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Emergency

Damp walls in the rental apartment: reduce the rent and clarify the cause

Damp walls or permanently high humidity are not just unpleasant, but often a defect of the apartment. The cause is decisive: if it lies with the building (e.g. rising damp, leaks), the landlord bears responsibility. If it lies solely with incorrect ventilation, things look different.

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Your chances of getting your money back

If the damp comes from a construction defect, the apartment is defective and the rent can be reduced (§ 536 BGB); in addition you are entitled to remediation.
If the landlord accuses you of incorrect ventilation or heating, it comes down to the cause. In a dispute, an expert opinion that determines the source helps.

What you should do now

  1. 1

    1. Document

    Photograph the damp spots with the date, measure the humidity if possible (hygrometer) and record since when the problem has existed.

  2. 2

    2. Record your ventilation behavior

    Note how you ventilate and heat. This removes the basis for the accusation of 'incorrect ventilation' and strengthens your position.

  3. 3

    3. Report the defect and set a deadline

    Report the defect to the landlord in writing with photos and set a deadline to clarify the cause and remedy it.

  4. 4

    4. Announce the reduction

    Announce a reasonable rent reduction and pay the rent under reservation until the cause is clarified.

  5. 5

    5. Consider an expert opinion

    If the cause remains disputed, an independent expert opinion can clarify whether there is a construction or usage error; in a dispute this is often decisive.

How to spot the scam

  • The landlord immediately blames your ventilation without having the building fabric checked.
  • The damp spots are simply painted over instead of remedying the cause.
  • Mold forms; then there is an additional health hazard.

Frequently asked questions

Who must prove where the damp comes from?

In principle the landlord must first show that the cause stems from your behavior (such as incorrect ventilation) if they rely on this. You should document your ventilation behavior. An expert clarifies disputed cases.

Can I reduce the rent even for only slight damp?

A reduction requires a noticeable impairment. For slight, short-term occurrences it is low or does not apply; for permanently damp walls it is considerably higher. The amount depends on the individual case.

What is the difference from mold?

Damp is often the preliminary stage; if mold forms, a health hazard is added and the reduction is regularly higher. In both cases the rule is: report, document, set a deadline.

Take action now

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General information for self-help, not legal advice (RDG). In case of a high loss or uncertainty: contact a consumer advice center or a lawyer.