Why RTO4 could put a floor under Ottawa's office vacancy

For five years, the Government of Canada did everything short of a fire sale to get out of office space in Ottawa. It let leases lapse, handed back whole floors, and told anyone who asked that the portfolio was going to shrink by half. Then on July 6 it ordered public servants back to their desks four days a week, and quietly admitted it doesn't have enough desks. That is the whole Ottawa office story in one sentence, and it changes how you should read the vacancy number.

The 14.3% everyone quotes

Ottawa's office vacancy hit 14.3% in the first quarter of 2026, up a full point in three months, per CBRE. While the rest of the country is recovering, with national vacancy falling four quarters in a row to around 17.1%, Ottawa is the one major market still drifting the wrong way. The reason isn't mysterious. The federal government is the anchor tenant for this city, and it spent 2025 and early 2026 giving space back. Three suburban blocks tell the story: 114,000 square feet at 1550 Carling, 112,000 at 59 Camelot Drive, 73,000 at 700 Silver Seven Road. Across the whole portfolio, the feds have shed something like a million square feet of privately leased space over five years.

So the headline reads like a market in trouble. The headline is also about to get a new input.

Then RTO4 landed

The four-day return-to-office mandate, RTO4, took effect July 6. It moves public servants from three days in the office to four, and departments are phasing it in through September 15 because, in plain terms, they can't fit everyone at once. Global Affairs and Health Canada have already flagged that they're short on room. Public Services and Procurement Canada, the department that was supposed to be selling and subleasing its way to a portfolio half the size, has quietly walked that target down to roughly a third and now says it may have to acquire space to seat everyone.

Read that again. The single biggest reason Ottawa's vacancy climbed is now the reason it might stop. The same landlord that gave back a million square feet just bought a 14-storey building at 131 Queen Street for $148.2 million in March. When your largest office user flips from net seller to occasional buyer, the absorption math changes fast.

Why this won't rescue every empty building

Here's the part that separates a real read from a headline. RTO4 creates demand for functional, connected, downtown desks. It does nothing for a 1980s block off Silver Seven Road that nobody wants at any price. The vacancy figure is really two markets wearing one number. Good space near the LRT is about to tighten. Stranded suburban and Class B space stays stranded, which is exactly why office-to-residential conversion keeps coming up for the genuinely dead stock. Averaging those two together into "14.3%" hides more than it tells.

That split matters if you own or lease. A landlord holding renovated downtown space is walking into more leverage than they've had since 2019. A landlord holding a tired suburban tower is still competing on tenant inducements, the free rent and fit-up dollars, and will be for a while. Same city, same quarter, opposite trajectories.

What I'd actually do with this

If you have capital pointed at Ottawa office, stop underwriting off the citywide vacancy rate. Underwrite the specific building: its age, its distance to transit, and whether the federal footprint around it is growing or shrinking. A Class A tower inside the RTO4 demand zone is a different asset than a suburban block with a government lease rolling in 18 months, even if a spreadsheet files them under the same heading.

If you're a small business hunting for space, the calculus flipped. The best downtown deals were a function of federal weakness, and that weakness is fading in the good corridors. If you want distress pricing now, you'll find it further out, in the buildings the government is finished with.

And if you're comparing office to the rest of commercial, keep some perspective. Industrial vacancy in Ottawa is still around 2.5% by Colliers' count, with net rents easing slightly to the mid-$16s per square foot after years of climbing. That's a tight, stabilizing market, not a distressed one. Office is the segment with the story this year, and the story just got more interesting. I broke down all three segments in retail vs office vs industrial if you want the fuller comparison.

The caveat I won't skip

None of this is a done deal. CBRE frames the turn as something that could reverse negative absorption and deliver a vacancy decline over the back half of 2026, not something that already has. The public service unions are still grieving RTO4, and if the mandate gets watered down, the demand thesis softens with it. The phase-in runs to mid-September, so the real absorption won't show up cleanly until the Q3 and Q4 numbers land. What I'm confident about is narrower and more useful: the one-number version of Ottawa's office market is now actively misleading, and anyone making a decision off it is flying blind.

If you're weighing an office purchase, a lease renewal, or you just want to know which side of the vacancy split a particular building sits on, that's the exact read I do for commercial clients. Call me at 613-262-6545 or email fil@613realtor.ca, and we'll look at the building instead of the headline.