HELOC Strategies That Stay CRA-Clean
A home equity line of credit is secured debt at a floating rate, typically interest-only, capped by loan-to-value rules and by whatever your lender still feels like offering after an appraisal. The tax question is separate from the credit question. Paragraph 20(1)(c) allows interest on money borrowed for the purpose of earning income from a business or property, subject to the limits in the Income Tax Act and in Folio S3-F6-C1. This article is the set of structures that keep that purpose visible. The leveraged loop that readvances your mortgage is the Smith Manoeuvre guide. The decision to borrow at all, versus simply paying the mortgage down, is the prepayment comparison.
The Supreme Court of Canada's decision in Singleton confirmed that you may order your affairs so the borrowed money is the money that is invested, even if you could have invested cash you already had. The direct use of the borrowed funds is what counts. That is permission to be deliberate. It is not permission to be vague. A paper trail is the strategy.
Structures that stay clean
| Structure | The move | What keeps it deductible | What breaks it |
|---|---|---|---|
| Dedicated investment tranche | One HELOC sub-account, or a separate secured line, pays only the non-registered investment account | Every dollar can be traced to income-producing property. Interest for the year is the interest on that tranche. | A single personal draw. Once the balance is mixed, you are allocating by memory. |
| Cash dam on a rental | Gross rent pays down the non-deductible residence mortgage, or sits against personal debt. A separate line pays the rental's operating expenses. | The borrowed money is used to pay expenses of an income-producing property. CRA has accepted cash damming in technical interpretations when the tracing is real. | Paying personal bills from the same line, or "reallocating" an old residence mortgage by intention without a real borrow-and-pay sequence. |
| Debt swap | Sell non-registered investments, pay down the residence mortgage, borrow to repurchase a portfolio | The new borrowing's direct use is the investment. You have converted equity that was trapped in a taxable portfolio into a deductible loan. | A superficial loss if you sell at a loss and you, your spouse, or your registered accounts reacquire identical property inside the 30-day window. A capital gain if you sell at a profit. Both are real tax events. The calendar is the tax-loss harvesting guide. |
| Capitalizing investment interest | Borrow to pay the interest on the investment line itself | Generally sustainable while the underlying investments continue to meet the income purpose. Document the capitalization as its own transfer. | Capitalizing a line that has any personal use, or continuing after you have sold the investments and spent the cash. |
What is not a strategy
- Borrowing to contribute to a TFSA, RRSP, FHSA, or RESP. The income inside is not taxed to you as income from property. The interest is not deductible. Make those contributions with cash. The order is the TFSA and RRSP priority guide.
- Borrowing to renovate a principal residence and claiming the interest because the house "might be sold for more." A hoped-for capital gain on a personal-use home is not the income purpose the folio is describing, and the gain may be sheltered by the principal residence exemption anyway. The exemption's limits are the principal residence versus rental guide.
- A single HELOC that funds investments on Tuesday and a vacation on Friday. Split the facility. If the lender will not split it, track a sub-ledger from day one and do not expect a pleasant audit if the sub-ledger is a spreadsheet you built in April.
- Paying down the line with sale proceeds, then redrawing for personal spending, while telling yourself the old purpose survives. Purpose follows the current use. When the investment is gone, stop claiming.
Payroll, rent, investment draws, and the property-tax bill in one chequing account, funded partly by the HELOC, is not tracing. It is a story. If the borrowed dollars must pass through chequing, move them the same day into the investment or rental account, and do not leave them sitting under a grocery debit. Photograph nothing. Keep the statements.
Cash damming, slowly enough to explain
You already own a rental. Its mortgage interest, property tax, insurance, and repairs are deductible against rental income on the T776, because those expenses were incurred to earn rent. Your residence mortgage interest is not deductible. Cash damming does not invent a new deduction for the residence. It changes which debt finances the rental expenses you were going to pay anyway.
Rent comes in. You use that cash to pay the residence mortgage. You borrow from a dedicated line to pay the rental expenses. Over time, non-deductible debt falls and deductible debt rises, while the rental's economic expenses stay the same. The household is not richer by magic. It is richer only if the tax saving on the newly deductible interest exceeds the cost and the risk of running a second loan. If the line's rate is higher than the residence mortgage, part of the "saving" is an interest-rate swap you should price before you feel clever.
A rental generates $3,000 a month in gross rent. Expenses you would have paid from that rent, excluding the residence mortgage, are $1,400. Under a cash dam you send the $3,000 against the residence mortgage and borrow $1,400 from a dedicated line to pay the rental expenses. In a year you have paid $36,000 extra onto the non-deductible mortgage and borrowed $16,800 to carry the rental. If that $16,800 remains used for the rental, interest on it is the deductible piece. Interest on the residence mortgage is still not. If a month arrives when you also draw $2,000 from the same line for a personal bill, that month's tracing is now a reconstruction project. These dollars are a teaching picture. Your rent and your expenses are not these numbers.
The file you keep before anyone asks
Line 22100 is a claim. Claims have evidence. The audit guide is what a review feels like. For this deduction, the folder is short:
- The HELOC agreement and the annual interest statement, split by tranche if you have more than one.
- Transfer records from the line to the investment account or the rental expense account.
- Brokerage statements showing the investments were purchased with those transfers and were not moved into a registered account.
- A one-page note, written when you started, stating the purpose. Memory is not a contemporaneous note.
- For a debt swap, the trade confirmations, the mortgage paydown receipt, and the repurchase, plus a check against the superficial-loss window if you sold at a loss.
A joint HELOC invested in one spouse's name can raise attribution. The borrower who wants the deduction should be the owner of the investments, and should be the one who is legally liable for the interest being claimed. If you want income in the lower-income spouse's hands, use a structure that is actually designed for that, not an accident of whose login bought the ETF. Get advice before the first transfer. Undoing attribution after the fact is a messier file than the one you meant to create.
A setup sequence
- Decide which of the four structures you are running. One is enough.
- Ask the lender for a separate secured segment with its own statements. Decline the offer to "just use the chequing linked to it" for daily spending.
- Fund investments or rental expenses only. Write the purpose down that week.
- If you are selling investments to swap the debt, check the gain or loss and the 30-day window before you repurchase.
- At tax time, claim interest on the clean tranche only. If you cannot point to the statement, do not estimate.
- If you sell the portfolio or the rental, repay or reinvest before you spend. Then stop claiming what no longer qualifies.
Key takeaways
- Direct use of the borrowed money is the test. Ordering your affairs so the borrowed dollar is the invested dollar is legitimate. Mixing uses is not.
- A dedicated tranche is the whole compliance program for most households.
- Cash damming rotates rental expenses onto a deductible line. It does not make residence interest deductible by wish.
- A debt swap can trigger a capital gain or a denied loss. Price both before you sell.
- Registered contributions and personal renovations do not qualify, however sensible they are as life choices.
- When the investment is gone, the deduction is gone. Repay or reinvest, and keep the statements either way.
Tracing is a habit. The assessment is a tax year.
Carrying charges sit on a return that also has rental income, capital gains, and brackets. The 2026 tax guide is the filing side of the same file.
Get the 2026 Tax Guide — $49 CAD
