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Rent reduction for mold: court rulings and percentages

In 14 rulings in our table, courts allowed a rent reduction of 7 % to 100 %. How much depends on how far the defect restricts the use of the apartment.

Updated: October 2026 · 119 court rulings

Typical reduction by severity

Minor

10 %

median of 6 rulings

Small mold spots, single area, e.g. bathroom or window area

Moderate

23 %

median of 4 rulings

Mold in living areas, multiple spots, musty smell

Severe

78 %

median of 4 rulings

Large-scale mold, health risk, multiple rooms affected

Median reduction rates of the court rulings in our rent reduction table, per severity level. The figures update with every new ruling; individual cases may differ.

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14 rulings found

Defect: Mold?

Create a free defect notice with a rent reduction demand — backed by these court rulings.

Reduce rent
DefectReductionDescription
100 %Health hazard from toxic mold spores; children needed emergency treatment
80 %Entire apartment permanently damp, musty and infested with mold
75 %Mold in every room of a newly built apartment at first occupancy
50 %Severe mold in the living room; 60% of the living space affected
30 %Mold from thermal bridges in the kitchen, bedroom and children's room; landlord did not disprove a structural defect
25 %Mold because the landlord did not give adequate ventilation instructions
20 %Damp and mold in the living room, bedroom and kitchen with a musty smell
15 %Several square meters of mold on the exterior wall above the window and along the skirting boards in the bedroom
10 %Mold on the exterior wall of a storage room
10 %Mold on window reveals in the children's room and bedroom caused by thermal bridges
10 %Airing the apartment six times a day to prevent mold is unreasonable for the tenant
10 %Airing 6 to 8 times a day to prevent mold is unreasonable
10 %Mold in the bedroom due to missing insulation of the top-floor ceiling
7 %Black mold on the silicone joints of the windows