Which builds need one?
The City: Residential infill developments may impact grading and drainage in the immediate and adjacent areas.
So these need a professional grading plan with the permit, unless exempt: residential infill (a single, two family or semi-detached house), a residential addition, a residential accessory building, and a secondary or additional detached dwelling unit (City of Hamilton, Building Permit, read November 5, 2026).
What is exempt?
A build where nothing about the drainage changes at the lot line. The City's exemptions apply only where there is no removal of, or alteration to, any existing development features (e.g. swales, catch basins, area drains, etc.), and no change to grades at the property line(s)
(City of Hamilton, Building Permit, read November 5, 2026):
| Build | Exempt when |
|---|---|
| Addition | 55 m² or less and at least 1.0 m from the lot lines; or over 55 m² and at least 3.0 m away |
| Accessory building or detached ADU | 55 m² or less and at least 1.0 m from the lot lines; or over 55 m² and at least 3.0 m away |
| Any residential project on a big lot | The lot is at least 0.4 hectares (1 acre) and the build is at least 3.0 m from the lot lines |
| Enclosing a porch, deck or carport that already has a roof | Always, under the same no-change condition |
| Converting an existing accessory building into a detached ADU | Always, under the same no-change condition |
| Rebuilding on the existing foundation | Always; with an addition, by the addition rules above |
| A project with its own site alteration permit, site plan grading approval or subdivision agreement | Exempt (a subdivision lot shows a plot plan instead) |
Who may prepare it?
A grading consultant: an Ontario Land Surveyor, a Professional Engineer, a registered Architect or a member of the Ontario Association of Landscape Architects, and an engineer where a private catch basin is proposed (City of Hamilton, Building Permit, read November 5, 2026). The owner retains the consultant, who prepares, seals, signs and dates the plan for the application.
Which JDT builds does it touch?
Most of the outside ones: additions, garages (sheds and detached garages) and garden suites (water, sewer and access for a garden suite). JDT Construction Inc. draws the build on your lot first, which is when its distance from the lot lines, and so the grading question, shows.