The $5,000 shows up at the end of the process. Under the new plan, Clarington pays the grant only after the building inspector issues an occupancy permit for the unit and the owner submits a complete application. The program starts January 1, 2027. Applications deemed complete by December 31, 2026 are still handled under the old plans, which had no named grant for additional dwelling units. So a Bowmanville homeowner finishing a basement suite this fall is building on one side of a policy line while the grant sits on the other.
The timing matters less than what the money buys. Clarington is paying a flat amount for a five-year affordability promise on units the market was already producing quickly. That promise is measured against the tenant household's income, not a fixed rent ceiling. The fund also runs out at a number you can calculate.
How the Grant Lines Up With the Build
Council adopted the new Community Improvement Plan at a special meeting on August 10, 2026. It replaces the separate downtown improvement areas in Courtice, Bowmanville, Newcastle and Orono with one project area covering the whole municipality. The ADU grant is Program 6 in the adopted plan. Its eligibility checklist runs in roughly the same order as the build:
- The property is in Clarington, is serviced, and is zoned to allow an ADU.
- Any required agency approvals are in hand. The plan gives the Conservation Authority and the Durham Health Department as examples.
- The owner gets a new ADU building permit.
- The unit passes inspection and receives an occupancy permit.
- The owner submits the grant application and signs an attestation to keep the unit affordable for five years.
The plan defines "new" narrowly. The unit has to be getting its first building permit approval and be counted as a new housing start in Clarington. That covers a new unit inside an existing house, a new unit in an accessory structure, and a new unit in a new dwelling on a new or existing lot. The plan also explains why it's a grant rather than a fee break. Under the Building Code Act, building permit fees have to be collected on a cost-recovery basis and can't be waived.
Clarington's ADU page adds a detail that simplifies the paperwork. Once the inspector grants occupancy, the unit counts as registered with the Municipality, and the page describes no separate registration step. The occupancy permit is both the registration milestone and the grant trigger.
Why Clarington Is Paying for Suites
The answer is in the rental stock. Clarington's June 2025 Housing Needs Assessment counted 832 primary rental units across the municipality. It found that renter households have grown much faster than purpose-built rentals since 2011. The all-unit vacancy rate in 2023 was 0.2%, with one-bedroom units at 0.0%.
Secondary suites have been filling much of that gap. The same assessment reports 96 ADU building permits in Clarington in 2024, up from 11 in 2015. Across the region, Durham's 2025 Annual Building Activity Review, dated July 24, 2026, counted 1,004 additional residential units in 2025. In a market where a basement suite is often the only vacancy available, a small grant aimed at that supply reaches far more units per dollar than a rental tower.
What "Affordable" Means for an ADU
The plan uses two definitions of affordability. Most programs follow the provincial Affordable Residential Units bulletin under the Development Charges Act. The ADU program has its own definition:
"Affordable (for the purposes of Affordable Accessory Dwelling Units (ADUs)) means rental accommodation that costs less than 30% of a household's before-tax income (CMHC)."
That's a ratio, not a dollar ceiling. Whether a given rent passes depends on who is renting the unit. Current rent figures show the scale involved.
| Measure | 1-bedroom | 2-bedroom |
|---|---|---|
| CMHC average rent, Clarington zone, October 2025 | $1,608 | $1,788 |
| CMHC average rent, Oshawa CMA, October 2025 | $1,586 | $1,762 |
| Average asking rent, Oshawa listings, September 2026 | $1,684 | $2,040 |
| Median asking rent, Oshawa listings, September 2026 | $1,662 | $2,000 |
The CMHC figures come from its October 2025 rental market survey of purpose-built units. The September 2026 numbers are asking rents from Oshawa listings. They measure different things and shouldn't be read as one trend line. CMHC's secondary-market survey doesn't publish a basement-suite rent for Oshawa.
Here is how the 30% ratio works out. A one-bedroom renting at the September 2026 Oshawa average of $1,684 costs $20,208 a year, which is under 30% of income for a household earning more than about $67,400. A two-bedroom at the $2,040 average asking rent costs $24,480 a year, which corresponds to a household income above about $81,600. At the CMHC Clarington-zone two-bedroom average of $1,788, the threshold is about $71,500.
Under the CMHC definition, the same suite at the same rent can count as affordable for one tenant and not for another. The plan's text doesn't say how the attestation will be checked over the five years. The staff report says administrative details, a standardized application form and a scoring and evaluation framework are still being finalized before launch.
How the ADU Promise Compares to the Rental-Building Stream
Program 7, the plan's stream for purpose-built affordable rentals, shows how light the ADU terms are. Program 7 applies to buildings with four or more rental units and can reimburse up to 80% of the municipal property-tax increase for up to 10 years. In exchange, owners sign a binding agreement registered on title, provide yearly evidence that units remain affordable, and keep them affordable for at least 25 years.
The ADU grant asks for a signed attestation covering five years. Program 6 doesn't list an owner-occupancy requirement. The difference fits the scale: a five-year promise on one suite for a one-time $5,000, set against a 25-year commitment on a building for a decade of tax relief. The plan sets terms a homeowner with one basement can realistically meet.
The Fund Has a Ceiling
The staff report sets aside $2 million in developer-funded contributions, moved from Clarington's Affordable Housing Reserve Fund, for the ADU program alone. It's part of about $3 million for the whole plan. At $5,000 a unit, $2 million covers 400 grants. At the 2024 pace of 96 ADU permits, that's about four years of Clarington's suite construction, assuming every permit qualifies and applies.
The plan doesn't say what happens when the fund runs low. It also doesn't publish how the scoring framework will treat ADU applications. Those details sit with staff ahead of the January launch.
The Lot Decides Eligibility First
The grant requires zoning that allows an ADU, so Clarington's ADU rules come before anything else. The guide allows up to two ADUs on a property. In Bowmanville and other areas shown green on the municipal map, that means one unit in a detached, semi-detached or townhouse dwelling and one in an accessory building, for up to three units including the main home. Some map designations, including Natural Core, Natural Linkage and Environmental Protection lands, don't allow ADUs. Oak Ridges Moraine and Greenbelt areas have narrower rules.
The site standards are often where the plan for a specific lot gets decided:
- Two existing parking spaces on the property, plus one more space for each ADU
- At least 30% of the front yard kept as landscaped open space
- A detached ADU smaller in floor area than the main house
- Rear and interior side setbacks of at least 1.8 metres for accessory structures
- Lot coverage for the accessory building capped at 10% of the lot or the zone maximum, whichever is less
- A height limit of 5.25 metres in urban residential zones and 6.5 metres in agricultural or rural residential zones
Parking and front-yard landscaping can work against each other on a narrow lot. Every added parking space takes front-yard area that counts toward the 30% minimum.
Development charges are another cost item. The Development Charges Act exempts qualifying second and third units in detached, semi-detached and row houses, plus one qualifying unit in an ancillary building. Clarington's development charges page notes that Durham Region and school boards levy their own charges. Building permit fees still apply.
Frequently Asked Questions
Did the old Bowmanville improvement plan have an ADU grant? Not under that name. The 2018 Bowmanville plan included a general Building Permit Fee Grant of up to $3,000 alongside heritage façade, signage and accessibility grants. It applied within a defined downtown area, and its text doesn't say whether residential suites qualified.
Is a basement suite the only kind of unit that qualifies? No. The plan's definition of "new" includes units in accessory structures and units in new dwellings, as long as the unit is getting its first building permit approval and counts as a new housing start.
Where are the final application details posted? The Municipality keeps the adopted plan at Clarington Connected, and the staff report says an updated CIP webpage will launch with the program.
A finished, permitted second unit changes how a Bowmanville house is valued and how it's marketed, whether or not the owner applies for the grant. If you're weighing a suite before selling, or looking at a listing with one already built, McDougall Team can show you how comparable Clarington properties with legal second units have priced and leased. Get your free home valuation and we'll include the suite in the numbers.
This article is general information, not legal, tax or financial advice. Consult a qualified professional about your situation.
