Mississauga has some of the highest demand in the GTA for basement apartments, garden suites, and fourplex conversions, and one of the most structured digital permit systems. This guide walks through how to get a building permit in Mississauga in 2026, including the ePLANS portal, second-unit registration, fees, and timelines.
The ePLANS Portal
Mississauga accepts building permit applications digitally through its ePLANS portal. The City enforces strict file standards - drawings must be uploaded as individual, unsecured, greyscale PDFs in landscape orientation - and applications go through a pre-screen before the fee is paid and review begins. Drawings prepared to these exact standards clear the pre-screen instead of bouncing back.
Second Units & Registration
A legal basement apartment in Mississauga requires two things: a building permit and second-unit registration. After the work passes final inspection, you submit proof of ownership and the signed-off permit to the City to receive a Registration Certificate. An unregistered unit is not legal even if it was built with a permit.
Garden Suites & Fourplexes
Mississauga permits garden suites with specific setbacks (for example, 1.8 m at the rear and 0.6 m at interior side lot lines) and lot-coverage limits, and has moved to allow fourplexes on many low-rise residential lots. These multiplex conversions must resolve fire separation, independent egress, and separate services for each unit.
Mississauga Permit Fees
Mississauga calculates its permit fee per square metre of construction value, with a residential minimum around $244 and typical fees from $400 to $3,000+. This is separate from your BCIN designer fee. See our 2026 cost guide.
Process & Timeline
After a zoning check, we prepare the ePLANS-formatted drawing set (usually 5-10 business days), submit with Schedule 1, and respond to examiner comments. Ontario targets a 10-business-day review for houses once the application is complete. See our permit process guide.
Planning a project in Mississauga?
Call 416-558-9607 or request a free quote. We prepare ePLANS-ready, BCIN-certified drawings.