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Understanding Basement Apartments and Accessory Dwelling Units (ADU's) in Mississauga and the GTA

Update: The Ontario Government has signed into law Bill 140 which allows for basement apartments and Accessory Dwelling Units. All municipalities must provide for these basement apartments.  It's a very involved and complicated process, but it will become law to allow for basement apartments in Mississauga, Toronto and the GTA shortly.  Read more about Accessory Dwelling Units

Accessory Dwelling Units:

City of Mississauga Zoning By-laws do not permit the creation of ADU'S, most commonly known as "basement apartments or conversions."

Some circumstances exist under which an existing accessory dwelling unit may be permitted of it can be established that it was in existence on November 16, 1995. If you have a house that was built after 1995, you are not eligible to create a new ADU or to keep an existing accessory dwelling unit.

Under the previous Provincial legislation, basement apartments created between July 14, 1994 and November 16, 1995 must be exempted from Zoning By-law prosecution as they were deemed to be "grandfathered" if they complied with Fire and Building Code Regulations. ADU's created during this period do not have to comply with current Zoning By-laws, but they do have to meet all other requirements.

The following are some of the minimum requirements that must be met for an ADU to be considered exempted from prosecution and "grandfathered":

ADU's are only permitted in detached, semi-detached or row house dwellings and must have been built prior to 1996.
The appearance or character of the house can not be significantly altered so that its appearance is no longer that of a one unit structure.
The walls and ceilings of all existing stairways must be continuous in the unit and provide a required fire-rated drywall separation between the dwelling units. Doors forming part of the fire separation between units or as an exit must meet specifications relating to thickness and size and be complete with a door closer and latch.

Exits whether shared or separate must meet Fire Code and/or Building Code specifications.
ADU does not have to be secondary to the main unit (smaller square footage).
Compliance with the City of Mississauga Property Standards By-law 654-98, as amended relating to "habitable" space:
Floors, walls, ceilings, exterior walls, water/draft tight and free from dampness.

Windows, skylights for every room other than a kitchen which open directly to the outside and are of a size not less than that required by the Ontario Building Code. Bathrooms maybe equipped with a fan and a heating system capable of providing and maintaining suitable heat in accordance with City of Mississauga Adequate Heat By-law 365-95, as amended.

Minimum ceiling heights (6'5") as required under the Ontario Building Code.

A kitchen equipped with a refrigerator, stove in good repair and working condition.

Cupboards having a capacity of not less than four cubic feet multiplied by the total number of persons occupying the unit.

Counter tops, drawer, plumbing and plumbing fixtures maintained in the good condition and approved by permit in the case of all plumbing.

ADU's must have operational smoke alarms as required, and in conformance with City of Mississauga Smoke Alarm By-law 284-93, as amended or the Ontario Fire Code.
ADU's must have operational carbon monoxide detectors as required by City of Mississauga Carbon Monoxide Detector By-law 77-99, as amended.
Electrical installations must be inspected and certified by the Electrical Safety Authority.
Every second Dwelling Unit which is deemed illegal or exempt from prosecution under the provisions of the Land Use Planning and Protection Act will be reported to Canada Customs and Revenue Agency, Toronto West Taxes Services Office, Investigation Division.
If you have an existing basement apartment and wish to request an inspection to determine its compliance, please contact the Compliance and Licensing Section Call Centre at 905-896-5655.

Any property owner interested in establishing "grandfathering status" and applying for exemption from our Zoning By-law must pay a $250.00 administration and inspection fee.

To help home owners determine if they meet the "grandfathering test" a "requirement check list" has been prepared and should be consulted by all property owners seeking grandfathering status for their ADU.

An affidavit will be requested as a minimum requirement and must be written by the person who can personally attest to the fact that the ADU was in existence on November 16, 1995. This person may be the current owner or former property owner. An affidavit is a written declaration or statement of facts made by the "deponent" under oath or affirmation, and is administered by a person authorized for taking affidavits. (e.g. lawyer)

In addition to an affidavit, property owners will be required to provide such proof as financial documentation (e.g. copies of leases and rent receipts) or real estate listings, as well as an affidavit to provide evidence that the secondary unit did exist on November 16, 1995.

Relevant phone numbers and web sites

Municipal (Property) Standards

Fire Services (Fire Prevention)


Buildings Division

Other Contact Numbers

Shelter, Housing and Support 416-397-4502

Ontario Electrical Safety

Authority (ESA)

(Formerly Ontario Hydro)



For many years the legal status of basement apartments, flats and other accessory residential units which have been added to houses has been unclear. Many municipalities passed zoning by-laws prohibiting these types of apartments in houses. Nevertheless, many thousands of basement apartments and other accessory rental units were constructed. Although the exact number is unknown, it is estimated that as many as 100,000 illegal units were in use across the province in 1993.

In 1994 the N.D.P. government proclaimed Bill 120 the Residents Rights Act. This Bill permitted second units in houses, regardless of Municipal Zoning, provided that Health and Fire safety standards were met. The Ontario Fire Marshal's Office proclaimed Ontario Regulation 385/94 in July of this same year. (retrofit section dealing with Two Unit Residential Occupancies). These two pieces of legislation both mandated the permissibility of, and the safety requirements for Basement Apartments in Ontario.

On November 26, 1995 the new Conservative government introduced Bill 20 restoring back to municipalities the right to outlaw Basement Apartments. This in effect drove these second units back underground. Owners feared prosecution from not only safety authorities, but also local zoning regulations.

Units prior to Nov. 16/95 Grandfathered

However if the unit existed prior to this date (November 16 1995) it was grandfathered, provided it met health and fire standards. The onus is on the owner to prove that this is in fact the case and can be accomplished through the production of rent receipts, presence of tenants on voters list or in some cases the signing of an affidavit for the municipality.

Toronto's Second Suites By-law

On July 6, 2000, the City of Toronto's new "second suites bylaw (493-2000)" came into effect. This bylaw permits second suites in all single-detached and semi-detached houses throughout the City of Toronto, with certain conditions.

Some of the conditions include:

"Caution" Before You Purchase ....

For prospective purchasers of these properties, once the legality of the apartment has been established, then it must be insured that it meets health and fire standards. This can be established by the production of a "Letter of Compliance" from the local Fire Department or the municipality. If this inspection has never been done, or was done a great length of time ago, you may wish to have an Independent Fire Code Inspector report on the conditions to-day. Retrofit legislation calls for the maintenance of the fire safety measures originally built into these two family units. If proper compliance is not indicated at this time you may wish to negotiate with the vendor to perform these upgrades prior to closing, or you may wish to adjust the price accordingly and do the work yourself.

Ontario Fire Code Information

Owners of houses containing two self-contained residential units (dwelling units) are now required to bring their buildings into compliance with the new fire safety regulation adopted under the Ontario Fire Code. Tenants in these buildings are entitled to ask their landlords to make sure that the fire regulations are met.

Some of these Regulations are summarized below.

1.0 What is a Dwelling Unit ?

A dwelling unit is a room or suite of rooms operated as a self-contained housekeeping unit that includes independent cooking, eating, living, sleeping and bathroom facilities.

2.0 Buildings Covered by the New Fire Code Regulation ?

The regulation applies to detached houses, and semi-detached houses, and row houses that contain two existing dwelling units. The two dwelling units may be located anywhere in the house.

3.0 What are the Requirements ?

In general, the regulation contained in the Ontario Fire Code addresses four fire safety issues:

3.1 Fire separation

The owner has three options for compliance with the fire separation for each dwelling unit

3.2 Means of Escape.

Four options are provided for compliance with the means of escape from each dwelling unit.

3.3 Smoke Alarms

Depending on the option selected for fire separation and means of escape, it may be necessary to install electrically wired, interconnected smoke alarms throughout the house. Interconnected smoke alarms are designed to sound simultaneously when any one smoke alarm is activated, providing early warning to all occupants of the house at the same time.

Where interconnected smoke alarms are not installed, every dwelling unit must be equipped with a battery operated or electrically wired smoke alarm on every floor level that contains a bedroom or sleeping area.

All smoke alarms must be maintained in working condition, and they must be audible in the bedrooms when the bedroom door is closed.

3.4 Electrical Safety

The owner must also arrange for the house to be inspected by "the Electrical Safety Authority" and to correct all fire safety hazards identified through this inspection.

4.0 Who is Responsible With Complying With the Regulation ?

The owner is responsible for complying with the provisions of the Ontario Fire Code. Penalties for non-compliance can be up to $25,000 fines and up to one year in prison for individuals.

Owners should be aware that bringing existing houses into compliance with the new regulation may require repairs or alterations for which a building permit is needed under the Building Code Act.

How Do I Bring My House Into Compliance ?

1. The owner can carry out the initial assessment to determine what upgrading
may be required.

2. An Independent Fire Code Consultant can assist you with an assessment and
advise you on the best means of attaining compliance.

3. The Municipal Building and Fire Departments should be contacted, once this
initial assessment is done, to obtain the necessary permits and arrange for
required inspection where appropriate.

Added Income ....

In closing, a basement apartment might be just what you need to provide the added income to make your dream purchase affordable, but beware of the pitfalls and remember that you as a purchaser assume all the liability of a home that doesn't comply, regardless of when you bought it.

Read more about Brampton laws for basement apartments

So, what is your plan with this opportunity and what is your next step in the real estate process?

Mississauga Real Estate Market Professional

Overall average prices.

So, if you are thinking of selling and buying a homes this year, should you buy or sell first?  I've had many clients purchase before they sell.  I just want you to have all the information so you can make the best decision for yourself and your family.  You may read more about buying or selling first here

Read about what happened in real estate last month.

I wish you much success, good health and happiness today and always! 



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