Garden Suites in Windsor-Essex Windsor ADUs, Lakeshore and the county towns
Windsor lets a backyard ADU go up to 8 m tall with a pitched roof, which is generous by Ontario standards, but never taller than the house. Lakeshore caps a detached unit at 120 m² and 6.5 m. We found no city grant for a new ADU in Windsor in October 2026, so budget as if there isn’t one.
At a glance
Flood-prone and ERCA-regulated lots need extra approvals. Check the map first.
Yes. Windsor allows three units on an urban lot, with one in a detached building. It must sit 1.2 m from side and rear lot lines, top out at 8 m with a roof of 20 degrees or more (6 m if flatter), never exceed the house height, and connect to municipal sewer, storm and water. One extra parking space is needed outside the core.
Four-Plus Hours From Our Yard. So We Plan, We Don’t Build.
We build in Simcoe County and Georgian Bay. In Windsor-Essex we sell lot reports, permit packages and builder calls. That keeps us honest: we gain nothing by telling you a lot works when it doesn’t.
Below is what the City of Windsor and the Town of Lakeshore publish, checked October 2026. The other county towns get a short section, because their pages publish less. Where a number is not published, we tell you where to look.
Windsor Says ADU. Lakeshore Says ARU.
Windsor uses additional dwelling unit (ADU). A backyard unit is an ADU in a detached accessory building. Windsor also says “tiny homes” are not a defined term: a small backyard home is just a detached ADU, and motor homes, RVs and trailers cannot be used as dwelling units. So no, the park model trailer behind the garage does not count.
Lakeshore uses additional residential unit (ARU), with a separate “agricultural ARU” for farm zones. See our terms glossary and the garden suite vs bunkie vs tiny home guide.
Windsor and Lakeshore Side by Side
| Rule | City of Windsor | Town of Lakeshore (residential zones) |
|---|---|---|
| Units per lot | 3 total: up to 3 in the house, or 2 in the house + 1 detached | Up to 3 as of right per the ARU page; OPA 22 (four units, fully serviced areas) passed November 4, 2025, sent to the County for approval |
| Size | Not published on the city page; see Zoning By-law 8600, s. 5.99.80 | Max 50% of the house, up to 120 m² GFA (agricultural ARU up to 140 m²) |
| Height | 8 m with a roof slope of 20° (about 4/12) or more; 6 m if flatter (minor variance can allow 8 m); never taller than the house | 6.5 m and not taller than the house (agricultural 7.5 m) |
| Side / rear setback | 1.2 m | 1.5 m (rear: or the conservation authority setback); 3 m if a two-storey unit has a window facing the line |
| Distance from the house | Not published | No closer than 3 m, no farther than 50 m |
| Lot coverage | Not published | Per the zone (agricultural 30%) |
| Parking | 1 extra space for the ADU, except in mapped core areas; a second ADU needs none | 1 extra space per unit, plus 2 for the house; 3 m x 6 m |
| Access | Direct pedestrian access from street or alley without passing through the main unit; visible address | Not published |
| Servicing | Paved public street, municipal sanitary, storm outlet, water and electrical | One service for house and ARU, one water meter; septic review or new or expanded system on septic lots |
| Severance | Not allowed | Not allowed |
Last checked October 2026 · Source: City of Windsor Additional Dwelling Units; Town of Lakeshore ARUs; Lakeshore OPA 22 notice
One Windsor detail that catches people: converting an existing garage. The 1.2 m setback only applies to the part you alter, which can make an old garage close to the line a workable start. Our garage conversion guide covers the fire separation and foundation questions that come with it.
Windsor has also proposed a housekeeping amendment (files Z-016/23 and OPA 172) that removes minimum unit sizes from the ADU rules. The city page does not give an adoption date, so confirm its status before you design something very small.
How a Windsor ADU Gets Approved
1. Check the ERCA map and heritage list
Windsor links the Essex Region Conservation Authority regulated area map from its ADU page. If you are on the Municipal Heritage Register or in a heritage area, you cannot make an exterior change visible from the street to add an ADU.
2. Check the parking-exempt map
Older core areas with smaller lots and good transit do not need the extra space. Everywhere else, find room for one more car without blocking the access path.
3. Drawings that show the separation
Windsor says Part 9 of the Building Code applies (sections 9.4 to 9.33: structure, egress, fire protection, plumbing, ventilation, heating) and the plans must show a distinct physical separation between units. Lakeshore wants an Ontario Land Surveyor-sealed grading plan and an Energy Efficiency Design Summary for new detached ARUs.
4. Apply and pay
Neither Windsor nor Lakeshore posts ADU fee amounts on these pages. Lakeshore lists a building permit fee per square foot of living space, a plumbing fee per washroom, a refundable indemnity deposit and a Green 911 sign where needed, and says fees are subject to change.
5. Minor variance if you need it
Flat roof over 6 m in Windsor, or an odd lot? That is a Committee of Adjustment application. Our minor variance guide explains cost, timeline and how to win one.
6. Inspections, address, occupancy
Windsor requires a clearly visible municipal address for the unit. Units created before November 20, 2018 are not grandfathered, so an old unpermitted backyard unit needs a permit now.
Last checked October 2026 · Source: City of Windsor Additional Dwelling Units; Town of Lakeshore ARUs
No DCs, No Grant Found Either
Ontario’s Development Charges Act exempts a second and third unit on a residential lot, including one in an ancillary building. Lakeshore states it directly: “ARUs are not subject to development charges,” though building fees still apply. Windsor’s ADU page does not address DCs, so confirm with the Building Division.
Incentives: we did not find a current City of Windsor or County program that pays for a new backyard ADU as of October 2026. Windsor does run a Basement Flooding Protection Subsidy Program, which matters if your connection work touches the house plumbing, and links it from the ADU page. Federal programs and tax credits are listed in our grants directory.
Building for a parent? The federal multigenerational home renovation tax credit may be the only money on the table, and it does not cap your rent because there is no rent.
Know your Windsor-Essex lot before you spend on drawings
Setbacks, height, ERCA flags, parking, servicing route and a realistic full-project budget, in writing in 48 hours. Credited toward permit plans.
None Published Locally
Neither Windsor nor Lakeshore lists pre-approved ADU plans on its ADU page. The federal CMHC Housing Design Catalogue has free ADU designs you can start from, but a designer still has to adapt them to your lot, add the foundation and site plan, and do heat loss calcs. Our roundup of pre-approved plans in Ontario shows which cities have them and what they leave out.
If you are buying a prefab or kit, ask where the package stops. Foundation, crane, servicing and the permit drawings for the site are usually yours. Our garden suite kits guide has the checklist, and our permit packages fill the gap.
Flat Ground, Wet Basements, Old Laterals
Sewer and storm, both
Windsor requires access to a municipal sanitary sewer and a municipal storm water outlet. Roof water from the new unit has to go somewhere legal, not into your neighbour’s yard. Windsor also points owners to downspout disconnection and backflow prevention.
Flat lots and gravity
Much of Windsor-Essex is very flat. Draining a backyard unit by gravity to an existing lateral can leave very little slope to work with. Get elevations shot before you set the floor height.
One service in Lakeshore
Lakeshore allows one service and one water meter for the house and ARU together. Everything tees off the house, so the existing line has to be big enough.
Septic in the county
On septic lots, Lakeshore gives three options: a septic review by a licensed installer, a new system for both units, or replacing or expanding the current one (both of the last two need a permit). Septic design runs through SepticReplacement.ca.
More on trenching, laterals and hydro in our servicing cost guide. Heat loss and HVAC design for permits: OntarioHeatLoss.ca.
LaSalle, Tecumseh, Amherstburg, Essex, Kingsville, Leamington
Essex County has seven member towns, Lakeshore included. All of them sit under the same provincial baseline: a house plus up to two additional units on serviced urban lots, the DC exemption, and O. Reg. 462/24, which allows up to 45% lot coverage on lots with additional units and caps the separation a town can require from the house at 4.0 m.
Heights, setbacks and sizes still vary by town. We did not find homeowner ADU guides with numbers for LaSalle, Tecumseh, Amherstburg, Essex, Kingsville or Leamington, so call the planning department and ask for the ARU section of the zoning by-law. Bring your lot survey. On farm and hamlet lots, expect septic, well and Minimum Distance Separation questions; our farm garden suite guide and rural and septic hub explain them.
Six Windsor-Essex Mistakes
- Building taller than the house. Windsor allows 8 m, but never higher than your bungalow. If your house is 5.5 m, so is your limit.
- Choosing a flat roof and expecting 8 m. Under a 20° slope the limit is 6 m unless you win a minor variance.
- Putting a trailer or RV in the yard. Windsor says they cannot be used as dwelling units.
- Assuming an old backyard unit is grandfathered. Windsor says units created before November 20, 2018 are not.
- Forgetting the second parking space. Outside the mapped core areas, the ADU needs one more space.
- Skipping the ERCA check. Flood-regulated land can block the location or add a permit and conditions.
Got a builder quote already? A 60-minute quote review is $249.99 + HST and shows you what is missing before you sign.
Find out what your Windsor-Essex lot will take
Height, setbacks, parking, flood flags and the servicing route, checked against your survey in 48 hours.
Windsor-Essex Garden Suite Questions
Can I build a garden suite in Windsor?
Yes, as a detached ADU. Windsor allows three units on an urban lot with a single-detached, semi-detached, street townhouse or duplex: two in the main building plus one in a detached accessory building. The lot must have a paved public street and municipal sanitary, storm, water and electrical services.
How tall can a backyard ADU be in Windsor?
Up to 8 m if the roof slope is 20 degrees (about a 4/12 pitch) or more, and 6 m if the roof is flatter. A low-slope or flat roof can go to 8 m through a minor variance. In every case the ADU cannot be taller than the main building on the lot.
What are the setbacks for an ADU in Windsor?
Windsor requires minimum side and rear setbacks of 1.2 m. When an existing garage is upgraded to include an ADU, the setback applies only to the part being altered. Heritage properties cannot make street-visible exterior changes to add an ADU.
Do I need extra parking for an ADU in Windsor?
One additional space is required for an ADU, except in older core areas with smaller lots that are well served by transit, which are shown on a city map. A second ADU on the same lot does not need another space.
Can I live in a tiny home or trailer in my Windsor backyard?
A small permanent backyard home is treated as a detached ADU and needs a building permit like any other. Windsor says motor homes, recreational vehicles and trailers may not be used as dwelling units.
How big can a detached ARU be in Lakeshore?
Lakeshore says a detached ARU cannot be more than 50% of the main house, up to a maximum of 120 m2 of gross floor area, or 140 m2 for an agricultural ARU. Height is 6.5 m and not taller than the house. It must be within 50 m of the house and no closer than 3 m.
Are there grants for a garden suite in Windsor-Essex?
We did not find a current municipal grant for building a new ADU in Windsor or Essex County as of October 2026. Development charges are exempt for a second and third unit under provincial law. Federal programs and the multigenerational tax credit may apply; see our grants directory.
Will you build my garden suite in Windsor?
No. We build in Simcoe County and Georgian Bay. In Windsor-Essex we sell the $399 + HST Feasibility Report, permit packages and paid builder calls, so you can hire a local builder with a clear scope and budget.