Mietkaution: The Rental Security Deposit
Maximum three months' net rent. The landlord must hold it in a separate account and return it within 6 months of moving out.
WHAT TO DO
What is it and when to do it?
The Mietkaution is a security deposit that protects the landlord against damage or unpaid rent. Its maximum amount is set by law (§551 BGB): no more than three net cold rents. It is paid before or on move-in and can be split into three instalments.
Where and how much does it cost?
Pay by bank transfer to the landlord’s account, or use a specialist product (Mietkautionskonto or Mietkautionsbürgschaft — a surety bond instead of cash). A surety costs around 3–5% of the deposit per year but avoids tying up your savings.
Common mistakes
Paid the deposit in cash without a receipt — at move-out the landlord claimed to have received nothing. Court proceedings, lost time and stress. Always transfer by bank: your bank statement is your proof.
The landlord hadn't returned the deposit after 8 months, citing 'ongoing checks'. It turned out the money was not in a separate account — which is illegal. Sent a formal demand letter with a deadline, and the money arrived two weeks later.
FREQUENTLY ASKED QUESTIONS
What is the maximum amount a landlord can charge? ▾
Under §551 BGB the deposit may not exceed three net cold rents (Nettokaltmiete, excluding service charges). At a cold rent of €900 the maximum deposit is €2,700. The landlord is legally required to hold the money in a separate, interest-bearing bank account.
Can I pay the deposit in instalments? ▾
Yes — this is a statutory right under §551 BGB. You can split the amount into three equal parts and pay them together with your first three monthly rent payments. The landlord cannot refuse.
How long does the landlord have to return the deposit? ▾
The law sets no fixed deadline, but courts consider 3–6 months after moving out to be reasonable. During that time the landlord checks the apartment's condition, waits for the final utility bill and raises any damage claims. After 6 months with no response, send a written demand.