What is it?
A city can prohibit a use when it passes or changes a zoning by-law. But land or a building that was already lawfully used for that purpose on the day the by-law was passed cannot be stopped by the new by-law, as long as it keeps being used for that purpose (section 34 (9) (a) of the Planning Act). This is called a legal non-conforming use.
Examples might be an old corner store inside a residential zone, or an old small workshop in a zone that no longer allows it.
A building that got a building permit before the by-law was passed can still be built and used, as long as the permit was not revoked and the building is used for the purpose it was built for (section 34 (9) (b)).
Three conditions for protection
- It was lawful: the use had to be lawful on the day the by-law was passed. A use that broke the rules from the start is not protected.
- Same purpose: the protection covers only the purpose it was used for on that day. If you switch to another use, the protection does not simply move with it.
- It continues: the Act says "so long as it continues to be used for that purpose". The Act says nothing about breaks in the use, so any stop in the use, even a short one, can put the protection at risk.
If you want to enlarge or change it
- Enlarging the building: the Committee of Adjustment may allow the building to be enlarged or extended if the use continued until the date of the application. It cannot be enlarged beyond the limits of the land owned and used with it on the day the by-law was passed (section 45 (2) (a) (i)).
- Changing to a similar use: the Committee may allow a use that is similar to the original one, or more compatible with the uses the by-law permits. Again, the use must have continued until the date of the application (section 45 (2) (a) (ii)).
- Council amending the by-law: council can amend the by-law to allow land or a building to be extended or enlarged if it continues to be used in the same manner and for the same purpose (section 34 (10)).
The Committee’s permission is not guaranteed. It decides after a public hearing. Only the applicant, the Minister, certain listed bodies (such as utilities) or public bodies with an interest can appeal, within 20 days of the decision (section 45 (12)). The appeal goes to the Ontario Land Tribunal, or to a local appeal body if your city has one (section 8.1 (6), (7)). See "Minor variance" for the process.
Compared with other cases
| Situation | Protected? | Why |
|---|---|---|
| Used lawfully before the by-law, and still used the same way | Yes | Section 34 (9) (a) |
| Built under a building permit issued before the by-law, used for that purpose | Yes | Section 34 (9) (b) |
| A use started after the by-law was passed | No — a rezoning or minor variance may be needed | The use did not exist on the day the by-law was passed |
| A use allowed by a temporary use by-law whose time has run out | No | Section 39 (4) |
| A use that stopped and then started again | The protection may have been lost | The "it continues" condition |
What to check when buying
- Proof: ask the seller for proof that the use has continued lawfully from the day the by-law was passed until now (for example, old building permits, city records, rental records), and review it with your lawyer.
- Vacant periods: if the property sat empty for a long time or the use ever stopped, ask your lawyer and the city whether the protection still applies.
- Your plans: if you plan to enlarge it or switch to another business, you may need the Committee of Adjustment’s permission, and the outcome is not guaranteed.
- The protection follows the use: you are safest carrying on exactly the same use. If you use it for a different purpose, you may fall outside the protection.
Example
(A made-up example) You want to buy a building in a residential zone with an old corner store on the ground floor. Today’s zoning does not allow a store there, but the seller says the store has run since before the by-law was passed.
With your lawyer you check old records to confirm the store never stopped. You plan to keep the same kind of store. Before you write the offer, you also learn that enlarging it would need permission from the Committee of Adjustment or a by-law change by council.
What the law and official sources say
Quotes are copied word for word. The "In plain words" lines are our explanation, not an official translation.
No by-law passed under this section applies, (a) to prevent the use of any land, building or structure for any purpose prohibited by the by-law if such land, building or structure was lawfully used for such purpose on the day of the passing of the by-law, so long as it continues to be used for that purpose;In plain wordsA use that was lawful on the day the by-law was passed cannot be stopped by that by-law, as long as the use continues.
Source: ontario.ca/laws/statute/90p13 · checked Oct 30, 2026
(b) to prevent the erection or use for a purpose prohibited by the by-law of any building or structure for which a permit has been issued under subsection 8 (1) of the Building Code Act, 1992, prior to the day of the passing of the by-law, so long as the building or structure when erected is used and continues to be used for the purpose for which it was erected and provided the permit has not been revokedIn plain wordsA building with a permit issued before the by-law was passed can still be built and used, as long as the permit was not revoked under the Building Code Act and the building keeps being used for the purpose it was built for.
Source: ontario.ca/laws/statute/90p13 · checked Oct 30, 2026
Despite any other provision of this section, any by-law passed under this section or a predecessor of this section may be amended so as to permit the extension or enlargement of any land, building or structure used for any purpose prohibited by the by-law if such land, building or structure continues to be used in the same manner and for the same purpose as it was used on the day such by-law was passed.In plain wordsEven for a use the by-law prohibits, council may amend the by-law to allow the land or building to be extended or enlarged if it is still used in the same manner and for the same purpose as on the day the by-law was passed.
Source: ontario.ca/laws/statute/90p13 · checked Oct 30, 2026
(a) where any land, building or structure, on the day the by-law was passed, was lawfully used for a purpose prohibited by the by-law, may permit, (i) the enlargement or extension of the building or structure, if the use that was made of the building or structure on the day the by-law was passed, or a use permitted under subclause (ii) continued until the date of the application to the committee, but no permission may be given to enlarge or extend the building or structure beyond the limits of the land owned and used in connection therewith on the day the by-law was passedIn plain wordsIf the lawful use from the day the by-law was passed continued until the application, the Committee may allow the building to be enlarged, but not beyond the land owned and used with it on that day.
Source: ontario.ca/laws/statute/90p13 · checked Oct 30, 2026
(ii) the use of such land, building or structure for a purpose that, in the opinion of the committee, is similar to the purpose for which it was used on the day the by-law was passed or is more compatible with the uses permitted by the by-law than the purpose for which it was used on the day the by-law was passed, if the use for a purpose prohibited by the by-law or another use for a purpose previously permitted by the committee continued until the date of the application to the committee;In plain wordsThe Committee may allow a change to a use that is similar to the original one, or more compatible with the permitted uses, if the original use (or one the Committee allowed before) continued until the application.
Source: ontario.ca/laws/statute/90p13 · checked Oct 30, 2026
Common questions
How many months empty before the protection is lost?
The Planning Act gives no number of days or months. It only says "so long as it continues to be used". If the property sat empty for a while, the answer can depend on the facts, so check with your lawyer.
Does a new owner get the same protection?
The Act talks about the use of the land or building. It says nothing about a change of owner. So the protection may continue after a sale if the same use carries on without a break, but this is only a reading of the wording, so confirm it with your lawyer. Make sure the use does not stop around closing.
Can I renovate or enlarge a non-conforming building?
To enlarge it, you may need permission from the Committee of Adjustment (section 45 (2) (a) (i)) or a by-law amendment by council (section 34 (10), if it is still used in the same manner and for the same purpose). To switch to a similar use, you may need permission from the Committee (section 45 (2) (a) (ii)). Before any construction, ask the city’s building department whether you need a building permit.
Guides that use this term
Sources checked
- Planning Act, R.S.O. 1990, c. P.13, ss. 8.1, 34, 39, 45 (e-Laws) · checked Oct 30, 2026