Selling a Rental Property Without Nine Months of CRA Interest

The situation

Heather, an office manager, and Emily, an IT support lead, had owned a semi-detached house in Brampton for twelve years. They lived in it for the first four, then relocated for work and kept it as a rental for the following eight, collecting rent and claiming the usual expenses on their returns each spring. In early 2026 they accepted an offer to sell, with closing set for a date a few months out. The sale price came in well above what they had paid, and both of them understood, in general terms, that a capital gain — the increase in value between what they paid for a property and what they sold it for — was coming. What neither of them had worked out was how large that gain would be after years of appreciation, or what it would mean for their cash flow in the months after closing rather than the following spring when their return was due.

They came to Treadstone Law before closing, on the recommendation of their real estate lawyer, to get a clear picture of the tax exposure and make sure nothing about the sale itself would create an avoidable problem. A rental property disposition is not usually urgent in the way a closing-week financing shortfall is, but the numbers involved meant getting the timing wrong could be expensive in its own quieter way.

What the review found

The property had sold for roughly $780,000. After accounting for the original purchase price, the cost of a kitchen renovation completed while they lived there, and selling costs, the adjusted cost base — the amount used to calculate the taxable gain — came out to about $570,000. That left a capital gain of roughly $210,000.

Not all of it was taxable. Because Heather and Emily had lived in the property as their home for four of the twelve years they owned it, a portion of the gain qualified for the principal residence exemption, which shelters the increase in value attributable to years a property was an owner's home. Applying that exemption reduced the taxable portion to roughly $140,000. Only half of a capital gain is included in taxable income under the Income Tax Act, so the addition to their combined income for the year was about $70,000 — split between the two of them as joint owners, roughly $35,000 each. Modelling their overall tax position for the year, including their employment income, put the additional combined tax owing on the gain at approximately $31,000.

That figure itself was not the problem. The problem was when it would be paid. Left alone, the natural instinct is to wait: file the return the following spring, see what the CRA (the Canada Revenue Agency) assesses, and pay it then. But income tax in Canada is not a once-a-year obligation for everyone. Once a taxpayer's balance owing crosses a certain point in a given year, the Income Tax Act requires instalment payments — advance payments made during the year the income was earned, rather than settled entirely at filing time. A capital gain of this size, on top of two salaries, was enough to trigger that requirement for the year of the sale. If Heather and Emily simply waited for their April filing to sort it out, the CRA would treat the instalment obligation as unmet and charge arrears interest from the instalment due date that fell shortly after closing — not from the following spring.

Their long-time accountant, Natalia, who had prepared their returns for years, had mentioned in passing that the CRA had been slow lately with assessments and that interest charges arising from processing delays were often waived on request. That is true as far as it goes — the CRA has a discretionary taxpayer relief process that can cancel or waive interest in specific circumstances, including delays caused by the CRA itself. But it is a request, decided case by case, months after the fact, and it is intended for genuine hardship or CRA-caused problems — not as a substitute for paying what is owed on time because the payment was anticipated and simply deferred. Interest continues to accrue, compounding, for the entire period a request sits in the CRA's queue awaiting a decision, and there is no guarantee it will be granted. Building a plan around the hope that relief would clean up nine months of accumulated interest was not a plan; it was a bet, and this dispute existed only on paper so far. The point of pre-sale planning was to make sure it never became a real one.

What we did

1. Modelled the actual gain and exemption before closing. We worked from the purchase documents, the renovation records, and the years of principal residence use to calculate the taxable capital gain with real numbers rather than a rough guess, so the instalment amount that followed was based on the property's actual history.
2. Identified the instalment due date created by the sale. The obligation to pay tax on a large gain does not wait for the following year's filing deadline. We calculated the specific quarter in which a payment was required once the closing pushed their combined income for the year over the instalment threshold, and set that date against their closing timeline.
3. Recommended a voluntary payment at closing rather than a wait-and-see approach. Because the sale proceeds would be in hand at closing, we advised paying the estimated tax on the gain to the CRA around the same time, instead of leaving it to accumulate as an unpaid instalment. Interest on an unpaid instalment starts running from the due date it was missed, not from when the return is eventually filed.
4. Explained why taxpayer relief was not a substitute for planning. We walked through how the CRA's discretionary relief provisions work — what they cover, how long a request typically takes to be decided, and that interest keeps accruing while a request is pending with no assurance of the outcome. Once Heather and Emily understood that a relief application was a fallback for CRA error or hardship, not a planning tool for a known, anticipated gain, the case for paying ahead of time made itself.
5. Coordinated with their accountant on the numbers and the filing. We shared the cost base calculation and the principal residence exemption workings with Natalia so the instalment payment, the eventual return, and the reported gain would all line up without a mismatch flagging for review.
6. Set a clear timeline for the following spring's return. We confirmed which schedules and elections needed to be filed with their return to formally report the disposition and claim the exemption, so the paperwork matched the payment already made.

The outcome

Heather and Emily paid roughly $31,000 to the CRA within days of closing, based on the modelled gain, instead of carrying that amount until the following April. When they filed their return the next spring, the reported gain and exemption matched the estimate closely enough that no further instalment interest applied and no balance came due beyond a small, expected adjustment. No relief application was ever needed, because there was nothing to seek relief from — the interest that would otherwise have accrued for the better part of a year simply never started.

It is worth being specific about what was avoided rather than treating it as an abstract win. Arrears interest on an unpaid instalment compounds daily at a rate the CRA sets and adjusts each quarter, and on a balance of this size, carried from a spring closing until the following spring's filing, the accumulated interest would have run into several thousand dollars — a cost with no offsetting benefit, arising purely from timing. That is the quiet expense pre-sale planning is built to catch: not a dispute to be won, but a bill that never needed to exist in the first place.

What you can learn from this