Common Mistakes with Tax and Home Loans

If you hold property in your name without considering how tax applies to the debt, you could be paying thousands more than necessary each year.

For WA Government employees with stable income and long-term tenure, the way you structure a home loan affects not only what you pay now, but how much wealth you retain over the next decade. Holding all debt against an owner-occupied property while leaving investment debt unfunded is a common setup that costs more in tax than it should. So is failing to separate borrowing for different purposes when your situation changes.

Deductibility Depends on How the Borrowed Funds Are Used

Interest on a loan is only tax-deductible if the borrowed funds are used to purchase an income-producing asset. It does not matter what security the loan is held against. If you borrow against your home to buy an investment property, that interest is deductible. If you borrow against an investment property to renovate your home, it is not.

This becomes relevant when WA Government employees refinance or restructure debt. If you pay down investment debt with cash and then redraw to cover personal expenses, you convert deductible debt into non-deductible debt. Once that happens, you cannot reverse it without repaying and reapplying.

Using an Offset Account for Owner-Occupied Debt While Keeping Investment Debt Separate

Consider a WA Government employee who owns a home in Canning Vale and purchases an investment property in Kwinana. The home loan sits at $420,000. The investment property loan is $380,000. Both loans have offset accounts.

If they park $50,000 in savings into the offset linked to the home loan, they reduce the interest charged on non-deductible debt. If they had placed that $50,000 into the offset linked to the investment loan instead, they would reduce deductible interest and increase their tax bill. Over a year, depending on their marginal tax rate, that decision could cost between $600 and $1,200 in additional tax.

The principle is to minimise non-deductible debt and maximise deductible debt. Savings should sit against the loan where interest provides no tax benefit. Investment debt should remain as high as serviceability allows, provided the property generates income and the loan structure remains compliant.

Avoiding Contamination When You Convert a Home Into an Investment Property

When you move out of your home and convert it into a rental, the loan attached to that property does not automatically become deductible. Deductibility is based on what the borrowed funds were used for at the time of drawdown, not the current use of the property.

If you had redrawn from the loan to pay for renovations, a car, or other personal expenses before converting the property, that portion of the loan remains non-deductible even after tenants move in. The same applies if you refinanced and took cash out for non-investment purposes.

To preserve full deductibility, avoid redrawing from a loan on a property you may later rent out. If you need funds for personal use, structure a separate loan or line of credit from the outset. Some WA Government employees also choose to set up a loan health check before making a property decision to confirm their structure will hold up under a change of use.

Splitting Loan Purposes Before They Get Mixed

A fixed rate and variable rate split loan is common, but splitting by purpose is just as useful. If you need to borrow additional funds after your initial purchase, and those funds will be used for different purposes, establish a separate loan account.

For instance, if you own a home in Baldivis with a $400,000 loan and later borrow another $60,000 to buy a small commercial property or fund shares, that $60,000 should sit in a separate split. If it gets added to the existing home loan and you make lump sum payments later, you cannot control which portion of the debt you are reducing. Payments will reduce both portions proportionally, and you lose the ability to target non-deductible debt first.

Some lenders allow you to split an existing loan retrospectively if you can demonstrate the purpose of each portion at the time of drawdown. Others do not. Setting it up correctly from the start avoids the need to reconstruct records later.

What Happens When You Refinance or Consolidate Debt

Refinancing to access equity or reduce your rate is common among WA Government employees, particularly those looking to expand their property portfolio or fund renovations. But refinancing can also destroy your ability to claim interest if the new loan mixes deductible and non-deductible debt.

If you refinance a $300,000 investment loan and a $200,000 owner-occupied loan into a single $500,000 facility, you can no longer identify which portion of the interest relates to which purpose. The Australian Taxation Office will not accept an allocation based on your intention. You must be able to demonstrate the use of funds with loan documents, contracts, and transaction records.

When refinancing, ask your broker or lender to maintain separate loan accounts for each purpose, even if they sit under the same mortgage. This adds no cost and preserves your ability to claim what you are entitled to.

Capitalising Interest and LMI on Investment Loans

When you purchase an investment property, you can choose to capitalise certain costs into the loan rather than paying them upfront. This includes Lenders Mortgage Insurance and interest charged during construction or settlement.

Capitalising these costs means the borrowed amount is higher, but because the funds are still being used for investment purposes, the interest on the full loan amount remains deductible. This can improve cash flow in the early years of ownership, particularly if you are holding a property in a suburb like Rockingham or Mandurah where rental yield may be modest relative to the purchase price.

If you are accessing a low deposit loan with LMI, confirm with your broker whether capitalising the premium is an option. Not all lenders allow it, and some limit how much can be added to the loan amount depending on your LVR.

Claiming Interest on Loans for Renovations to an Investment Property

If you borrow to renovate a property that produces rental income, the interest is deductible as long as the funds are used for that purpose. If you borrow to renovate your own home, it is not.

But if you later convert your home into an investment property after renovating it, the interest on the renovation loan does not become deductible retrospectively. It remains non-deductible because the funds were used on a non-income-producing property at the time.

This distinction matters for WA Government employees who plan to upgrade and rent out their current home rather than sell. If that is your intention, consider whether delaying the renovation until after the conversion would allow you to claim the interest, or whether establishing a separate loan for future investment-related work would provide a clearer structure.

Call one of our team or book an appointment at a time that works for you. We work with WA Government employees to structure loans that align with how you plan to use your property, not just how it sits today.

Frequently Asked Questions