The water consumption item has already been billed. It is therefore clear: the meter used was no longer calibrated (geeicht) during the relevant period. The tenant party therefore considers all readings to be unusable. As the landlord you now need a concrete evidential review of the bill and a separately clarified further operation of the device.
Secure the existing facts unchanged
Record the affected device identifier, period, initial and final readings and the actually determined calibration status together. Secure any existing photos, service provider documents and inspection reports. A calibration issue will not be removed retroactively from the billing explanation.
Our editorial recommendation: Before any impending device replacement, clarify with technical and legal support which documents and, if necessary, which test are required for the dispute. Do not manipulate the device yourself for that purpose. A new invoice must not claim a previous test that never took place.
Read the earlier BGH decision with its evidential limit
In judgment VIII ZR 112/10 the BGH distinguished between calibrated and no-longer-calibrated meters: for the latter the factual presumption of correct values is lacking. The landlord must prove the correctness in the proceedings to the court's satisfaction. In that case a timely test report from a state-recognised testing body was successful. [BGH]
A private statement that the consumption looks normal is therefore not automatically the same proof. Likewise, a test report for another device or period does not answer the specific question without further attribution. Which basis suffices in the present case remains to be assessed technically and legally.
Rectify the statutory metering operation independently
The historical BGH judgment was issued before the current MessEG. The current §§ 31, 33 and 37 contain duties for lawful device and measurement value use; in particular meters must not be used uncalibrated after the expiry of the relevant calibration period. [GERAET, WERTE, EICHUNG]
The LG Limburg also distinguished, even after the MessEG came into force, the public-law duties from the civil-law consequences for a consumption statement. It denied an automatic comprehensive prohibition on the use of evidence. [LG] Neither a general permission to use nor a safe outcome of any current billing process is derived from that here.
Therefore organise the appropriate lawful further operation with the responsible service provider. An outstanding past bill should not lead to a known device fault simply being carried forward in the ongoing process.
Fictitious case: A settlement does not replace device testing
Mira receives a specific objection. She compares the consumption with the previous year and finds the order of magnitude plausible. Her previous draft reply therefore reads that the meter must have measured correctly.
She replaces this mere inference with an inspection order: which actually available proofs relate to exactly this device and the disputed period? In parallel she has the further operation of the device clarified. She submits the previous year’s values as available information, without declaring them themselves to be sufficient proof.
Base the billing approach on the test result
Let the agreement and the available proof decide how the specific item should be treated further. An arbitrary new area calculation or an automatic deletion of all water costs will not be derived solely from an untested buzzword.
The conclusion documents the decision on the disputed item, its basis and the separately clarified future metering operation. The article deals with the civil-law rental dispute; special rules of a municipal fee claim and current individual deadlines are not decided here.