German law sits unexpectedly on the tenant’s side here: where a defect exists, the obligation to pay full rent falls away by operation of law. The argument is not about the right to reduce but about whether a defect exists and how serious it is.
What counts as a defect and why the reduction happens by itself
If the flat is less usable than it should be, by law the tenant owes only an appropriately reduced rent. No permission from the landlord is required.
✓ Verified: 01/08/2026
WHAT TO DO
› Details and tips
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Max recommends:
I spent a month arguing about whether I was allowed to reduce. The reduction had long since arisen by law — what needed arguing was the amount and the notification.
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Lea recommends:
Photograph the defect with a date, repeatedly rather than once. Mould developing over three weeks convinces more than any description.
FREQUENTLY ASKED QUESTIONS
What counts as a defect? ▾
A condition in which the flat’s contractual usability is reduced or absent: heating that does not heat, mould, water ingress, sustained heavy construction noise, a failed lift with no alternative. What matters is the departure from what you were entitled to expect.
Do I need permission to reduce the rent? ▾
No. The law says it directly: for the period during which usability is impaired, only an appropriately reduced rent is owed. That follows from the defect itself, not from any decision by the landlord.
Does every little thing qualify? ▾
No. The law expressly excludes trivial impairment. A dripping tap or one noisy evening will not do; this is about what genuinely obstructs use of the home.
What if the defect was known when I moved in? ▾
Then the right to reduce for that defect generally falls away: accepting the flat in a known condition means accepting it. That is why the handover protocol matters long after moving day.