The Bylaws

Hamilton’s newest ADU bylaws (22-132 – 22-138 which replaces 21-071 – 21-079) are available on the City’s website. One change that was made is that the acronym was changed from SDU (secondary dwelling units) to ADU (additional dwelling units) since you are able to have 2 on a site (one inside the main house, one detached in the back yard). These new zoning bylaws replace the pilot Laneway House zoning 18-299. While the Laneway House pilot zoning was only for part of Wards 1-4 on lots that abut a laneway, the SDU zoning is for ALL Low Density lots in Hamilton within the urban boundary. We have downloaded the various bylaws below for reference. Since just after Hamilton was amalgamated in 2000, staff have been working on a new Official Plan and bylaws to merge all the zoning bylaws. While that process is still ongoing, there are separate versions of the SDU bylaw for each former municipality.

ADU Planning Staff Reports

The following reports and presentations were developed by City staff during the development of the ADU bylaws.

PED 20093 – Secondary Dwelling Units – Options to Increase Housing Supply in Hamilton’s Existing Low Density Housing Stock (City Wide)

PED 20093a (follow up)

Staff Presentation 2021.04.06

Residential Zoning Bylaw website, City of Hamilton 2021.05.14

What are the Limitations?

In general, you can build a detached ADU on any lot within the urban boundary of Hamilton as long as it fulfills the following requirements (note: there are many other requirements in the bylaws, please refer to them for your specific site context).

  • One Additional Dwelling Unit – Detached shall be permitted on a lot containing a Single Detached Dwelling, a Semi-Detached Dwelling or a Street Townhouse Dwelling (one ADU is also allowed within the Primary Dwelling, such as a basement apartment).
  • ADU gross floor area no more than 75m2
  • Max lot coverage of ADU 25%
  • Gross floor area of ADU cannot be larger than the primary dwelling
  • 7.5m setback between ADU and primary dwelling
  • 1.2m setbacks on side and rear lot of ADU
  • ADUs can have no more than two bedrooms
  • Max building height 6m
  • No rooftop patios or balconies
  • No additional parking required for the ADU
  • Existing water service size to property. Note that the City of Hamilton will now not issue a building permit for an ADU without the water service to the site first being upgraded (if needed, very common). Fill out the linked form for the existing house + the proposed new SDU to determine if you need to upgrade the water service line first. Sizing of Water Service Pipe Form – More Than One Dwelling Unit

The Bylaws (organized by former municipality)

22-132 Updates to bylaw 05200

22-133, Ancaster

22-134 Dundas

22-135, Flamborough

22-136 Glanbrook

22-137 Hamilton

22-138 Stoney Creek

21-078 Parkland Dedication

21-079 Reduced Minor Variance Fee

Modifications and Updates to Secondary Dwelling Unit and Secondary Dwelling Unit – Detached Regulations

On June 8, 2022, the City of Hamilton Council approved By-law Nos. 22-13222-13322-13422-13522-13622-137 and 22-138 – Updates to the Secondary Dwelling Unit (SDU) and Secondary Dwelling Unit – Detached (SDU-D) regulations of City of Hamilton Zoning By-law No. 05-200 and the Former Community Zoning By-laws of the Town of Ancaster, Town of Dundas, Town of Flamborough, Township of Glanbrook, and City of Hamilton.

The changes to the City’s Secondary Dwelling Unit and Secondary Dwelling Unit- Detached regulations are intended to provide clarity and consistency to the in-effect regulations that will improve by-law interpretation and ease implementation going forward. They include

  • Separate Secondary Dwelling Unit and Secondary Dwelling Unit – Detached regulations into two different sections;
  • Remove redundant regulations;
  • Align Secondary Dwelling Unit and Secondary Dwelling Unit – Detached regulations with the parent Zoning By-laws;
  • Provide clarification to the existing parking regulations for Secondary Dwelling Unit and Secondary Dwelling Unit – Detached in all Zoning By-laws; and,
  • Make technical and cross-referencing updates to provide consistency in all Zoning By-laws.
  • City of Hamilton Zoning By-law No. 05-200: Change the title from Secondary Dwelling Units and Secondary Dwelling Units – Detached to Additional Dwelling Units and Additional Dwelling Units – Detached to align with the changes to Low Density Residential Zones.  
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