Home base. Permits from the lake to the escarpment.
We are based in Ancaster, so the City of Hamilton is the building department we know best. It reviews permits for the lower city, the Mountain, Ancaster, Dundas, Stoney Creek, Waterdown, Flamborough, Binbrook and Glanbrook. We prepare the drawings and take the application through to an issued permit.
- Covers
- Hamilton, Ancaster, Dundas, Stoney Creek, Waterdown, Flamborough, Binbrook, Glanbrook
- Conservation
- Hamilton Conservation Authority, Conservation Halton, Niagara Peninsula Conservation Authority, Grand River Conservation Authority
- ADU permit
- $515 inside a house, $1,030 detached
- Apply
- Online, through my.hamilton.ca
- From Ancaster
- Home base
One permit office, four conservation authorities.
The City of Hamilton reviews every permit here, but the rules around it change with the ground. Pick where the lot is and how it is serviced.
- 01Which community is the lot in?
- 02How is the lot serviced?
- Conservation authorityHamilton Conservation Authority, or Grand River Conservation Authority depending on the watershed.Likely
- Escarpment and NECMuch of old Ancaster sits on or near the escarpment and the Dundas Valley creeks, so check both the HCA map and the NEC map.Check
- Inside the houseA single detached house can hold up to 2 ADUs. A duplex can add 1, and a triplex can add a fourth unit.Allowed
- Detached ADU1 in the rear or interior side yard, up to 75 m² (or the house's floor area, if smaller) and 6.0 m tall.Allowed
- ServicingThe detached unit must connect through the main house. Separate services to the street are not permitted, and the water service may need upsizing.Note
- Also checkNew single detached houses (and new detached units) in the ER zone of the former Ancaster Zoning By-law 87-57 need a zoning compliance review before the permit.Overlay
A first read, not a ruling. Watershed lines do not follow community names, so the conservation authority and NEC maps decide for your address. Some lots also still sit under a former municipality’s zoning by-law.
Most work past paint and flooring needs a permit.
The City reviews each application against the Ontario Building Code, its zoning by-law, conservation authority and Niagara Escarpment Commission rules, and other applicable law. These come from the City’s own list.
| Work | Permit? |
|---|---|
| Additional dwelling unit | Yes, inside the house or detached, including a municipal address for the new unit. |
| Basement finishing and interior changes | Yes: finishing a basement, new rooms, moving or adding walls (load-bearing or not), new or larger door and window openings, new drywall and insulation. |
| Additions and structure | Yes: additions (including enclosing a porch), underpinning, structural repairs, a walkout basement, new or replaced weeping tile. |
| Decks | Yes for any deck attached to the house. A detached deck needs one once it is over 10 m² and more than 200 mm above grade (uncovered), or over 10 m² (covered). |
| Sheds and garages | Yes over 15 m², more than one storey, or with plumbing. Not under that, for a house, semi or row house. |
| Plumbing and ducts | Yes for new or moved plumbing, septic work, a wood stove or fireplace, and new or replaced ductwork. |
| No permit, per the City | Painting, millwork, cabinets and flooring; re-shingling with the same material; same-place plumbing fixtures; same-size windows where no fire rating applies; replacing a furnace; a fence that does not enclose a pool. |
Building without a permit can bring an order registered on title, a stop work order or fines of up to $50,000 for an individual on a first offence under the Building Code Act. Not sure where your project falls? Try do I need a permit?
Up to four units on most urban lots.
Hamilton calls a second unit an additional dwelling unit (ADU), and a backyard unit an ADU – Detached. Older by-law text calls them secondary dwelling units. A dedicated ADU team reviews permits for houses with up to two internal units and one detached unit; three or four units are reviewed separately as multi-residential.
| Rule | What the City allows |
|---|---|
| Units per lot (urban) | No more than 4 dwelling units on a lot with an ADU. A single detached house can hold up to 2 ADUs inside, plus 1 detached ADU. A duplex can add 1; a single, duplex or triplex can be converted to hold a fourth unit. |
| Semis and townhouses | Each unit may hold up to 2 ADUs. A detached ADU is not permitted where the semi or townhouse already holds 2 or more. |
| Rural zones (A1, A2, S1, P6) | 1 ADU in the house on a lot larger than 0.6 ha. 1 detached ADU with a single detached house on at least 1.5 ha. Not on lands shown in the by-law's Special Figures 24.1 to 24.5. |
| Servicing | A detached ADU must connect through the main house; separate services to the street are not permitted. The water service may need upsizing, and a water pipe sizing form goes with the permit. On septic, the system must carry the extra load or be upgraded. |
| Detached ADU size | Urban: up to 75 m² or the main house's floor area, whichever is less, and no more than 70% of the house's ground floor where that is 105 m² or less. Rural: up to the main house's floor area. |
| Height and coverage | 6.0 m maximum, with no balcony or rooftop patio above the first floor. Total lot coverage 45% (urban) or 25% for all accessory buildings (rural). |
| Placement | Rear or interior side yard only, 1.2 m from the side and rear lot lines, never closer to a flanking street than the house. 4.0 m from the house (7.5 m behind it in rural zones); in a side yard, 5.0 m back from the front wall. |
| Access path | A clear path at least 1.0 m wide and 2.1 m high from the street to the detached unit's door. The City's checklist caps it at 45 m long, and laneways do not count. |
| Existing garage or shed | A legal accessory building that existed on May 12, 2021 may be converted. Adding more than 10% to it brings in the full detached ADU rules. |
| Parking | No extra spaces needed for up to 3 units, per the City's ADU page. Newer buildings get an added review against the date the by-law passed. |
Last verified 2026-10-11
These are Zoning By-law 05-200, Section 4.33, as consolidated in September 2026. Some lots are still zoned under a former municipality’s by-law, and a site-specific exception can change the numbers. The City’s interactive zoning map shows which applies. A design that does not fit can go to the Committee of Adjustment for a minor variance.
Flat ADU fees, and most DCs waived.
Fees are set by Building By-law 15-058, Schedule A, and paid online when you apply. An application is not accepted until the fee is paid. Planning numbers, not quotes.
| Item | City of Hamilton |
|---|---|
| ADU in an existing house | $515 flat fee |
| Detached ADU in the rear yard | $1,030 flat fee |
| New house or addition | $18.32 per m² of floor area |
| Finishing a basement, alterations with no system changes | $4.06 per m² |
| Deck, porch, exterior stairs | $5.36 per m² |
| Garage, shed, new basement | $6.58 per m² |
| Minimum permit fee | $291 |
| Septic system | $1,010 for a new system, $619 for a Class 5 system or a repair |
| Resubmissions | $187 per hour once a non-compliant resubmission goes past the first one. A clean first package matters. |
| Development charges | 100% exemption from City DCs for up to two ADUs on a detached house, semi or rowhouse (2026 to 2027 pamphlet). A new house itself pays City DCs from $44,415 (rural) to $102,451 (urban), plus $3,579 in education DCs. |
| Education DCs and parkland on an ADU | Set case by case: the City says an ADU may be subject to parkland and development charges, and the plan reviewer and finance team set any amount during permit review. |
Last verified 2026-10-11
The fee page was last updated in March 2025; confirm the current schedule with the City before you budget. Municipal addressing, a lot grading security deposit and a water service upgrade are separate. See how our pricing works.
- ClosedADU and Multi-Plex Housing Incentive Program
A grant of 70% of eligible costs, up to $40,000 per unit. It reached its funding limit and the portal is closed: no new applications, extensions or waitlist.
- OpenCity development charge exemption for ADUs
Up to two ADUs on a detached house, semi or rowhouse, under the current DC by-law.
Everything goes in online.
Zoning and applicable law
Check the zoning map, conservation authority, NEC, heritage and, near the LRT, Metrolinx. Those approvals come first.
Drawings and forms
Floor plans, elevations, sections, site plan, Schedule 1 designer forms, the SB-12 energy form, water pipe sizing, and the calculations the City asks for.
Submit on the portal
A my.hamilton.ca account, then the Customer Portal. The owner or an agent can apply.
Review
Zoning, Building Code, mechanical and fire review. Staff contact you or your agent with a list if anything is missing.
Permit issued
Then the inspections the permit lists, through to occupancy.
- Submission standards. Vector PDFs, not scans; unsecured; black and white; to scale; no markups or layers. A house with up to two units can go in as one combined PDF. Resubmissions carry a version number.
- Grading plan. Detached ADUs, additions and accessory buildings often need a professional grading plan and a security deposit. A detached ADU of 55 m² or less, 1.0 m from the lot lines, or a converted existing building, is usually exempt if drainage features and lot-line grades stay as they are. We tell you early if you need one; we do not prepare grading plans.
- Good Neighbour notice. Detached ADUs and large additions need the residential infill information notice.
- Tarion. A new detached ADU is new home construction for warranty purposes; an owner-builder fills in the builder section.
- Review time. The Building Code gives the City 10 business days to decide on a complete house permit application. Missing pieces restart the clock. Confirm the current target with the City. We do not publish a time for our own work.
Structural work, where a project needs it, is coordinated with an outside licensed professional. Full breakdown: renovation process.
The escarpment runs through the middle.
| Overlay | What it means |
|---|---|
| Hamilton Conservation Authority | Most of the city: ravines, valleys, steep slopes and sections of the escarpment, wetlands, creeks and floodplains, the Dundas Valley, and the harbour and Lake Ontario shoreline, plus land next to them. 905-525-2181. |
| Other authorities | Conservation Halton (905-336-1158) around Waterdown and parts of Flamborough, Grand River (519-621-2761) in parts of the west, and Niagara Peninsula (905-788-3135) in parts of Stoney Creek, Binbrook and Glanbrook. The watershed decides, not the community name. |
| Niagara Escarpment Commission | Lots in the NEC's area of development control need an NEC development permit before the building permit. 905-877-5191. |
| Heritage | A designated property, or one inside a heritage conservation district, needs a heritage permit. Hamilton has eight districts: Cross-Melville, Durand-Markland, Hamilton Beach, MacNab-Charles, Melville-Park West, Mill Street, St. Clair Avenue and St. Clair Boulevard. |
| Zoning compliance review | New single detached houses (and new detached units) in the ER zone of the former Ancaster by-law and along the Hamilton Beach strip need one before the permit. |
| Natural features | The City's Natural Heritage planners (905-546-2424 ext. 1355) can say what features are on or near a lot. |
Last verified 2026-10
What we design in Hamilton.
Basement apartments and garden suites
Permit drawings for a legal ADU, inside the house or detached.
Additions
Rear, side and second-storey additions.
Alteration drawings
Permit drawings for renovations to an existing home.
Load-bearing wall removal
Drawings, with the structural design coordinated.
New builds
Detached and semi-detached homes within House scope.
Do I need a permit?
A self-check before you call anyone.
Hamilton questions.
What does Hamilton charge for an ADU building permit?
The City's fee schedule lists a flat $515 for an additional dwelling unit in an existing house and a flat $1,030 for a detached unit in the rear yard. Grading security, a water service upgrade, municipal addressing or a conservation authority permit can add to that.
How our pricing worksHow many units can I have on one Hamilton lot?
On urban land, Zoning By-law 05-200 allows no more than four dwelling units on a lot with an ADU: for example a single detached house with two ADUs inside and one detached ADU. In the rural zones it is one ADU on a lot over 0.6 ha, plus one detached ADU on a single detached lot of at least 1.5 ha. Some lots still fall under a former municipality's by-law, so check the zoning map for your address.
Does my property qualify?Do I pay development charges on an ADU in Hamilton?
The City's 2026 to 2027 pamphlet lists a 100% exemption from City development charges for up to two additional dwelling units on an existing or new detached house, semi or rowhouse. Education charges and parkland are handled separately, and the City's own ADU page says the plan reviewer and financial team decide what applies to your file.
Is the ADU grant still open?
The Additional Dwelling Unit and Multi-Plex Housing Incentive Program reached its funding limit and the City closed the application portal. It is not taking new applications, extensions or a waitlist.
Other ways to pay for itCan a detached ADU have its own water and sewer connection?
Not in Hamilton. The City only permits servicing connected through the main house. The building permit also needs a water pipe sizing form, and the City may require a larger water service before it issues the permit.
Do I need to add parking for an ADU?
The City's ADU page says the amended by-laws exempt additional parking spaces for up to 3 units. Newer buildings get an extra check against the date the by-law passed, and a fourth unit should be confirmed with zoning staff.
My lot is near the escarpment. What changes?
If the lot is in a conservation authority regulated area, that authority's written permission comes before the building permit, and adding a dwelling unit is one of the things it regulates. Lots inside the Niagara Escarpment Commission's control area also need an NEC development permit. We check both maps before any drawing starts.
Just over the line?
We’ll tell you what the City allows on your lot.
Zoning, units, servicing, the conservation authority and the permit path for your Hamilton address, before you spend anything on drawings.