| Scenario | Classification | Deductible | Explanation |
|---|---|---|---|
| Removal of mould from bathroom wall | Repair | Yes | Restores to original condition |
| Replacement of moisture-damaged plasterboard | Repair | Yes | Necessary to remedy the damage |
| Installation of entirely new ventilation system | Improvement | No | Increases value and substantially extends lifespan |
| Repainting of mould-damaged wall | Repair | Yes | Restores appearance after repair |
| Replacement with higher insulation standard | Improvement | No | Upgrade beyond original standard |
| Cleaning and disinfection | Repair | Yes | Necessary part of mould treatment |
Mould damage on a rental property is a repair cost you can deduct from your taxable rental income, provided the work restores the property to its original condition and does not improve it. The boundary between repair and improvement is crucial for tax deduction purposes.
Deduct mould damage from tax: Repair or improvement?
When you rent out a property, you are obliged to keep it in good condition. Mould damage often arises from moisture, poor ventilation or leaks. The cost of treating mould is classified as an operating expense and can be deducted from your rental income on your tax return.
The distinction between repair and improvement is central. A repair restores the property to its former state. An improvement increases its value or substantially extends its lifespan. Only repairs are deductible as running costs.
Which mould damage costs can you deduct?
You can deduct costs for:
- Removal of mould from walls, ceilings and floors
- Repair of moisture damage that caused the mould
- Replacement of moisture-damaged plasterboard or insulation
- Cleaning and disinfection of surfaces
- Minor repainting to cover mould damage
You cannot deduct:
- Extensive renovation of rooms
- Replacement with better insulation or ventilation than the original
- Upgrading materials to a higher standard
- Installation of entirely new systems
Deduct mould damage from tax: Documentation and accounting
To deduct mould damage, you must document the cost carefully. Keep all invoices, quotations and receipts from contractors. The documentation should show what was repaired, when the work was carried out and the cost.
Under the Bookkeeping Act (bokföringslagen), you must retain accounting records and supporting documents for an extended period. This also applies to mould repairs.
Report the cost on your tax return under property expenses. If you are VAT-registered (F-skatteskyld), the cost is reported in your VAT return. The expense reduces your taxable rental income.
Step-by-step: How to deduct mould damage
- Identify the problem — Document the mould damage with photographs and notes on extent and cause.
- Obtain a quotation — Get at least one quotation from an authorised moisture remediation or building contractor.
- Carry out the repair — Ensure the work is carried out according to the quotation and that it is repair only, not improvement.
- Keep all receipts — Collect invoices, receipts and payment proof.
- Classify correctly — Note that this is an operating expense, not a capital investment.
- Report on your tax return — Enter the cost under property expenses on your self-assessment or through an accountant.
- Archive according to law — Keep all documentation in accordance with the Bookkeeping Act.
Repair or improvement: Practical examples
Mould damage and insurance: What does your insurer cover?
Mould damage on a rental property can often be covered by insurance, but it depends on the type of insurance and what caused the mould. A home insurance policy typically covers acute water damage from leaks, but not mould arising from poor ventilation or slow moisture ingress.
If your insurance covers the mould damage, you receive compensation from the insurance company. This compensation counts as insurance income and must be reported on your tax return. You cannot deduct the repair cost from tax at the same time as receiving insurance compensation — this would constitute double compensation.
If your insurance does not cover the mould damage, the repair cost is an operating expense that you can deduct from your rental income. Contact your insurance company to clarify what is covered. Many insurers require you to document the damage immediately with photographs and report it within a certain time. Keep all correspondence with your insurer together with repair invoices for your accounting records.
Frequently asked questions
Can I deduct mould damage if the tenant caused it? Yes, you can deduct the repair cost regardless of cause. You can then attempt to recover the cost from the tenant through the deposit or legal action, but for tax purposes the cost is deductible for you.
How long must I keep the documentation? You must keep all accounting records and supporting documents in accordance with the Bookkeeping Act. This also applies to mould repairs.
Can I deduct mould damage if the property is insured? If your insurance covers the mould damage, you receive compensation from the insurance company. You cannot deduct the cost twice — neither from tax and from insurance at the same time. Report the compensation as income.
What do I do if the mould damage recurs? If the mould recurs, it is often a sign of an underlying problem, such as poor ventilation or moisture ingress. Address the root cause to prevent future damage. Both the original repair and the remedy of the cause may be deductible.
Related articles
Read more about tax planning for rental income:
- What can you deduct when renting out a flat?
- Can you deduct furniture purchases from tax when renting out?
- How to save tax on rental income – with and without VAT registration
- What do you do if the landlord does not repair mould damage?
- Home insurance for rental properties: Everything you need to know (Guide 2026)
This text is general information and does not replace legal advice. Contact an accountant or tax specialist for your specific situation.
