Ottawa R3 Zoning Explained

If you're researching Ottawa R3 zoning, you should know upfront: R3 no longer exists as an active zoning designation in Ottawa. When the City of Ottawa adopted its new Zoning By-law in 2025, the old R3 designation, along with R1, R2, R4, and R5, which was retired and replaced by the new Neighbourhood (N) zone system.

This article covers what R3 meant under Ottawa's old by-law, what types of housing it permitted, and what zone has taken its place.

What Was Ottawa R3 Zoning?

Under Ottawa's former Zoning By-law 2008-250, R3 stood for Residential Third Density. It was a medium-density residential zone, permitting a broader range of housing types than R1 or R2, most notably row houses, townhouses, and triplexes.

R3 had the most subtypes of any residential zone in the old by-law, with designations running from R3A through R3Z and beyond. Some of the most common subtypes included:

• R3A – Allowed row houses and triplexes on standard lots
• R3B – Permitted low-rise residential buildings up to 3 storeys
• R3C / R3D – Progressively more density, sometimes allowing small apartment buildings
• R3E through R3Z – More specialized subtypes, often tied to specific neighbourhoods or planning contexts

What Was Permitted in Ottawa R3 Zones?

R3 zones generally permitted a mix of housing types, including:

• Single-detached and semi-detached dwellings
• Duplex dwellings
• Triplex dwellings
• Row houses and townhouses
• Low-rise apartment buildings (in higher R3 subtypes)
• Stacked townhouses
• Home-based businesses

R3 zoning was common in Ottawa's older inner-city neighbourhoods, areas with a mix of townhouses, triplexes, and low-rise apartments built from the 1960s through the 1990s.

Ottawa R3 Zoning Is No Longer in Effect

Ottawa's new Zoning By-law replaced all residential R-zones with a streamlined set of Neighbourhood (N) zones: N1, N2, N3, and N4. The intent was to simplify Ottawa's notoriously complex zoning system, the old by-law had dozens of R3 subtypes alone, and to allow more housing density across the city. Depending on the specific R3 subtype and its location, your property may now be classified as N2, N3, or N4.

What Replaced R3? The N3 and N4 Zones

Former R3 properties have generally been transitioned to either N3 or N4, depending on the density and context of the old subtype.

• N3 (Neighbourhood Third Density) – The primary replacement for lower-density R3 subtypes. N3 permits townhouses, row houses, and triplexes. See our full guide to N3 zoning.
• N4 (Neighbourhood Fourth Density) – Replaced higher-density R3 subtypes. N4 allows low-rise apartment buildings and higher unit counts. See our full guide to N4 zoning.

How to Confirm Your Property's New Zone

If your property was formerly R3, check GeoOttawa, the City of Ottawa's free online zoning map, to find your current N-zone designation. Search your address and enable the Zoning layer. Our guide also walks you through the process: How to Check Your New Zoning Classification in Ottawa.

What This Means for Builders and Investors

The transition from R3 to N3/N4 has significant implications for anyone looking to develop or redevelop in Ottawa's established neighbourhoods. Properties that previously had complex, subtype-specific restrictions may now benefit from clearer, more permissive rules under the N system. If you're considering a triplex build, townhouse development, or low-rise apartment project on a former R3 lot, the new by-law may have expanded what's possible.

Frequently Asked Questions About Ottawa R3 Zoning

Is Ottawa R3 zoning still active?

No. Ottawa's R3 zoning was replaced in 2025 when the new Zoning By-law came into effect. Former R3 properties are now classified under the Neighbourhood (N) zone system, typically N3 or N4.

What replaced R3 in Ottawa's zoning?

Most former R3 properties are now designated N3 or N4. N3 covers townhouses and triplexes; N4 covers low-rise apartment buildings and higher-density configurations.

Could you build a triplex in R3 in Ottawa?

Yes, most R3 subtypes permitted triplex dwellings. Under the new N3 zone that replaced lower-density R3, triplexes are still permitted and may be allowed in more configurations than before.

What was the difference between R2 and R3 in Ottawa?

R2 was primarily for single-detached, semi-detached, and duplex housing. R3 extended to triplexes, row houses, and low-rise apartments. Both have been replaced by the Neighbourhood zone system.

Why did Ottawa change its zoning system?

The new Zoning By-law was introduced to implement Ottawa's 2020 Official Plan, simplify a complex system with dozens of subzone designations, and allow more housing density in established neighbourhoods to address the housing shortage.

Did all R3 properties become N3 or N4?

Most did, but not all. Some former R3 properties may have been assigned N2 depending on local context. Check GeoOttawa to confirm your property's current designation.