Ancillary Cost Statement in Rental Agreements: Check Hidden Costs and Save Money

Imagine this: At the end of the year, you suddenly receive a high additional payment for ancillary costs – heating, water, caretaker – and you don't really know what the money was actually spent on. According to the 2026 Tenant Barometer, disputes over ancillary cost statements are among the most common problems for tenants.

Many contracts contain unclear flat rates, prohibited items, or omit a detailed breakdown. Good news: You can recognize the most important pitfalls just by reading the contract.

On welfarecalc.ch you can view all 30 risk points on ancillary costs completely free – without uploading a contract. We explain the most common pitfalls here as simply as if your 5-year-old self were listening.

Let's go!

1. Flat-rate ancillary costs without a detailed annual statement

📄 Original clause in the contract (common):
“A monthly flat-rate ancillary charge of CHF 250 will be levied. A detailed statement is waived.”

⚠️ Why is it dangerous? According to Art. 257a CO and Art. 4 VMWG, ancillary costs must be clearly listed in the contract and generally must be settled in detail annually (advance payment). Waiving the statement is usually inadmissible – you are entitled to transparency and a refund in case of overpayment.

🧒 Child-friendly explanation: It's like if you give 20 francs every month for the school fund but never find out what the money is really spent on – unfair and non-transparent.

✅ Correct: Ancillary costs as advance payments with a detailed annual statement based on actual consumption.

2. Ancillary costs not explicitly stated in the contract

📄 Original clause:
“Remaining operating costs or other ancillary costs will be charged additionally.”

⚠️ Why is it dangerous? Ancillary costs may only be paid if they are listed individually and specifically in the rental agreement. General wording like “remaining operating costs” is invalid – these costs are then included in the net rent.

🧒 Child-friendly explanation: The landlord can't suddenly say “oh yes, there are extra costs too.” Everything must be clearly written down beforehand, otherwise you don't have to pay it.

3. Repairs, replacements, or depreciation in ancillary costs

📄 Original clause:
“Repairs to the heating system and depreciation of the system are included in the ancillary costs.”

⚠️ Why is it dangerous? Repairs, replacement investments, and normal depreciation generally do not count as ancillary costs (exceptions for contracting or ZEV). The landlord must bear these costs.

🧒 Child-friendly explanation: If the heating breaks, it's like a broken school bus – the driver (landlord) has to fix it, not you with your lunch money.

4. No or limited right to inspect receipts

📄 Original clause:
“The tenant has no right to inspect the receipts for the ancillary cost statement.”

⚠️ Why is it dangerous? You have a legal right to inspect all receipts upon request. Any restriction is invalid.

🧒 Child-friendly explanation: You can always ask “what exactly was my money spent on?” and see the receipts.

5. Excessive flat rate or automatic increase without justification

📄 Original clause:
“The ancillary cost flat rate will be automatically increased by 5 % annually.”

⚠️ Why is it dangerous? Flat rates must be realistic (average of previous years). Arbitrary automatic increases are abusive.

6. No regulation on the annual statement deadline

📄 Original clause:
“The ancillary cost statement will be provided without a fixed date.”

⚠️ Why is it dangerous? The statement must generally be provided annually (often within 6 months after the end of the period). If delayed, you can set a deadline and later challenge the statement.

🧒 Child-friendly explanation: The landlord cannot wait for years and then suddenly send a large bill.

🔍 You've now understood the most important ancillary cost pitfalls

With this knowledge, you can identify unfair clauses early, check statements correctly, and avoid unnecessary additional payments. If you have your actual contract (in German, French, or Italian), you can have it checked on welfarecalc.ch for free and 100% locally in your browser – completely anonymous and secure.

Tip: Always request detailed receipts and check the statement within 30 days. Use sample letters from the tenants' association.

📢 Share this article with friends who are looking for an apartment. This concludes our blog series on the most dangerous rental agreement clauses.

Stay informed. Stay protected.