One Principal Residence per Family Unit: What Couples With Two Properties Need to Know

Our guide to the principal residence exemption covers the general rule and an example of a house and cottage bought by the same couple. This article starts from a situation that is just as common and trickier: two people who each owned a property before moving in together. While single, each could shelter their own home. Once they form a family unit, there is only one principal residence to designate per year for the couple, and the shared years become a trade-off.

The rule: one property per family unit, per year

The definition of "principal residence" in section 54 of the Income Tax Act provides that, for years after 1981, a property can be designated for a year only if no other property has been designated for that same year by the taxpayer or by a member of their family unit. The Canada Revenue Agency's folio on principal residences (S1-F3-C2) sets out the same rule at paragraph 2.13.

Revenu Québec applies the same logic: you can designate only one principal residence for a given year.

For this rule, the family unit includes:

• the taxpayer;
• a person who was their spouse or common-law partner throughout the year, unless living apart from them all year under a judicial separation or written separation agreement;
• their children, except a child who at any time in the year was married, in a common-law partnership or 18 or older.

For the CRA, a common-law partner is, among other cases, someone you have lived with in a conjugal relationship for at least 12 continuous months, or the parent of your child.

Before and after moving in: two regimes for the same properties

The words "throughout the year" have a direct consequence. For years when the two people were not yet spouses or partners, they were not one family unit: each could generally designate their own property, provided they ordinarily inhabited it and met the other conditions.

From the first year they are partners throughout the year, the limit applies to the couple. If each keeps their property, say one partner's city condo and the other's cottage, only one of the two can be designated for each shared year.

The year the relationship starts deserves a close look: depending on when the common-law conditions are met, it may or may not count as a shared year. It is a good point to confirm with a tax professional.

The formula: why the "1 +" helps but does not solve everything

Under paragraph 2.20 of the folio, the exempt portion of the gain works out as:

• capital gain × (1 + number of years designated) ÷ number of years owned.
• Designated years are the years from acquisition for which the property is designated and during which the owner was resident in Canada.
• The remaining taxable gain cannot go below zero: the exemption never exceeds the gain.

The folio explains that the "1 +" exists because the law recognizes you can have two residences in the same year, typically the year you move. For a couple who keep two properties for several years, it covers only one of those years. The other shared years have to be split between the two properties.

Worked example: her condo, his cottage

The figures below are hypothetical and only illustrate the calculation. Camille buys a condo in 2012 for $300,000 and lives in it. Karim buys a cottage in 2016 for $200,000 and stays there regularly; it is his only property. From 2021, they are common-law partners throughout each year, living at the condo during the week and the cottage on weekends. In 2026 they sell both to buy together: the condo for $420,000 (a $120,000 gain) and the cottage for $380,000 (a $180,000 gain).

• Condo: 15 years owned (2012 to 2026). Years before the relationship: 2012 to 2020, 9 years Camille can designate on her own.
• Cottage: 11 years owned (2016 to 2026). Years before the relationship: 2016 to 2020, 5 years Karim can designate on his own.
• Shared years to split: 2021 to 2026, 6 years, with only one designation per year for the couple.

Scenario 1: shared years go mostly to the condo. The condo is designated for 2012 to 2025 (14 years): $120,000 × (1 + 14) ÷ 15 = $120,000, fully exempt. The cottage keeps only 2016 to 2020 and 2026 (6 years): $180,000 × (1 + 6) ÷ 11 = $114,545.45 exempt, leaving a taxable gain of $65,454.55.

Scenario 2: shared years go mostly to the cottage. The cottage is designated for 2016 to 2025 (10 years): $180,000 × (1 + 10) ÷ 11 = $180,000, fully exempt. The condo keeps 2012 to 2020 and 2026 (10 years): $120,000 × (1 + 10) ÷ 15 = $88,000 exempt, leaving a taxable gain of $32,000.

The second scenario leaves a taxable gain that is $33,454.55 lower. The reason: the cottage gained more value per year of ownership (about $16,364 a year versus $8,000 for the condo). That is the usual instinct, not an automatic rule: purchase dates, a later sale of one property or rental use can change the answer.

What the couple needs to coordinate

• Each owner designates, but for one family unit. Each files their own designation for the property they sell, yet any shared year one of them uses is no longer available to the other.
• The choice is final for the property sold. Years designated on one sale are gone for the other property. If one home is kept for several more years, the trade-off has to account for that future sale.
• The form is not optional. Federally, the designation is made on Form T2091(IND) with Schedule 3; in Quebec, on Form TP-274. Revenu Québec states a penalty of $100 per month, up to $5,000, for failing to file it.
• The property must be ordinarily inhabited. A cottage rented out year-round or a condo left empty after the move are not in the same position: the occupancy condition has to hold for each designated year.

These calculations are general information. When two properties, a new relationship and years to allocate overlap, a few hours with a tax professional before filing the return for the year of sale are usually money well spent.