There is mould or damp in my rental — who do I report it to?
Mould is a health matter as well as a repair. Report it to the landlord in writing with photos and ask for the cause to be found — a leak, missing insulation, no ventilation — not just for the wall to be repainted. If nothing happens, Schlichtungsbehörde in Mietsachen (ch.ch) decides rent reduction and orders repairs; Kantonales Amt für Umwelt / Wohnhygiene der Stadt (bafu.admin.ch) can inspect and declare the home unfit for habitation, which forces the landlord's hand. Mieterinnen- und Mieterverband (mieterverband.ch) advises on what you can deduct and how much rent you can withhold.
🗣️ What to say
"Since [date] there is mould in the [room] at [address], photos attached. It affects our health [symptoms if any]. Please have the cause investigated and repaired by [deadline]. Until then I reduce the rent by [%] from [date]."
🪜 Step by step
- Photograph and date itWide shots and close-ups, a ruler for scale, the humidity reading if you have a cheap meter. Repeat weekly.
- Ventilate and heatDocument that you do — landlords blame "lifestyle" first. Airing twice a day and heating to 18–20 °C removes that argument.
- Report in writingAsk for the cause to be found. A repaint without fixing the cause is not a repair.
- Inspection: Kantonales Amt für Umwelt / Wohnhygiene der StadtThe municipal or environmental health inspection visits, measures, and can order works or declare the home unfit.
- Tenancy body: Schlichtungsbehörde in MietsachenRent reduction backdated to the report, and an order to repair.
📇 All contacts
❓ Frequently asked
Is mould really the landlord's problem?
Mould caused by the building (cold bridges, leaks, broken ventilation) is. Mould caused only by never ventilating is the tenant's. The inspection decides which.
Can I leave without notice?
If the home is unfit for habitation and the landlord will not act, most countries allow termination without notice — get the inspection report first.
Can I claim for damaged belongings?
Yes, if the cause was the building and the landlord was notified. Keep receipts and photos; contents insurance may pay first and recover from the landlord.
📎 Sources
- Schlichtungsbehörde in Mietsachen →
- Kantonales Amt für Umwelt / Wohnhygiene der Stadt →
- Mieterinnen- und Mieterverband →
- Gemeindeverwaltung / Stadtverwaltung →
🔎 Common searches
Recognise your own search? The answer above covers all of these.
- “mould in rental landlord responsibility Switzerland”
- “damp flat rent reduction”
- “report mould housing inspection”
- “unfit for habitation tenant rights”
- “mould health landlord”
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