Mängelanzeige: Formally Reporting Defects

Send a written defect notice with a repair deadline. After the deadline passes, you have a legal right to rent reduction (Mietminderung) under § 536 BGB.

✓ Verified: 15/07/2026

WHAT TO DO

Document the defect in writing and photograph it (EXIF date serves as evidence)

Send a written Mängelanzeige by registered mail (Einschreiben mit Rückschein) with a Fristsetzung (14–30 day deadline)
If not repaired by the deadline, reduce the rent. Case-law guide values: no heating in winter 20–100 %, mould 10–80 %, building noise 10–30 %, no hot water 5–20 %, lift 5–15 %
For serious defects or landlord refusal: contact the Mieterverein (tenants' association)

What is it and when to do it?

The Mängelanzeige is a written notice to the landlord about a defect in the apartment. Without it, no right to rent reduction arises. The process: notify → set a deadline → if ignored: reduce rent.

Step by step

Step 1: Document
Photograph and video the defect with a date stamp. Describe it in writing: what the defect is, where it is, when you discovered it, and how it affects your use of the apartment.

Step 2: Send the Mängelanzeige
Write to the landlord: defect description + Fristsetzung (a reasonable repair deadline, typically 14–30 days). Send by registered mail with return receipt. Keep the postal receipt.

Step 3: If the deadline passes
Your options: Mietminderung (proportional rent reduction), Selbstvornahme (arrange the repair yourself and deduct the cost from rent under § 536a BGB), Schadensersatz (compensation for losses), or in extreme cases extraordinary termination for good cause.

Mietminderung quick-reference

Defect	Reduction
Heating failure in winter	20–100%
Mould (partial room)	10–80%
Continuous noise (construction)	10–30%
No hot water	5–20%
Lift out of service	5–15%
Faulty windows / draught	5–10%

› Details and tips

👨🏻‍💻

Max recommends:

The heating failed in January. I called the landlord — promises, nothing happened. A week later I sent a registered letter with a 7-day deadline. The repair technician showed up the next day. The letter made it clear I was serious.

👩🏼‍💼

Lea recommends:

Never withhold the full rent — only reduce by the appropriate percentage. If the landlord disputes it, a court will determine the exact figure. A Mieterverein membership (from around €10/month) is worth it for exactly these situations.

FREQUENTLY ASKED QUESTIONS

By how much can I reduce my rent? ▾

Mietminderung is proportional to the reduction in usability of the apartment. Court benchmarks: heating failure in winter 20–100%, mould 10–80% depending on extent, continuous construction noise 10–30%, no hot water 5–20%, lift out of service in a high-rise 5–15%. The exact figure depends on the specific circumstances.

Does the notice have to be sent by registered mail? ▾

Any form that proves delivery is legally sufficient. However, registered mail with return receipt (Einschreiben mit Rückschein) is the strongest proof. Email is valid if the landlord explicitly replied to it. Personal delivery requires a witness or written acknowledgement.

Can the landlord evict me for applying Mietminderung? ▾

No, as long as the reduction is lawful: the defect is documented, the landlord was informed and the deadline has passed. An unlawful termination can be contested in court. Withholding more than one month's rent increases the risk — consult the Mieterverein if in doubt.