Accessory Dwelling Unit


Municipal Office

395 Mulock Drive P.O. Box 328 Station Main, Newmarket, Ontario
L3Y 4X7

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​​In 2013, The Town of Newmarket passed By-law 2013-13 (as amended) which requires all residences with Accessory Dwelling Units (ADUs) to register their units through a one-time application process.

What is an Accessory Dwelling Unit (ADU)?

ADUs are two separate living units within one house. ADUs can be basement apartments, in-law suites, second suites or otherwise. ADUs are required to be registered with the Town of Newmarket's Legislative Services Department.

Each ADU unit must have:

  • a private entrance  
  • a kitchen
  • living quarters
  • sleeping facilities
  • bathroom facilities

If you rent a room in a house or a flat with a shared entrance, kitchen and/ or bathroom facilities, the ADU By- law does not apply to you.

​​Do I need a building permit?

​For questions related to ADUs and building permits, consult the Homeowners Guide to ADUs or contact the Building Department​.

Why do I need to register my ADU? 

Registering your ADU is a matter of health and safety. When you register your ADU, you will receive a small "N" plate (N for Newmarket) to put on the front of your home which identifies that the residence has an ADU.   

The ADU will also be assigned the letter "B" in the primary home address, to show it is a separate residence.

B plate on house for a registered ADU N plate on house for a registered ADU

In case of emergency, the "N" plate and the "B" address will help emergency responders to know there are two units in the home - saving time and potentially saving lives.

 Additionally, houses with an "N" plate are entitled to put out more garbage (from three bags per household to six) and recycling items on their collection weeks, which also improves overall health and safety in the home.

Registration means: responsible landlords and safe tenants.

To register your ADU, please visit this webpage for a step-by-step guide on how to register your ADU. For more information, please visit the ADU Frequently Asked Questions Page.