A surprise utility back-payment (Nebenkosten)

These bills are frequently wrong — you have a firm right to check before you pay.

1. Read the deadline and the total, but do not rush the transfer. You generally have time to review; paying instantly forfeits nothing but makes a dispute harder.
2. Demand Belegeinsicht — the right to inspect the receipts. Ask the landlord in writing to see the underlying invoices and meter readings. Unexplained jumps are your signal.
3. Check the basics: your correct occupancy period, a sensible allocation key (Umlageschlüssel), and that only allocatable costs appear — some upkeep and management costs may not be passed to you.
4. The landlord has a deadline too. A settlement billed later than 12 months after the period usually cannot demand a back-payment — it can only refund you.
5. Object in writing within the objection window if something is off; keep it factual and itemised. Genuine errors get corrected often.

Rule for next time: set aside a little each month for the annual settlement, and keep your own meter photos from move-in and move-out.