Reader question: From when can a requested higher flat-rate charge for operating costs be owed, and when is a mere new monthly figure not enough?
Your German rental agreement names an operating costs flat rate (Betriebskostenpauschale). The landlord is now demanding a higher monthly amount and at the same time money for past months. For a genuine flat rate the review according to §560 paragraphs 1 to 3 BGB is required. The rule for advance payments after an annual statement does not answer this question. [BGB560]
Secure the contract type first
Provide the full costs clause. Is a flat rate actually agreed or a monthly advance payment with settlement? Are individual costs regulated differently? The description on a standing order cannot replace the contractual content.
This article assumes a validly agreed operating costs flat rate. It does not assess whether a particular cost type must mandatorily be billed separately or whether an unclear contractual clause is effective at all. Such preliminary questions belong before a final determination of amounts.
Extract three statements from the declaration
§560 allows a pro rata allocation of increased operating costs if there is a corresponding contractual agreement. The declaration requires text form as well as designation and explanation of the reason for the allocation. [BGB560]
Therefore check separately the increase clause, the concretely named cost increase and the comprehensible share for your flat. A new figure with the heading “everything is more expensive” does not yet answer these points. Keep the declaration in full and note its date of receipt. If the calculation is unclear, request the missing explanation specifically, rather than merely writing a general “objection” in the subject line.
Distinguish start of the rule and retroactivity
In principle paragraph 2 names the beginning as the second month following the declaration. For actually retrospectively increased operating costs the provision contains a special route for retroactivity: at most up to the start of the preceding calendar year and only if declared within three months of becoming aware of the increase. [BGB560]
For an asserted retroactivity you therefore need additional data: when did the costs rise, when did the landlord learn of it and when was the declaration made? The invoice date alone need not answer each of these questions. An arbitrary difference that has lain dormant for years does not automatically become an owed flat-rate increase by virtue of the word “retroactive”.
Fictitious timetable with open question of retroactivity
An increase letter is received in October 2026. For the ordinary increase, where the other conditions are met, December 2026 is identified as the start. Additionally the letter demands differences since July. [BGB560]
The tenant treats this second demand as a separate point for examination. They ask for the alleged retroactive cost increase and the landlord’s knowledge. Only with these details can the special rule be examined. The dates are fabricated; the case confirms neither the amount nor the effectiveness of any particular declaration.
Also consider falling costs and economic efficiency
Paragraph 3 obliges, in the case of reduced operating costs, to a corresponding reduction of the flat rate from the time of the reduction and to immediate notification. The principle of economic efficiency and protection against disadvantageous deviations are also contained in §560. [BGB560] Thus a once agreed adjustment possibility is not a carte blanche for every new expense.
Present the requested change in a monthly overview: previous amount, alleged new amount, reviewed start and separately open retroactivity. This way the undisputed ongoing payment remains visible while the disputed change is professionally clarified. This overview does not decide on an unauthorised complete stoppage of payments.