Garden Suites in Kingston detached ARUs, the $40,000 loan, and the half-inch water pipe
Kingston calls a garden suite a detached ARU, and it has one of the richer incentive programs in Ontario. It also has a waitlist, a rent cap, and a hard date. Only projects with a building permit issued by December 1, 2026 are being considered for the current incentives.
At a glance
Rural properties are excluded from the ARU program. Check the zoning map for your lot.
Yes. Most urban properties in Kingston can add a detached ARU behind a single-detached, semi or townhouse, as long as its floor area does not exceed the main house and you provide one parking space (tandem is fine). Kingston will lend up to 50% of the cost or $40,000 as a forgivable loan if you rent at 90% of average market rent for five years.
We Don’t Build in Kingston. Here’s What We Do.
We build in Simcoe County and around Georgian Bay. Elsewhere, including Kingston, we sell lot reports, permit packages and builder calls. That means we have no reason to tell you your lot is perfect so we can sell you a building.
Everything below comes from the City of Kingston’s own pages, checked in October 2026. Kingston publishes more about money than about measurements, so where the setback or height is not on a current city page, we tell you which by-law to read instead of making one up.
ARU, SRU, Garden Suite
Kingston now says additional residential unit (ARU). Its older guides said second residential unit, and you will still see that phrase on some documents. The city defines an ARU as an independent dwelling unit in the same building or on the same property as a single-detached house, semi-detached house or townhouse.
A garden suite in Kingston’s language is something else: the city says an ARU is not permitted on a lot that already contains a garden suite, two or more dwelling units, a boarding house or a lodging house. So if you are shopping for a modular backyard unit, the word to use with the city is “detached ARU.” Our terms glossary lines up all the Ontario names.
The Published Rules, and the Gaps
| Rule | Kingston (as published) |
|---|---|
| Where allowed | Most properties with a single-detached, semi-detached or townhouse; not rural properties |
| Not allowed on | Lots with 2+ dwelling units, a garden suite, boarding or lodging house; lands subject to natural hazards; “Loughborough Lake” lands; “Sewer Capacity Limitations” lands |
| Size | ARU gross floor area equal to or less than the principal dwelling (open porches, balconies and attached garages excluded) |
| Height and setbacks | Not on the current city ARU pages; check Zoning By-law 2022-62 for your zone. The city’s 2019 guide required 1.2 m from rear and interior side lines and the accessory height limit of the zone |
| Location | 2019 guide: rear or interior side yard only, not the front or exterior side yard |
| Parking | At least 1 space, tandem allowed |
| Access | Safe entrance and exit per the Building Code |
| Servicing | Holding symbol must be lifted in “Water Supply/Water Quantity” and “Servicing Capacity (Cana Subdivision)” areas |
| Self-contained | Pre-reviewed designs page: own washroom, kitchen, laundry and sleeping space |
Last checked October 2026 · Source: City of Kingston ARUs; Second Residential Unit guide (Sept 2019)
The 2019 guide is old. Kingston passed a new city-wide Zoning By-law (2022-62) after that guide was written, and Ontario added O. Reg. 462/24 in November 2024, which allows up to 45% lot coverage on lots with additional units and caps required separation from the house at 4.0 m. Use the 2019 numbers as a starting point only.
Six Steps Through DASH
Kingston takes ARU permits online through its DASH portal. Fees are not listed on the ARU page; the city emails them when your application is accepted.
1. Confirm zoning and constraints
Use the city’s zoning by-law map. Look for holding symbols, sewer surcharging areas, Loughborough Lake lands and hazard lands. Any of those can stop the project or force a rezoning.
2. If you want the incentive, line it up now
The incentive requires an ARU building permit first, then an application through MyKingston. Applications after completion are refused. With a December 1, 2026 permit cutoff, the clock matters more than the floor plan.
3. Prepare the drawings
Kingston lists: plot plan, floor plan, elevations and cross section, spatial separation calculations, mechanical design, energy efficiency design summary form, Schedule 1 designer form, and foundation engineering where needed.
4. Apply in DASH
Upload the drawings, wait for an email confirming acceptance and your fees, and pay. A building official issues the permit within 10 business days or asks for more information.
5. Inspections
Book through DASH with at least 24 hours’ notice. The city assigns the new unit number during permitting and zoning review.
6. Rent it right
You are now a landlord under the Residential Tenancies Act and Kingston’s Property Standards By-law. Snow, yard and repairs are on you.
Last checked October 2026 · Source: City of Kingston ARU Permits
Usually Zero, Ask Anyway
Ontario’s Development Charges Act exempts a second and third unit on a lot with a house, including one in an ancillary building. Kingston’s current ARU pages do not publish a separate DC figure, and its 2019 guide referred to “impost and development fees” under the fees by-law.
So: expect the statutory exemption, and ask Building Services to confirm in writing what, if anything, applies to your lot before you sign a contract. Our DC explainer covers the province-wide rules.
Up to $40,000, Plus Three Smaller Grants
| Program | Amount | Key terms |
|---|---|---|
| Detached ARU Incentive | Lesser of 50% of project cost or $40,000 | Forgivable loan paid after occupancy; rent at or below 90% of average market rent for 5 years |
| Interior ARU Incentive | Lesser of 50% or $30,000 | Same terms |
| Accessibility ARU Grant | $5,000 | Six features: 900 mm clear doors, 1100 mm halls, bathroom grab bars, accessible shower, controls at 1200 mm, knee space at the kitchen sink. Stackable or stand-alone |
| Rough-In Detached ARU Grant | $5,000 | Rough in water, sewer and electrical for a future detached ARU under permit. Cannot be combined with any other incentive |
| Servicing Constraint Area Grant | Lesser of 50% or $10,000 | Upgrade an existing half-inch water service; must pair with the Detached or Interior incentive |
| 2026 limits | Bachelor | 1 bed | 2 bed | 3 bed |
|---|---|---|---|---|
| Max rent incl. utilities | $1,082 | $1,353 | $1,588 | $1,804 |
| Max tenant household income | $43,000 | $55,000 | $64,000 | $65,000 |
Last checked October 2026 · Source: City of Kingston ARU Incentive Programs
Status: waitlist. Kingston is placing applications on a waitlist. Only projects with a building permit issued by December 1, 2026 will be considered, and being waitlisted does not guarantee funding. The building permit must be issued after August 13, 2024, one ARU per property, and taxes and mortgage must be current.
The fine print is fair, but read it. Forgiveness accrues at 20% per year. Stop renting under the terms early and you repay the balance pro rata. Loans of $5,000 or more are secured by a second mortgage on title, which your lender will want to know about. After conditional approval you have one year to finish and rent the unit.
A unit for your mother does not fit a rent-capped tenant program. For family builds, look at the multigenerational tax credit and our aging parents guide. For everything else, see the funding directory.
Five Designs, Building Code Only
Kingston lists five pre-reviewed detached ARU designs from three builders: a studio, one-bedroom and two-bedroom pod from one, a studio from another, and one design from a third. City building staff have checked them for Building Code compliance. Sizes and prices are not posted; you contact the vendor, and every agreement is between you and them.
The city is blunt about the limit: having plans pre-reviewed for the Building Code “does not mean they meet the Zoning Bylaw,” and you still submit a full ARU permit application. Your setbacks, your servicing and your site plan are still yours to sort out.
Picked a pre-reviewed pod?
Our Prefab/Kit Permit Pack covers the foundation interface, site plan and HVAC design the city still needs. Send the model and your survey for a fixed quote.
Last checked October 2026 · Source: City of Kingston Pre-Reviewed Detached ARUs
Kingston’s Real Constraint Is Underground
The half-inch water service
Kingston built a whole grant around upgrading existing half-inch water services, which tells you how common they are. Two households on a half-inch line means weak showers in both. Budget for a new service from the main if your house has one.
Sewer surcharging areas
The city does not allow ARUs in cellars or basements in “Sewer Surcharging” areas, including combined storm and sewer systems. If your backyard design includes a basement, check this first.
Holding symbols
In the Water Supply/Water Quantity and Cana Subdivision servicing areas, you apply to lift a holding symbol before you can build. That is a planning application, with its own fee and timeline.
Frost cover on the lines
The city’s 2019 guide called for 1200 mm of frost protection cover on services extended to the unit. Long trenches across a rocky Kingston yard get expensive fast; get a site visit before you price the building.
Our servicing cost guide covers trenching, laterals and electrical service upgrades. For heat loss and mechanical design the city will accept, see OntarioHeatLoss.ca.
Outside the Urban Boundary It Is a Different Conversation
Kingston says most properties qualify for an ARU, “except rural properties.” If you are in the rural part of the city, or in a neighbouring township like Loyalist, South Frontenac or Frontenac Islands, ask the planning department whether a temporary use garden suite is possible instead. Under the Planning Act those by-laws can run up to 20 years with extensions; see our temporary garden suite guide.
Rural means septic. A second unit adds flow your existing bed may not handle. Septic design goes through SepticReplacement.ca, and our rural and septic hub explains what the inspector checks.
Six Kingston Mistakes
- Missing the December 1, 2026 permit date. Drawings, review and resubmissions take weeks. If the incentive matters, start now.
- Building first, applying later. The city does not consider applications after completion.
- Taking the rough-in grant and the big loan. The $5,000 rough-in grant cannot be combined with anything else. Pick one path.
- Treating a pre-reviewed plan as a permit. Building Code review only. Zoning is still checked on your lot.
- Ignoring the second mortgage. Loans of $5,000 or more go on title. Tell your lender before, not after.
- Assuming last year’s rent cap. Caps and income limits are set each year. Use the 2026 numbers above, then check again before you sign a lease.
Want your lot checked before December? The $399 + HST Feasibility Report comes back in 48 hours and is credited toward permit plans or a build.
Beat the December permit date with a plan that holds up
Zoning, servicing route, incentive fit and a realistic budget for your Kingston lot, in 48 hours.
Kingston Garden Suite Questions
Can I build a garden suite in Kingston?
On most urban lots, yes, as a detached ARU (additional residential unit). The main house must be a single-detached, semi-detached or townhouse, and the lot cannot already have two or more units, a garden suite, or a boarding or lodging house. Rural properties, hazard lands and some servicing-constrained areas are excluded.
How big can a detached ARU be in Kingston?
Kingston says the ARU’s gross floor area can be equal to or less than the principal dwelling. Open porches, balconies and attached garages are not counted. Height and setbacks come from Zoning By-law 2022-62 for your zone, so check the zoning map or ask Building Services before you design.
How much is the Kingston ARU incentive?
The Detached ARU Incentive is a forgivable loan of 50% of project cost or $40,000, whichever is less. You can add a $5,000 accessibility grant and, on constrained lots, up to $10,000 for a water service upgrade. You must rent at or below 90% of average market rent for five years.
What is the deadline for the Kingston ARU incentive?
Kingston is waitlisting applications and says only projects with a building permit issued by December 1, 2026 will be considered. Waitlisting does not guarantee funding. The permit must also have been issued after August 13, 2024.
Does Kingston have pre-approved garden suite plans?
Kingston lists five pre-reviewed detached ARU designs from three builders, checked by city staff for Building Code compliance. They are not zoning approvals. You still submit a full ARU building permit application and your lot is checked for zoning.
How long does a Kingston ARU permit take?
Kingston says a building official issues the permit within 10 business days of an accepted application, or asks for more information. Incomplete drawings restart the wait, so a full package with spatial separation and mechanical design saves time.
Do I pay development charges on a Kingston garden suite?
Ontario law exempts a second and third unit on a residential lot from development charges, including one in an ancillary building. Kingston does not publish a separate ARU figure on its current pages, so confirm with Building Services before you budget.
Will you build my garden suite in Kingston?
No. We build in Simcoe County and Georgian Bay only. In Kingston we offer the $399 + HST Feasibility Report, permit packages and paid builder calls so you can hire a local builder with a clear scope.