Kitchener's rules at a glance
These are the rules in section 4.12.3 of Kitchener's Zoning By-law 2019-051, which covers most of the city. Lots still under the older By-law 85-1 follow the same rules in its section 5.22.1.
| Rule | Kitchener, detached ADU |
|---|---|
| Units in the building | 1 or 2, with a maximum of 4 units on the lot in total |
| Footprint | 80 m² maximum (about 860 sq ft) |
| Lot coverage | All accessory buildings, including the backyard home, 15% maximum, within the 55% limit for all buildings |
| Height, house under 9.1 m tall | 4.5 m for a pitched or mansard roof, 3.0 m for a flat roof |
| Height, house 9.1 m or taller | 6.0 m for a pitched or mansard roof, 4.5 m for a flat roof |
| Rear and side setbacks | 0.6 m if the building is up to 4.5 m tall; 0.9 m if taller (0.6 m beside a lane) |
| Location | Not in the front yard, and not within 4 m of the back wall of the house |
| Minimum lot width | 10.5 m (or the zone's minimum, if higher) when the lot is more than 800 m from an LRT station and outside the Central Neighbourhood Area |
| Walkway | A clear path at least 1.1 m wide to the unit's entrance |
| Parking | None within 800 m of an LRT station or in strategic growth areas; 0.3 spaces per additional unit in the Central Neighbourhood Area; 0.6 elsewhere |
| Servicing | Full municipal services, through the lot's one set of service connections (separate meters are allowed) |
| Severance | Not allowed: the backyard home stays on the same lot as the house |
Height decides the living space
Kitchener caps the footprint at 80 m² but sets no separate limit on floor area, so the height limit is what decides whether you get a single storey or something more. The limit depends on the house in front of it:
- Behind a house under 9.1 m tall, which covers most bungalows and many two-storeys, a pitched roof can reach 4.5 m and a flat roof 3.0 m. For a pitched roof, height is measured to the midpoint between the eaves and the ridge.
- Behind a house 9.1 m or taller, the limits rise to 6.0 m for a pitched or mansard roof and 4.5 m for a flat roof. A building over 4.5 m tall also needs the larger 0.9 m setback from the rear and side lot lines.
A designer can tell you quickly what each limit means on your lot, and whether a loft or second level is realistic.
Will it fit on your lot?
- Lot width: away from the LRT and outside the Central Neighbourhood Area, the lot must be at least 10.5 m wide, or wider if the zone requires it.
- Distance from the house: the backyard home cannot sit in the front yard or within the 4 m strip behind the rear wall of the house.
- The walkway: at least 1.1 m wide with 2.1 m of clear headroom, no steeper than 8% (4% across), and no more than 30 m to the unit's entrance (or 60 m to its most remote room). Meters and downspouts may project 0.2 m into it, and it cannot start from the rear lot line.
- Coverage: the backyard home shares the 15% accessory building allowance with any garage or shed. On a lot with three or four units, at least 20% of the front yard must be soft landscaping and 30% of the rear yard landscaped.
- Provincial rules: Ontario Regulation 462/24 overrides some municipal limits for additional units, including lot coverage and separation distances. Ask city staff how it applies to your lot before you design around a number.
Approvals and fees
- Zoning (occupancy) certificate: required for every ADU except a duplex, before the building permit. The 2026 fee is $348, and staff aim to review it within 15 business days.
- Building permit: always required, plus an Electrical Safety Authority permit for the electrical work.
- Minor variance: if the design does not meet a rule above, the Committee of Adjustment can grant a variance. The 2026 fee is $1,800 for four or fewer units.
- Addressing: a backyard unit that does not face the street usually needs an addressing sign so emergency services can find it.
Our permit guide covers who can draw the plans and how inspections work.
Development charges and the ADU Grant
Ontario exempts a second unit, and a third unit including one in a backyard building, from development charges, although school board charges can still apply. Kitchener's ADU Grant, which opened January 19, 2026 on a first-come basis while funding lasts, covers 100% of the school board charges on a second and third unit, and backyard units qualify. For a fourth unit it covers 50% of all development charges, rising to 100% with a commitment to one affordable unit for five years, two energy-efficiency measures or one barrier-free unit. The building permit must be issued on or after January 5, 2026. Confirm funding is still available before you count on it.
Backyard home, addition or basement unit?
- A backyard home gives the most separation and privacy, but it needs its own foundation, services run from the house across the yard, and enough lot width and depth.
- An addition keeps everything under one roof and can house a main-floor suite for a parent. It has to meet the rear and side yard setbacks for the house itself. See our guide to planning an addition.
- A basement unit uses space you already have and is often the simplest route in a bungalow with a side entrance. See our basement apartment guide.
Waterloo: coach houses
Waterloo calls a backyard home a coach house. Under Zoning By-law 2018-050, as amended in December 2024:
- One coach house per lot, with up to two units, and no more than three additional units on the lot in total.
- Height up to 6.0 m (in the MacGregor-Albert RC1 zone, no taller than the existing house).
- Rear setback 0.6 m, or 1.2 m if the building is over 4.5 m tall; side setback 1.2 m. Not allowed in the front yard.
- A 1.1 m walkway from the front or corner-side yard, municipal water and sewer, and a slab or foundation: portable garden suites are not permitted.
- Parking: two spaces in total for a lot with two or three units, three for four units.
- The city recommends getting a letter of compliance as well as the building permit. Its ARU Grant covers up to 50% of costs, to a maximum of $30,000, for a detached unit rented at an affordable rate for at least five years.
Cambridge
Cambridge allows up to three units on a lot with a detached house, semi or townhouse: up to two in the house plus one in a backyard building, or all three in the house. The size, height and setback rules for the backyard building are in section 4.19 of Zoning By-law 26-007, in effect since February 3, 2026, and some areas are still under the older By-law 150-85, so confirm the numbers for your lot with the city's planning staff. The City and Region do not charge development charges on these units; school boards may. The city lists a one-time ARU grant of up to $10,000.
Thinking about a backyard home?
The first question is always the lot: width, depth, where the services run and what the zoning allows. We check those at the free site visit, and if a backyard home is not the best fit, we can talk through an addition or a basement unit instead. See our home additions in Kitchener and basement renovations in Kitchener, or the Kitchener page for everything we do in the city.
