ImmoMulti — a direct buyer of income properties on Québec's North Shore — regularly sees plex buildings whose use no longer complies with the current zoning by-law: a triplex in a zone now limited to duplexes, one unit more than the grid allows, a commercial use on the ground floor of a multi-unit building. The good news: such a use may be protected by acquired rights. The bad news: those rights are not eternal. They can be lost through abandonment of the use, destruction of the building, or a change of use. Understanding these rules before you sell your plex can be the difference between a smooth transaction and a sale that collapses at financing.
What is an acquired right in zoning terms?
An acquired right with respect to a lot, construction, use or sign allows the owner to maintain and enjoy a situation of fact even if it no longer complies with the new planning regulation, according to the Government of Québec. It is based on the principle of non-retroactivity of regulations.
The principle is simple to state. When a municipality adopts or amends its zoning by-law, the new rules generally cannot apply retroactively to situations that already existed legally. This is what the Government of Québec calls the principle of non-retroactivity: laws and regulations cannot affect situations that existed before they came into force, unless otherwise provided.
Concretely, if your plex had three units and that use complied when it was built, a later by-law limiting the zone to duplexes does not make your triplex illegal overnight. It becomes nonconforming — meaning it no longer matches the current by-law — but protected by acquired right. You can continue to enjoy it, maintain it, and carry out necessary repairs.
This is a fundamental distinction for a multi-unit owner: "nonconforming" does not mean "illegal." A protected nonconforming use is entirely legitimate. The risk lies not in its existence, but in the events that can bring it to an end.
Source: Government of Québec — Land use planning decision guide, "Planning by-laws and acquired rights".
How a protected nonconforming use actually works
As long as a nonconforming use protected by acquired right continues to be exercised, the acquired right remains. An owner or a new buyer can rely on it on condition of maintaining the same activity. The municipality may adopt specific rules to govern these uses.
According to the Government of Québec, the existence of an acquired right on a building or nonconforming use allows its owner to continue enjoying the property and authorizes maintenance and necessary repairs. A crucial point for a seller: as long as the nonconforming use continues to be exercised, the acquired right remains, and a new owner or tenant can rely on it, on condition of maintaining the same activity.
This is what makes such a plex sellable: the acquired right transfers with the building, as long as the use is neither interrupted nor changed. A buyer who takes over a nonconforming but protected triplex continues to benefit from the protection, exactly as the seller did.
The Government also notes that a municipality may find it useful to regulate lots, constructions, uses and signs protected by acquired rights by adopting specific rules. The advantage: clarifying the applicable rules and making it easier to settle disputes when an acquired right is claimed at the time of a permit application. In other words, two neighbouring municipalities may govern the same acquired rights differently — hence the importance of checking your own municipality's by-law.
A protected nonconforming use, in practice, is:
- A use that existed legally before the current by-law came into force;
- A use you can maintain and keep up (necessary repairs);
- A right that transfers to the buyer as long as the activity is not interrupted;
- A right governed by your municipality's by-law, which may set its limits.
How are acquired rights lost? The three traps
An acquired right on a use is lost mainly in three ways: cessation or abandonment of the use for a period set by the municipality (never less than six months under section 113 of the Act respecting land use planning and development), destruction of the building where it has lost at least half its value, and replacement of the nonconforming use with a different nonconforming use.
This is where everything is at stake for a seller. An acquired right is robust as long as you respect it, but fragile in the face of three specific events.
1. Cessation or abandonment of the use
According to the Government of Québec, the municipality may require a nonconforming use to cease if it has been abandoned, discontinued or interrupted for a period it defines — a period which can in no case be less than six months. This power flows from section 113 of the Act respecting land use planning and development. A nonconforming plex left vacant, or whose "extra" unit stops being rented for several months, risks having its use challenged. For an owner preparing a sale, letting occupancy lapse is therefore a direct risk to value.
2. Destruction or loss of the building's value
Still according to the Government of Québec, where a construction is destroyed, becomes dangerous, or has lost at least half its value, rebuilding rules apply. The common reference threshold is 50% of value. Depending on the municipality's by-law, the owner may then be unable to rebuild to the same nonconforming use. This is the dreaded scenario after a major fire: the protected triplex may, in the worst case, only be able to return as a compliant duplex.
3. Change of the nonconforming use
You cannot replace a nonconforming use with a different nonconforming use: lost acquired rights are not transferred to a new use. Likewise, enlarging or intensifying the nonconforming use (adding a unit, extending the occupied area) is generally not covered by mere protection and may cause the acquired right to be lost.
Warning: an illegal permit protects nothing
According to the Government of Québec, a permit or certificate issued illegally does not create any acquired right. If an additional unit was added to your plex without a valid permit, or a basement unit was built without authorization, the use is not necessarily protected — even if it has existed for years. Have the validity of the original permits checked before listing.
Sources: Government of Québec — "Planning by-laws and acquired rights"; Act respecting land use planning and development (A-19.1), s. 113.
What it means for the value and sale of your plex
A clearly protected and documented nonconforming use does not necessarily lower a plex's value. It is uncertainty about the acquired rights — for the buyer and their lender — that creates a discount, conditions, or a withdrawn offer.
For a buyer, a nonconforming multi-unit building raises three questions: is the use really protected? Will the lender finance a building that does not comply with zoning? And what happens after a loss? Each of these uncertainties is paid for in dollars. Here is how the two situations differ.
| Situation | Documented acquired right | Uncertain acquired right |
|---|---|---|
| Bank financing | Generally possible, the use being legitimate | Lender reluctance, conditions, or refusal |
| Risk after a fire | Known and quantifiable by the buyer | Perceived as an open risk (50% threshold) |
| Price offered | At market for a plex of its category | Discount, holdbacks, or withdrawn offer |
| Time to sell | Normal | Lengthened by due diligence |
The message for the seller is clear: the protection exists, but it must be proven. A plex whose acquired rights are clearly established sells at the price of its category. A plex where no one can confirm whether the third unit is protected sells for less — or not at all.
"An acquired right with respect to a lot, construction, use or sign allows the owner to maintain a situation of fact and enjoy it, even if that situation no longer complies with the new planning regulation."
— Government of Québec, Land use planning decision guideHow to prove and document your acquired rights before selling
Proof of acquired rights generally relies on documents showing the use existed and was compliant before the current by-law came into force. Gather as early as possible:
- The original construction or renovation permit showing the authorized number of units;
- The historical assessment roll and tax bills showing the number of units over time;
- Old leases, rent receipts, and rent registers showing continuous occupancy;
- Dated photos and, where possible, an up-to-date certificate of location;
- Any specific rules adopted by your municipality to govern protected uses.
Since the burden of proof usually falls on the party claiming the acquired right, this file is no small detail: it is what reassures the buyer, the lender, and the notary. An up-to-date document package prepared before listing completes the picture. For complex situations — an added unit, mixed use, a basement unit — consult a notary or a municipal-law lawyer, who can confirm the status with the municipality.
Selling a nonconforming-use plex on the North Shore
On the North Shore — Terrebonne, Mascouche, Blainville, Boisbriand, Saint-Jérôme, Saint-Eustache, Deux-Montagnes — many older plexes were built at a time when zoning was different. Many of these multi-unit buildings today enjoy perfectly valid acquired rights. The problem is almost never the right's existence: it is the lack of documentation that scares off traditional buyers and lengthens timelines.
A specialized buyer understands how acquired rights work and knows how to value a nonconforming use fairly, without panicking at the sight of a protected triplex in a duplex zone. This is exactly what a direct sale offers: no buyer frightened by the word "nonconforming," no financing that stalls at the last moment. If you are preparing a sale and the acquired-rights question worries you, first compare your options with our guide on the timing of a plex sale, and read our North Shore market analysis.
ImmoMulti buys income properties on the North Shore — including those whose use is nonconforming but protected — with no broker and no commission, and a confidential offer within 48 hours. You do not have to untangle the regulatory puzzle alone before you sell.
Informational content only. Acquired-rights and zoning rules vary by municipality and by-law, and provisions are subject to change by the Government of Québec and the local municipality. Consult a notary, a municipal-law lawyer, or your municipal building department for advice specific to your property.