Bill 23 changed what you’re allowed to build on most Halton residential lots, and most homeowners still don’t know. If your backyard could fit a garage, it can probably fit a self-contained 1- or 2-bedroom rental that generates $1,800-$2,500 a month. Here’s the full 2026 playbook on garden suites in Milton, Oakville, Burlington, and Halton Hills.
What Bill 23 actually changed (and why your neighbour just got a permit)
Ontario’s More Homes Built Faster Act, 2022 (commonly known as Bill 23) fundamentally rewrote what residential property owners can build on their own lots. Since 2023, every Ontario municipality has been required to permit up to three residential units on most properties without rezoning.
In practice, that means a single typical Halton lot connected to municipal water and sewer can now legally contain:
- The main house
- An interior secondary suite, most often a basement apartment
- A detached accessory dwelling unit, known as a garden suite, laneway house, or backyard suite
The phrase to remember is “as-of-right“, meaning you don’t need a costly zoning amendment, you don’t go to council, you don’t fight a public hearing. You go to your municipality’s building department with proper drawings, you get a building permit, you build. The application path is the same as any major renovation.
For a Halton homeowner sitting on a 50-foot lot with a 25-foot-deep backyard, this is one of the most significant legal changes to residential property rights in a generation. And in 2026, three years after it took effect, the application volumes in Oakville, Burlington, and Milton are finally surging as homeowners catch up to what’s possible.
What does a garden suite cost to build in Halton in 2026?
For a properly engineered, code-compliant detached garden suite in the Halton/GTA market, expect the all-in cost to land between:
- 1-bedroom, ~500-600 sq ft: $200,000 – $280,000
- 2-bedroom, ~700-900 sq ft: $280,000 – $400,000
- Larger/custom 1,000+ sq ft: $400,000 – $550,000
The current 2026 benchmark for standard construction in the GTA sits in the $250 to $350 per square foot range, with premium finishes pushing closer to $450/sq ft.
That “all-in” cost includes the items most homeowners forget on first pass:
- Architectural and structural drawings: $4,000 – $10,000
- Building permit and inspection fees: $2,500 – $8,000 depending on municipality
- Servicing, running new water, sewer, electrical, and gas lines from the main house: $20,000 – $45,000 (varies enormously based on distance and obstacles)
- Foundation and slab
- Framing, insulation, drywall, finishes
- Full kitchen and bathroom
- HVAC (typically a separate mini-split or heat pump system)
- Landscaping and walkway restoration after construction
- HST on construction (though some homeowner rebates may apply)
The Bill 23 development charge bonus you shouldn’t miss
One of the underrated wins inside Bill 23: most qualifying garden-suite ADUs are now exempt from municipal development charges, which historically added $10,000 to $30,000 to the total project cost in Halton municipalities. This exemption alone shortens the typical rental payback timeline by roughly 12-18 months.
What can you actually charge in rent? Halton numbers by city
Based on May 2026 rental listings on Rentals.ca and similar platforms for self-contained, brand-new 1 and 2-bedroom suites in Halton:
- Oakville (south, central): $2,200 – $2,800/month for a 2-bedroom, $1,800 – $2,300/month for a 1-bedroom
- Oakville (north, near Sixteen Mile): $2,000 – $2,500/month
- Burlington (Aldershot, Tyandaga, Roseland): $1,950 – $2,500/month for a 2-bedroom
- Milton: $1,800 – $2,300/month for a 2-bedroom, strong demand from commuters who want lower-cost detached-style living close to the GO line
- Halton Hills (Georgetown, Acton): $1,600 – $2,100/month, with steady demand from local families and tradespeople
That puts a typical Halton garden suite in the $22,000 to $33,000 annual gross rent range. After property taxes, insurance increase, utilities (if landlord-paid), and maintenance reserve, you’re typically netting $14,000 to $24,000 per year.
On a $280,000 build cost, that’s a 5-9% net annual yield on the construction investment, and that’s before any appreciation in the underlying property value, which I’ll get to in a moment.
The three highest-ROI use cases I see in Halton right now
1. Pure rental income (the investor play)
This is the most common use case, and it’s where the math is clearest. A Halton homeowner with stable employment, decent home equity, and a usable backyard borrows against their home equity (HELOC or refinance), funds a garden suite, and adds $1,800-$2,500 in monthly rental income.
If the homeowner is also facing a 2026 mortgage renewal payment shock, this strategy can effectively absorb most or all of the new monthly payment increase. It’s why I’m seeing a sharp uptick in dual-conversation appointments, homeowners asking about both garden suite feasibility and renewal strategy in the same meeting.
2. Multi-generational housing (the family play)
With average detached prices in Oakville and Burlington still above $1.3M and average Halton condo prices climbing, more families are choosing to bring aging parents on-site rather than send them to a retirement residence at $5,000-$7,000 per month. A garden suite provides privacy and independence for the parents, while keeping them close enough for daily help and grandchildren contact.
The 2026 tax wrinkle worth flagging: there are now federal multigenerational home renovation tax credits available for qualifying ADU construction that houses a senior or qualifying adult relative, up to 15% of qualifying expenses to a maximum credit of $7,500. Speak with your accountant about eligibility before construction.
3. Work-from-home space + future rental option (the hybrid play)
A surprising number of clients are building garden suites first as a dedicated home office or studio, with the rental option in their back pocket for retirement years. This is especially common in Oakville and Burlington among self-employed professionals.
The bonus: a fully self-contained, separately-metered garden suite with a kitchen and bathroom is far more flexible than an attached home office, and the home retains far more market value at resale than a property where the office is built into the main living space.
The permitting timeline: what actually happens, in calendar weeks
Here is the realistic timeline for a Halton garden suite from “let’s do this” to “tenant moves in”:
- Weeks 1-2: Initial feasibility, measure your yard, confirm zoning and servicing capacity with municipality, get rough quotes from 2-3 design-build firms
- Weeks 3-8: Architectural drawings, structural engineering, site plan
- Weeks 9-18: Building permit review and approval (variable; current permit timelines should be confirmed directly with the municipality at the start of the project)
- Weeks 19-22: Site prep, excavation, servicing connections
- Weeks 23-38: Foundation, framing, mechanical, finishing, inspections
- Weeks 39-42: Final inspection, occupancy permit, listing for tenant
Realistic total: 9-10 months from first phone call to tenant key handover. Faster is possible with a turnkey modular ADU (some manufacturers can deliver in 6 months); slower is common when servicing is complex or when neighbours raise drainage concerns.
Does a garden suite increase my home’s resale value?
Yes, although the resale impact is rarely a 1 to 1 return on construction cost. Real estate professionals working with ADU-equipped properties commonly observe two value drivers at resale:
- A partial recovery of construction cost as immediate value uplift on resale, with the proportion varying by neighbourhood and finish level
- Plus additional capitalised value of the rental income stream, which investor buyers and appraisers tend to incorporate into their valuation. The exact multiple varies with cap rates in the local rental market at time of sale
The combined effect can be meaningful, but the specific dollar uplift depends on the same comparable sales work any home requires. Have your REALTOR prepare an ADU-specific CMA before committing to construction if resale value is part of your math.
The caveat: this math only works at resale if the suite is fully permitted, fully separately serviced, and shows well. A “shed conversion” built without permits is a liability at resale, not an asset. Pay for the permits. Pay for the proper drawings. The CRA and the buyer’s home inspector will both notice if you didn’t.
What can go wrong: the honest checklist
- Septic systems: If your home is not on municipal sewer (rare but possible in parts of Halton Hills), Bill 23 doesn’t automatically apply. Septic capacity must be confirmed.
- Heritage districts: Old Oakville, parts of Burlington’s downtown core, and parts of Georgetown have heritage overlays that may impose design constraints.
- Tree protection bylaws: All four Halton municipalities have meaningful tree-removal restrictions. A mature tree in the wrong place can force a redesign or significantly delay your permit.
- Setbacks and rear-yard coverage: The footprint of a garden suite is generally capped at the lesser of 40% of rear yard area or 60 square metres, and you need to maintain prescribed setbacks from the main house and lot lines.
- Drainage: Adding a hard-surface roof in your backyard changes how water runs across your lot. Most municipalities now require a drainage plan.
- Neighbour relations: Bill 23 took away neighbours’ ability to block your project through rezoning objections, but they can still complain about noise during construction, drainage issues afterwards, and bylaw matters. Talk to them early. A bottle of wine in advance is cheaper than a year of complaints later.
FAQ: Garden suites and ADUs in Halton 2026
Do I need rezoning to build a garden suite in Oakville, Milton, or Burlington?
Under Ontario’s Bill 23, most residential properties on municipal water and sewer are permitted to have up to three residential units as-of-right, meaning no rezoning application is required. You still need a building permit and must meet zoning standards for setbacks, height, lot coverage, and parking, but you don’t need to go through a public rezoning process.
How much rent can I get for a garden suite in Halton?
Self-contained 1-bedroom garden suites in Halton typically rent for $1,800-$2,300/month in 2026, and 2-bedroom suites range from $1,950-$2,800/month depending on city, neighbourhood, and finish level. Oakville south generally commands the highest rents; Halton Hills the most modest.
Are garden suites exempt from development charges in Ontario?
Yes, Bill 23 eliminated municipal development charges for most qualifying ADUs, which reduces total project costs by approximately $10,000-$30,000 in Halton municipalities.
Can I get a mortgage for a garden suite?
Most major lenders will allow homeowners to refinance their primary mortgage to extract equity for ADU construction, or to use a HELOC. There are also a growing number of specialized ADU construction loans. Speak with a mortgage broker about the best structure for your situation.
Does a garden suite affect my property tax assessment?
Yes. Adding a self-contained dwelling unit to your property typically increases your MPAC assessment and therefore your annual property tax. Budget approximately $1,200-$2,500/year in additional property tax depending on your municipality and the suite’s size and finish level.
How long does it take to build a garden suite in Halton?
From first design meeting to tenant move-in, expect 9-10 months on a typical Halton lot with no major complications. Permit review takes 2-4 months, and construction itself runs 4-5 months for a properly engineered, fully serviced unit.
Thinking about whether your Halton lot could support a garden suite, and what it would do to your home’s resale value? I work with homeowners across Milton, Oakville, Burlington, and Halton Hills on both the real estate side (lot suitability, resale impact, neighbour comps) and the introduction to vetted local design-build firms. Send me your address and I’ll send back a no-obligation Halton-specific feasibility note.
, Ashish Gupta, REALTOR®, CENTURY 21 GREEN REALTY INC., Brokerage
Serving Milton, Oakville, Burlington, and Halton Hills
This article is general real estate market commentary and is not financial, legal, construction, or zoning advice. Bill 23 implementation, municipal bylaws, building code requirements, lender policies, and tax rules vary by municipality and over time. Always confirm current rules with your local municipality, a licensed architect or designer, your mortgage broker, and your accountant before committing to construction. Real estate trademarks REALTOR®, REALTORS® and MLS® are controlled by The Canadian Real Estate Association (CREA). Ashish Gupta is a REALTOR® registered with the Real Estate Council of Ontario (RECO) and a Sales Representative with CENTURY 21 GREEN REALTY INC., Brokerage.