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Got a Nebenkostenabrechnung in hand? Check it in five steps: the two 12-month deadlines kept apart, the four mandatory formal details, the 17 chargeable cost types under the BetrKV, the allocation key, and the 15% heating-cost reduction – plus an interactive plausibility checker with no file upload.
Once a year it lands in your mailbox: the German operating-cost statement, the Nebenkostenabrechnung. Usually in the second half of the year, often ending in a back-payment. And nearly always it raises the same question – is this actually correct? Advice centres are blunt about it: by the recurring estimate of the German Tenants' Association (Deutscher Mieterbund), roughly one in two statements is flawed. The good news: you don't need a law degree to catch the most common errors. You just need an order of operations – and that is what this article gives you.
If you're in a hurry, enter your line items directly into the checker below. It sorts each item against the statutory catalogue and shows you how much is realistically disputable. How the review behind it works – and where its limits are – follows in the rest of the article.
Enter the billed items — no file upload. The checker compares each one against the German BetrKV catalogue and shows how much is realistically disputable.
Total of your monthly advance payments over the billing period.
If heating is not billed by measured consumption, you may cut your heating share by 15% (§ 12 HeizkostenV).
Not chargeable
€120.00
1 items the landlord may not pass on.
To check
€0.00
0 items that are often disputed or require a specific contract clause.
Chargeable
€550.00
2 items that are broadly in order.
Credit
€110.00
Billed balance on €670.00 total costs.
Adjusted Credit
€230.00
After deducting €120.00 of clearly disputable items.
A plausibility estimate based purely on the categorisation you enter — not legal advice and not an audited statement.
The most common misconception about operating costs concerns the deadlines. There are in fact two of them, both lasting 12 months – but they start on different days and cut in different directions. Many guides throw them into one pot; that is exactly what leads to wrong conclusions.
The first deadline binds the landlord: they must send you the statement "no later than the end of the twelfth month after the end of the billing period" Quelle. If your landlord bills by calendar year, the 2025 statement must reach you by 31 December 2026. Miss that, and the landlord generally loses the back-claim – unless they are not responsible for the delay. Importantly and pleasantly: a credit from a late statement still stays yours. The deadline only cuts against the landlord, never against you.
The second deadline is your own: you must raise objections against the statement "no later than the end of the twelfth month after receipt of the statement" Quelle. The anchor here is not the calendar year but the day the statement arrived. After that, your objections are generally late – again subject to the "not responsible" exception.
| Deadline | Who it binds | Starts | Length | Consequence of missing it |
|---|---|---|---|---|
| Billing deadline | Landlord | End of billing period | 12 months | no more back-claim |
| Objection deadline | Tenant | Receipt of statement | 12 months | objections are late |
Landlord deadline
12 months
from end of billing period
Tenant deadline
12 months
from receipt of the statement
flawed statements
≈ 50%
estimate, Deutscher Mieterbund
You can't have these deadlines "negotiated away" in your tenancy agreement either: any clause that deviates to the tenant's disadvantage is void. For everyday use, remember just one thing: if the statement comes late, you usually don't have to pay; if you want to object, you have a year from receipt.
Before you dive into individual amounts, it pays to look at the form. There's a strong lever here: if one of the mandatory formal details is missing, the statement is formally invalid – and a back-payment based on it is not due in the first place. That is different from a substantive error, where only a single item is wrong.
By the settled case law of the German Federal Court of Justice (BGH), an operating-cost statement for a building with several units must contain at least these four components (leading case: BGH, judgment of 19 November 2008 – VIII ZR 295/07):
Which cost type cost how much in total – for the whole building, not just for you.
By which measure is it distributed (floor area, occupants, consumption)? The key must be named and traceable.
How does your specific amount follow from the total costs and the key?
The advance payments you made over the year must be deducted.
A simple test does the job in practice: can you work it out on a sheet of paper, from the total costs via the key down to your amount, without having to guess? If yes, the form is met. If you have to speculate somewhere because a figure is missing or left unexplained, that's a formal defect.
The standard behind it is simple: you must be able to follow the statement conceptually and arithmetically. If you can, it is formally valid – whether the individual amounts are then also correct in size is a second question (the question of substantive correctness). If, on the other hand, one of the four building blocks is missing, it already fails on form.
Now to the heart of it: the individual items. The decisive point is that the German Operating Costs Ordinance (BetrKV) exhaustively governs which cost types are chargeable at all. The catalogue in § 2 BetrKV comprises exactly 17 items Quelle:
Whatever is not on this list is not chargeable either. Three classics keep appearing on statements without justification:
Watch out for item 17 ("other operating costs"): it is no blank cheque. Such costs must be specifically named in the tenancy agreement – a blanket clause "and other operating costs" is not enough by the prevailing view. Garden maintenance (no. 10) and the caretaker (no. 14) are chargeable in principle but often disputed: for the caretaker, any management or repair share must be stripped out. These are exactly the items the checker above flags amber – "please check".
If the catalogue checks out, the distribution is next. The allocation key is tied to your tenancy agreement; the landlord cannot simply switch it unilaterally. If no key is agreed in the contract, the statutory fallback is the floor area Quelle. The comparison is worthwhile: if the statement uses a different key than the contract – say suddenly "by occupants" instead of "by area" – that's a concrete starting point.
In practice you'll mostly meet four allocation keys: by floor area (the most common, easy to verify), by number of occupants (dispute-prone, since household sizes change over the year), by residential unit (each flat carries the same, regardless of size) and by consumption (for water and heating with their own meters). What matters for you above all: the key used on the statement must match what the contract says. If it changes from year to year for no visible reason, or deviates from the contract, that's a point for inspecting the receipts. A plausible reason for a switch would be the later installation of meters – then billing must be by consumption.
The biggest single lever often sits in the heating costs. Under the Heating Costs Ordinance, at least 50% and at most 70% of the costs of the central heating system must be distributed by actually measured consumption; the rest by area Quelle. In plain terms: your flat should as a rule have meters or heat-cost allocators, and your consumption must shape the statement.
If billing is not consumption-based – for instance everything flat by square metre – the law hands you a sharp lever: you may cut your heating share by 15% Quelle. That is exactly what the checker computes: set the heating billing to "flat rate / by floor area" and it deducts 15% of your heating items as a possible reduction. (There are narrowly defined exceptions for certain well-insulated older buildings – but those are the special case, not the rule.)
Take a typical statement: €340 water, €210 heating, €120 "property management", plus €540 advance payments over the year. On the face of it there's a back-payment of €130 (€670 total costs minus €540 in advances). It gets interesting on a closer look: the €120 "property management" is not chargeable and drops out entirely. If the heating was also billed flat instead of by consumption, add 15% of €210 – €31.50 – as a reduction. Together that's roughly €151.50 you can rightly challenge – more than the back-payment demanded. So the €130 back-payment effectively falls to zero, in this example even into a small credit. Precisely this gap between billed and adjusted balance is what the checker above makes visible – you only have to enter the amounts.
The amounts in the example are deliberately round. In practice it pays to go through every line of your statement one by one and pick the matching cost type in the checker. The more precise the mapping, the more solid the estimate – and the more concretely you can argue with the landlord later.
Spotted an item that doesn't fit? Then it's time to act. Your legal tool is called an "objection" (Einwendung, § 556 (3) BGB), colloquially usually "Widerspruch". Four things matter:
And the most common practical question: pay first or withhold? If the statement is formally valid and only individual items are disputed, the back-claim is due. Advice centres then recommend paying under reserve – transferring on time but expressly noting: "payment is made under reserve of reclaim after review". That preserves both the due date and your right to reclaim. If the statement is formally invalid (Step 2), the back-payment isn't due anyway – then you don't need this reserve.
An honest answer up front: there is no serious blanket figure for how much you get back "on average" – the numbers doing the rounds should be treated with caution. Your saving simply depends on the specific error. A wrongly charged management item might cost €80, a misallocated repair several hundred, and the 15% heating reduction can weigh heavily when energy prices are high. The adjusted balance in the checker gives you a first ballpark for that.
More important than the individual refund is the routine: whoever goes through their statement year after year by the same five steps catches errors that otherwise quietly add up – and signals to the landlord that someone is looking closely.
An everyday example: if a wrongly distributed item runs through a building for years, every tenant pays a few euros too much year after year. Over a four- or five-year tenancy that easily adds up to a three-figure amount – just because nobody questioned the line. The 15 minutes of checking per year are thus one of the best-paid quarter-hours in the household. And even if everything was correct in the end, you then know it for sure instead of merely hoping.
Keep your checked statements together with the delivery receipts of your objections in one folder. If it does come to a dispute later, you'll have your reasoning and your deadline-keeping cleanly documented – which is often half the battle.
The landlord's billing deadline (12 months from the end of the period) and your objection deadline (12 months from receipt) are two different clocks. Confuse them and you easily miss your own.
"Property management", "maintenance", "repair" – those words on the statement are a direct red flag. They don't belong there.
If meters are missing or everything is distributed by area, a 15% cut is on the table. Many tenants leave this lever unused.
An all-round objection without reasons has no effect. Name concrete items with a reason.
You're allowed to see the receipts. Whoever pays blindly gives away the strongest checking tool.
Once your statement is checked, it's worth looking ahead: how much rent realistically fits your budget is best worked out calmly – and operating costs are an item many underestimate. And when the next flat comes up, a complete search profile helps you react quickly.
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