December 31, 2026 the same work costs more.

The Secondary Suite Incentive Program, which offered up to $10,000 toward creating a suite, moved to a waitlist for new applications as of June 24, 2026. If you are counting on that money, confirm its status before you budget around it.

One caution on geography

Everything above is Calgary. Airdrie, Chestermere, Okotoks and Cochrane each administer their own land use bylaws and their own permit processes. The building code requirements are provincial and apply across Alberta, but the registry, the fees and the approval process described here are Calgary's. Do not assume a suite in Airdrie is governed by the same rules.