A building permit is required for new finishing or for alterations to a basement within dwellings and/or where there are new plumbing fixtures or existing fixtures are being relocated.
This applies to both finished and unfinished basements.
If you are finishing your basement, you will require a building, and plumbing permit if plumbing work is taking place.
A building permit is required if the proposed work involves additional sleeping accommodations or structural alterations.
A plumbing permit is required for additional plumbing fixtures or alteration to existing plumbing fixtures.
In addition, if your home is serviced by an on-site private sewage disposal system, a septic permit may be required.
If you are finishing your basement to become a separate dwelling, a special permit and registration is required.
It is important to note that not all Municipalities allow Basement Apartments. For example, in Toronto, owners of single family detached houses, semi detached houses, and townhouses can convert their basement to separate apartments as long they comply with the Building code requirements and certain provisions related to Zoning such as number of parking spaces. Furthermore, in Toronto (Toronto and East York, Scarborough, North York, and Etobicoke) a house must be at least 5 years old to be able to license its basement as a separate apartment.
Similar regulations are in place in Mississauga, Brampton, Aurora, Newmarket, Barrie, Pickering, and Ajax.
Whereas some Municipalities do not permit Basement apartments, such as the City of Vaughan, Markham, and Richmond Hill.
It is always advisable to call the Building Department at your Municipality to verify such information.