There is mould in my property: what to do?
Amina, a tenant in a ground-floor flat in Saint-Gilles, explains how she forced her landlord to deal with a persistent mould problem. Steps taken, registered letters and intervention of the justice of the peace.
October 2024 — the first spots
My name is Amina, I am 26 years old and I have been renting a ground-floor studio in a 1920s building in Saint-Gilles since September 2023. Rent: 700 EUR including charges. The flat is small (32 m2) but well located, 10 minutes on foot from the Midi station. My primary residence lease is a standard 3-6-9.
At the end of October 2024, I noticed black spots in the bathroom grout. I cleaned them with bleach, they disappeared for a week, then came back. In November, similar spots appeared on the bedroom wall, behind the wardrobe. A persistent damp smell settled in. I started coughing at night.
Mould that returns after cleaning points to a structural problem (water infiltration, rising damp, lack of mechanical ventilation). This is not a ventilation issue on the tenant’s part — the landlord is legally obliged to provide a habitable property.
November 2024 — the first report
On 8 November, I sent an email to my landlord, Mr Devos, with 12 photos of the mould. I described my respiratory symptoms and asked for a prompt intervention. He replied by text: “Ventilate better, it’s a condensation problem.”
I followed his advice for 3 weeks: window open 15 minutes morning and evening, despite the November cold. The mould kept spreading. The spot in the bedroom was now 40 cm in diameter. My doctor prescribed a treatment for bronchitis and noted in my medical file that the property was likely the cause.
On 2 December, I sent another email with new photos and the medical certificate. No response.
December 2024 — the formal notice
On 10 December, I sent a registered letter with acknowledgement of receipt. The letter set out:
- The landlord’s obligation to provide a property in good condition (Article 1719 of the Civil Code)
- The regional habitability standards in Brussels (Brussels Housing Code)
- A 30-day deadline to carry out a diagnosis and plan the repair work
- A notice that failing a response, I would refer the matter to the justice of the peace
In Brussels, the Housing Code imposes minimum habitability standards. A property with structural mould can be declared “non-compliant” by the regional inspection, which obliges the landlord to act or face penalties.
Mr Devos acknowledged receipt but still took no concrete action. I decided to move to the next step.
January 2025 — the regional inspection
On 6 January, I contacted the Regional Housing Inspection Directorate (DIRL) of the Brussels-Capital Region. An inspector came on 20 January. The visit was free of charge and did not require the landlord’s consent.
The report was unequivocal: no mechanical ventilation in the bathroom, water infiltration through the rear facade at ground-floor level, humidity level of 78% in the bedroom (maximum standard: 65%). The property was declared “non-compliant with habitability standards.”
The report was sent to Mr Devos with a 6-week deadline to carry out the repairs. This document changed the dynamic: the landlord risked an administrative fine and a ban on renting out the property.
In parallel, I had consulted a free legal aid service (Brussels legal aid office) to prepare a possible procedure before the justice of the peace. Fortunately, the DIRL report was enough.
February 2025 — the repair work
Mr Devos called me on 28 January. A completely different tone. He apologised, acknowledged the problem and proposed a repair plan. A contractor carried out the work between 5 and 12 February:
- Rear facade treatment: hydrophobic injection against rising damp (1,800 EUR)
- Installation of mechanical ventilation in the bathroom (900 EUR)
- Mould treatment and repainting of the affected walls (500 EUR)
Total: 3,200 EUR at the landlord’s expense. I was able to remain in the property during the work.
In the negotiation, I obtained a 2-month rent reduction (1,400 EUR) to compensate for the 4 months of inconvenience and medical expenses. The agreement was formalised through a lease amendment signed by both parties, with a clause providing for a new inspection in 6 months to verify the problem does not return.
What I learned
Six months to obtain repairs that should have been done in a few weeks. Here is what I take away:
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Do not let yourself be guilt-tripped. “Ventilate better” is the landlord’s default response. If the mould returns despite normal ventilation, the problem is structural and it is the landlord’s responsibility.
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The regional inspection is your best lever. Free, fast and official, it transforms the balance of power. In Brussels, it is the DIRL. In Wallonia, contact the Housing service of your municipality. In Flanders, it is Wonen-Vlaanderen.
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Keep paying your rent. Even when it is frustrating. Only the justice of the peace can authorise you to reduce or escrow the rent. Non-payment puts you in the wrong and weakens your position. See our guide on rent to understand your rights.
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Keep a record of everything. Emails, dated photos, medical certificate, copy of the registered letter. My file contained 47 items. That is what allowed me to negotiate the rent reduction without going to court.
If you are in a similar situation, do not stay alone. Front-line legal aid services are free and can guide you. The sooner you act, the sooner the problem will be resolved. For further reading, see our guide on landlord obligations and our other tenant testimonies.
- “**Photograph every spot as soon as it appears, with the date visible.** A chronological photo file is your best asset if the landlord denies the problem or claims it is caused by your lifestyle.
- “**Contact the Regional Housing Inspection Service in your region.** In Brussels, the inspection can visit the property free of charge and produce an official report that puts pressure on the landlord.
- “**Never stop paying your rent, even if the landlord does not respond.** Only the justice of the peace can authorise a rent reduction or escrow. Unpaid rent puts you in the wrong.
Week-by-week timeline
Frequently asked questions
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They can raise this argument, but they must prove it. If the property has a structural defect (water infiltration, lack of ventilation, rising damp), the responsibility falls on the landlord. An inspection or expert report settles the matter.
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No, not on your own initiative. You must continue paying the full rent. You can ask the justice of the peace for a rent reduction or for the rent to be placed in an escrow account. Withholding rent on your own exposes you to proceedings for non-payment.
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If the work makes the property uninhabitable, the landlord must offer you a temporary solution or compensate you. In practice, most remediation work (mould treatment, ventilation) allows you to remain in the property.
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Mould can cause allergies, asthma, respiratory infections and skin irritation. If you experience symptoms, consult your doctor and ask them to certify the link with the property -- this document strengthens your case.
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