CO Alarm Checklist for Tenants in Germany

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

Tenants in German high-rise buildings should carefully document CO alarms because CO danger can be life‑threatening and proof helps in disputes with the landlord. Note installation location, model, serial number, manufacturer details and the date of commissioning or battery replacement. Photograph the device and the installation, save emails and repair requests and keep a short event log for alarms. If devices are missing or maintenance is lacking, tenants should inform the landlord in writing and set deadlines. If the landlord does not respond, legal assistance can be useful; many cases are heard at the local court. This guide explains practical steps to help enforce rights and increase safety in German rental apartments.

What tenants should document

  • Installation location, model, serial number and manufacturer (evidence)
  • Photos of device, mounting, wiring and display (evidence)
  • Date of commissioning and battery change (deadline)
  • Emails, letters and confirmations sent to the landlord (form)
  • Log of alarms with time and observed conditions (evidence)
  • Contact details of craftsmen or property management and scheduled appointments (call)
Keep photos, emails and serial numbers together in one folder.

Landlord obligations and legal basis

Under the German Civil Code (BGB), the landlord is obligated to maintain the rental property; defects that affect safety must be remedied [1]. In disputes about defects or necessary measures, the Code of Civil Procedure (ZPO) governs proceedings, which often begin at the local court [2][4]. There is no uniform federal rule requiring CO alarms in all residential buildings; however, the landlord's duty to secure against hazards may apply when concrete dangers exist [1].

Inform the landlord in writing and set a reasonable deadline before considering further steps.

Forms and templates

For contacting the landlord, short clear letters are suitable. Templates from the Federal Ministry of Justice and Consumer Protection can be used, for example for defect notices or terminations [3]. Example: A short defect notice names the device, the date of observation, requests remediation within 14 days and documents measures already taken (photos, appointments).

Practical steps when a CO alarm is missing

If there is no functioning CO alarm, proceed systematically: document, inform the landlord, set a deadline, and if needed consider legal action. Keep all landlord responses and receipts for replacement devices or craftsmen.

When legal action makes sense

If the landlord does not respond or the danger is acute, rent reduction, self-help by the tenant, or litigation at the local court may be options. For lawsuits, the deadlines and rules of the ZPO apply [2]. Initial consultation with tenant advice or a lawyer can clarify whether an eviction suit or other measures are necessary [4].

FAQ

Is the landlord required to install CO alarms?
There is no nationwide obligation for CO alarms; however, the landlord may be required by the BGB to avert hazards if concrete risks exist [1].
What evidence helps in disputes with the landlord?
Photos, serial numbers, emails, written defect notices and an alarm log are usually decisive.
Where do I turn if the landlord does not respond?
First set a written deadline; then legal advice or recourse to the local court may be appropriate [2][4].

How-To

  1. Document device data, photos and alarm times (evidence).
  2. Send the landlord a written defect notice with a deadline (form).
  3. Set a clear deadline, e.g., 14 days, and note the date (deadline).
  4. Seek legal advice or contact the local court if no solution is reached (court).
Early documentation and deadline setting increase the chances of a quick resolution.

Help and Support / Resources


  1. [1] Gesetze im Internet - BGB §535
  2. [2] Gesetze im Internet - ZPO
  3. [3] BMJV - Sample forms
  4. [4] BMJV - Information on the court system (local court)
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.