Document CO Alarms: Tenant Rights in Germany

Safety & Emergency Protections 3 min read · published September 07, 2025

As a tenant in Germany it is important to carefully document incidents involving a CO alarm. Good documentation protects your health and your tenant rights when readings are unusual or there is suspicion of a technical problem. This guide explains what information to collect, how to inform the landlord correctly and which deadlines to watch. I describe practical steps for photographing display readings, keeping a log and sending a formal defect notice. I also name relevant laws and administrative routes so you can act with legal certainty if necessary. The language stays accessible so non-lawyers can act quickly. Read the step-by-step guide below and use the links to official sources.

Why document CO alarms?

CO danger is acute: properly documented readings and timely contact with the landlord can prevent harm and are important for later tenancy claims. Documentation is both a safety measure and legal protection under landlord obligations in tenancy law.[1]

In most regions tenants are obliged to report technical defects.

What to document?

  • Photos of the CO alarm display with date and time visible in the image.
  • A short log with date, time, recorded values and circumstances (e.g. open windows, cooking).
  • All communications to the landlord in writing (email, registered mail) with sending date.
  • Invoices or contractor reports if repairs are carried out or required.
Detailed records increase your chances of success for rent reduction or compensation.

How to notify the landlord

Inform the landlord immediately in writing and request remediation. Use a clear defect notice, state date and readings and attach photos. Refer to your rights under the German Civil Code (BGB).[1] Send important letters by registered mail or by email with read receipt and keep copies.

Respond quickly because deadlines can affect your rights.

If the landlord does not respond

If there is no response, continue documenting and set a reasonable deadline for the landlord to fix the issue. If there is no remedy you may consider rent reduction, ordering an expert measurement or legal action. Court procedures follow the Civil Procedure Code (ZPO).[2]

An expert report helps to clearly prove cause and hazard.

FAQ

Who pays for a measurement or repair?
Generally the landlord must pay for safety-related repairs unless the tenant caused the damage; check the provisions in the BGB.[1]
Can I reduce the rent if there is a CO problem?
Rent reduction is possible if living quality is impaired and the landlord does not remedy it in time; document defects carefully and seek legal advice.
Which authority handles acute danger?
In acute danger call emergency services; for civil disputes the local court (Amtsgericht) handles tenancy matters, with appeals to higher courts.

How-To

  1. Gather evidence: photos, timestamps, a log of all readings and observations.
  2. Send a formal defect notice to the landlord by registered mail or by email with attachments.
  3. Set a deadline for remedy; if there is no response, consider rent reduction or legal action and obtain expert reports if needed.

Key Takeaways

  • Act quickly: timely documentation is crucial.
  • Keep evidence: photos and letters secure your legal position.
  • Use official channels: registered mail and clear defect notices.

Help and Support / Resources

  • Tenant advice hotline – Gesetze im Internet (BGB)
  • Legal information hotline – ZPO and court procedures
  • Justice ministry hotline – BMJ forms and guidance

  1. [1] Gesetze im Internet: Bürgerliches Gesetzbuch (BGB)
  2. [2] Gesetze im Internet: Zivilprozessordnung (ZPO)
  3. [3] Bundesministerium der Justiz (BMJ)
Bob Jones
Bob Jones

Editor & Researcher, Tenant Rights Germany

Bob writes and reviews tenant law content for various regions. They’re passionate about housing justice and simplifying legal protections for tenants everywhere.