Formal deadlines first, then line items: half of all errors are costs that may not be passed to tenants at all.
✓ Verified: 18/07/2026
WHAT TO DO
Nebenkosten are the second rent — several thousand euros a year on average. Checking takes one evening with the bill, the lease and last year statement side by side. You also have the right to inspect the original invoices behind every number.
Household electricity is usually not part of this bill: you sign that supply contract yourself, and no invoice inspection will ever catch the overpayment. If you have never switched tariff since moving in, you are still with the city’s default supplier — the most expensive one by definition.
I check in order: first the deadline (must arrive within 12 months of the period), then forbidden items, then the key against last year. Three passes in one evening with bill, lease and last year side by side.
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Lea recommends:
Your right is invoice inspection: see the ORIGINAL invoices behind the bill. Request in writing, and half the mysterious items get explained or vanish.
FREQUENTLY ASKED QUESTIONS
The bill doubled in a year — possible?▾
Check the allocation key and meter readings: a jump without tariff changes is the classic marker of an error or someone else usage in your bill. Sharp energy price rises happen but are verifiable.
What can legally go into the utility bill?▾
Only the 17 categories of the operating-costs ordinance: heating, water, waste, cleaning, lift, property tax, caretaker, building insurance. Repairs, management, bank fees — none of it is the tenant burden.
Must the statement show the allocation key?▾
Yes: a proper statement lists total costs, the allocation key and your share transparently. A missing or unintelligible key makes the statement formally challengeable. Absent an agreement, living space applies (§ 556a BGB).