Reporting a defect (Mängelanzeige): doing it right
If you do not report a defect, you may lose rent reduction, damages and the right to terminate without notice.
Checked by Radif Partners · Editorial policy · Method
What each week without a fix costs
Reduction for 21 days
€96.53
| Per month | €142.50 |
From the day the defect exists; without a report the right may be lost.
If a defect appears during the tenancy, a German tenant must report it to the landlord without delay (Section 536c(1) of the Civil Code). The same applies when a measure is needed to protect the flat against an unforeseen danger, such as a burst pipe, or when a third party claims a right to the flat. If you fail to report, you are liable for the damage that results. And as far as the landlord could not fix the problem because of that, you lose three rights: rent reduction (Mietminderung), damages under Section 536a, and termination without notice without first setting a deadline. The law prescribes no particular form, but a written report with date, description and photos is the safest proof. Every week counts: with gross rent of €950 and an assumed reduction rate of 15 per cent, 21 days are worth €96.53. A report is also the start of any solution, because only then must the landlord act.
Why the report carries so much weight
Tenancy law splits the duties clearly: the landlord must keep the flat fit for its agreed use, and the tenant must report defects he notices. The landlord does not live in the flat and would often not learn of damage otherwise. Section 536c BGB therefore attaches tough consequences to a missing report. A tenant who stays silent is liable for the damage his silence causes, for instance when a small damp patch spreads into mould. And as far as the landlord could not remedy the defect, he loses the rights the defect would otherwise give him.
What goes into the report
- Who and where. Your name, the address and the position of the flat in the building.
- What. A precise description: which room, which part, how large, since when. “Damp patch about 40 by 60 centimetres on the outer wall of the bedroom, visible since 5 January” beats “mould”.
- Evidence. Dated photos, measured temperatures for heating or hot water, a log with times for noise.
- Effects. How it limits your use, for example that a room cannot be heated.
- Deadline. A reasonable deadline for the repair, from a few days to a few weeks depending on urgency.
- Reservation. A note that from the appearance of the defect you pay rent only under reservation. That secures a later refund even if you keep paying in full at first.
What a late report can cost
The reduction applies by law as soon as the defect impairs the flat's use (Section 536 BGB). If the landlord could not remedy it for lack of a report, however, it lapses for the time in which he could have fixed it. The table shows what that means for gross rent of €950 and an assumed rate of 15 per cent. No statute sets the rate itself; it depends on how serious the defect is.
| Period | Days | Reduction |
|---|---|---|
| from 5 January 2026 | 7 | €32.18 |
| from 5 January 2026 | 21 | €96.53 |
| from 5 January 2026 | 60 | €289.60 |
The rent reduction calculator works this out for your own rent and period. Why there is no reliable table for the rate and how the reduction works is explained on the rent reduction page.
Defects that existed when you moved in
For defects you knew of when signing there is no reduction and no damages (Section 536b BGB). If you did not know of them through gross negligence, only if the landlord fraudulently concealed them. And if you take over a defective flat knowing of the defect, you must reserve your rights at the handover. That is why a detailed handover record with all visible damage, meter readings and photos pays off. It protects you at move-out too, when the deposit refund is at stake.
Damages and self-help
Besides the reduction, a tenant can claim damages if the defect existed when the lease was signed, arises later from something the landlord is responsible for, or if the landlord is in default with the repair (Section 536a(1) BGB). A typical case is furniture damaged by water from a known but unrepaired pipe. The tenant may fix the defect himself and claim the costs if the landlord is in default or the immediate repair is necessary to preserve the flat. In both cases the prior report is what puts the landlord in default in the first place.
Shared areas and neighbours
Defects outside the flat can affect it too: a broken lift, a damaged front door, heating failing for the whole building. Report them as well, even if you assume others already have. Several reports do no harm; a missing one can. For noise from neighbours the landlord is the right person to tell, because he can act against the disruptive tenant. For heating failure, water damage or a power cut in the whole building, the property manager usually has an emergency number; use it and still send the written report afterwards so the date and content are on record.