Can a garden suite have its own water and sewer?
No. The City's answer to that question: The City of Hamilton only permits servicing connected through the principal dwelling.
And on the Building Code list: Separate servicing for a D-ADU is not permitted.
(City of Hamilton, Additional Dwelling Units, read November 5, 2026) So the water and sewer lines run from the house out to the suite.
Will the water service need upgrading?
Possibly. A second home adds a kitchen, a bathroom and laundry. The City: Depending on the proposal the existing water service may not be adequate to service the total number of plumbing fixtures. A water service upgrade to a larger pipe size and larger water meter may be required.
A lead pipe may need replacing, and the servicing must be approved before the permit is issued. A water pipe sizing form is required (City of Hamilton, Additional Dwelling Units, read November 5, 2026).
What else does the City require?
| Item | Requirement |
|---|---|
| Water and sewer | Through the main house only |
| Fire access | A clear path from the street, at least 1.0 m wide with 2.1 m of headroom, to the suite's door; a City laneway does not count |
| Exit | A door straight outside, on that path |
| Parking | No extra space needed for up to 3 units, with more review for newer buildings |
| Builder | The City says a Tarion builder is required for a new detached ADU |
| Address | Its own municipal address, with its own fee |
Each row is from the City's ADU page (City of Hamilton, Additional Dwelling Units, read November 5, 2026). On the builder row, who may build a new home explains the HCRA licence and Tarion enrolment behind it.
Does the yard need a grading plan?
A detached ADU is on the City's list, unless it is small and far enough from the lot lines: lot grading plans has the exemptions. Whether the suite fits the lot at all is in the garden suite fit checker, and the full comparison with a basement unit in basement unit or garden suite.
How does JDT plan it?
The suite, the path and the service runs are drawn on your lot before there is a price. The ADUs page has how a JDT ADU build runs.