Zoning · Ottawa
The whole developable city is 7.8% of Ottawa
Two hundred and eighteen square kilometres out of two thousand seven hundred and ninety-seven. Inside that, the zones that permit apartments and shops are forty-five. This is the base zoning, by area, not the exceptions.
Ottawa's zoning by-law covers 2,797 square kilometres. That figure is worth pausing on, because it is the first thing that makes the rest of it make sense: the City's own published area is 2,778 km², so the layer is measuring the whole municipality and measuring it correctly.
Sorted by what the zoning is for:
| Zone group | km² | Share of Ottawa |
|---|---|---|
| Rural | 1,896.8 | 67.8% |
| Greenbelt, reserve and protection | 505.1 | 18.1% |
| Neighbourhood | 172.8 | 6.2% |
| Institutional, recreation, green | 124.1 | 4.4% |
| Mixed-use | 45.5 | 1.6% |
| Industrial and transportation | 32.8 | 1.2% |
| Special districts | 20.2 | 0.7% |
Eighty-six per cent of Ottawa is rural or protected. That is not a complaint — a city with a greenbelt has one on purpose, and farmland is not a missed opportunity. But it means every argument about where housing goes is an argument about the remaining fraction.
Add the two rows that hold housing and high street together and you get the number in the headline: 218.3 km², 7.8% of the city. Everything anybody builds, argues about, applies for or appeals happens inside that.
Inside the neighbourhoods, the ladder is bottom-heavy
The new by-law replaced the old R1–R4 with a graded ladder, N1 through N6, where a higher number permits a more intense form. By area:
| Rung | Max height | Max units per building | km² | Share of neighbourhood land |
|---|---|---|---|---|
| N1 | 8.5 m (11 m in Area E) | 4 | 36.2 | 20.9% |
| N2 | 8.5 m (11 m in Area E) | 6 | 43.7 | 25.3% |
| N3 | 11 m | 10 | 65.2 | 37.7% |
| N4 | 14.5 m | no cap | 16.7 | 9.7% |
| N5 | 30 m | no cap | 4.3 | 2.5% |
| N6 | per suffix or schedule | no cap | 2.3 | 1.4% |
| unserviced and other | — | — | 4.4 | 2.5% |
Heights and unit caps are Table 801A of the by-law. Put beside the areas, they say something the areas alone do not.
N1, N2 and N3 all cap out at 11 metres or less — and together they are 83.9% of Ottawa's neighbourhood land. Five sixths of the residential city is held at three storeys.
Then it steps. N4 is 14.5 m. N5 is 30 m — more than double N4, and the first rung where a building of any real size is permitted as of right. And N5 is 2.5% of neighbourhood land: 4.3 km² in a city of 2,797.
That is the cliff, and it is not in the height numbers alone. It is the unit caps beside them. N1 permits four dwellings per building, N2 six, N3 ten — whatever the lot. A 2,000 m² site zoned N3 permits the same ten homes as a 500 m² one. Above N3 the cap disappears entirely. So the ladder is not a gradient of size; it is a wall with a door in it at N4, and 83.9% of the land is on the near side.
The mixed-use city is 45 square kilometres
The zones that carry apartments over shops — the mainstreets, the hubs, the corridors — are the 1.6% row. Within them:
| Family | km² | Share of mixed-use land |
|---|---|---|
| Hub (H1–H3) | 15.5 | 34.0% |
| Mainstreet (MS1–MS2) | 14.5 | 31.9% |
| Neighbourhood mixed-use (NMU) | 9.3 | 20.4% |
| Minor corridor (CM1–CM2) | 5.6 | 12.3% |
| other codes | 0.7 | 1.4% |
The last row is small and is left in rather than rounded away: 0.66 km² sits in codes the layer writes with a subzone prefix — *_CM1B, *_NMU4 — which the four families above do not catch. A table that sums to 98.6% and says 100 is the kind of thing that costs an argument later.
Mainstreet is the one everybody pictures — Wellington, Bank, Preston — and it is 14.5 km² of a 2,797 km² city. Half of one per cent.
That is the context for something we measured separately. Ottawa's own Vacant Urban Residential Land Survey returns zero vacant parcels within six kilometres of Wellington and Holland. There is no empty land in the part of the city zoned for the buildings people are arguing about, so every home added there replaces something standing — inside 7.8% of the municipality, and for apartments over shops, inside 1.6%.
What this does not tell you
The mixed-use heights. The N-zone figures above are Table 801A. The equivalent for Mainstreet, Hub and Corridor is Part 9, and it is not summarised here — those zones carry their heights per subzone and per schedule, and reading them off correctly is a piece of work rather than a lookup. Until it is done, no metre figure is quoted for the 1.6%.
Area E of Schedule A1. N1 and N2 permit 11 m inside it and 8.5 m everywhere else, and this article does not say how much land is inside Area E. The 83.9% figure holds either way, because every rung in it caps at 11 m or below, but the split between 8.5 and 11 is unmeasured.
And the exceptions still matter. What the layer carries beyond the base rule is 1,898 polygons with an explicit H(n) height written into the zone code — MS1[1815] H(20), H2[3140] H(40). Those are 1.5% of the city's zoned area, and the bracketed numbers are site-specific exception references: H2[3140] points at By-law 2026-315. They are a register of permissions already granted on particular sites, not the standing rule — so reading them as "Ottawa's height limits" describes the exceptions and calls them the law. We published a piece that did exactly that this morning and pulled it; the retraction is on the file.
The base rule is the ladder. Five sixths of the residential city sits on rungs that permit three storeys and at most ten homes a building. And all of it happens on less than a twelfth of Ottawa.