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Calibration requirement for water and heat meters

Cold and hot water meters as well as heat meters and their components that are made for business purposes or maintained in a condition in which they can be used without special preparation must be calibrated / assessed for conformity.

Calibration / Conformity assessment

Water, heat and cooling meters are calibrated by the calibration authority or by state-certified testing laboratories. Many meter manufacturers and utility companies have state-certified testing laboratories. 

Marking for calibration / conformity assessment

The calibration authority or state-certified testing laboratories use the metrology marking to label water and heat meters as calibrated or as or assessed for conformity in accordance with the recognised quality management system outlined in European MID 2014/32/EU. 

Prerequisites for calibration / conformity assessment – calibration approval for meters

Meters that have to be calibrated must be of a type that is approved for calibration. The mark of a type approval is the approval symbol on the meter, e.g. national approval, EEC approval or EC type examination certificate with the registered symbols and numbers.

Calibration fees

As per the Gebührenverordnung zum Mess- und Eichwesen [German regulation on fees for metering and calibration], the calibration fees are statutory levies and therefore cannot be discounted, rebated or credited. The fees change according to the applicable regulation on fees. 

Calibration period

The period of validity for the calibration / conformity assessment is not infinite. The period of validity for cold water meters is 6 years. The period of validity for hot water and heat and cooling meters is 5 years. 

For example:

Cold water meters: Calibration period 6 years

Calibration 2017 Calibration period lapses on 31.12.2023 

Hot water meter or heat meter: Calibration period 5 years

Calibration 2017 Calibration period lapses on 31.12.2022 

This means that the water and heat meters must be re-calibrated or replaced by properly calibrated meters upon expiration of these periods at the latest. No separate request will be made for this. Utility companies have the option of extending the calibration validity by three years by means of a random sampling procedure. 

One reason the validity shall expire prematurely is if the meter does not observe the maximum permissible error tolerances after calibration, e.g. owing to water quality or if the metrology marking or seal is damaged.

Meter check

Anyone who can demonstrate a justified interest in the measuring accuracy of the meter can request that the owner of the meter apply to the authority responsible or a state-certified testing laboratory for a meter check. The meter check will determine if a meter approved for calibration observes the maximum permissible error tolerances and meets the other requirements for approval.

Procedure for random sampling

Procedure for random sampling to extend the calibration validity period for water meters, heat and cooling meters 

If random sampling test is to be conducted to extend the validity period of calibration, it must be presented to the authority responsible for the testing laboratories carrying out the sampling and the authority responsible for the place of use before sampling. The random sampling test must be conducted in good time before the validity of the calibration expires so that if the requirements are not met before the validity period of the calibration expires, all the meters/components of the batch can be removed. 

The random sampling test and selection of the meters/components to be tested may only be conducted by the responsible authority or a state-certified testing laboratory for water and/or heat meters under the direct supervision of the testing laboratory manager or his/her proxy. 

More detailed information is available upon request. 

Duties of the owner of the meters

The meters must be cleaned and properly prepared for calibration. Meters that must be calibrated must be taken to the place of testing by the owner or a person authorised by the owner. The calibration authority or state-certified testing laboratories will not remove or install the meters at the place of use or carry out repair work. They generally replace the water meters of utility companies before the expiration of the calibration validity period.

Further information on laws and regulations

• Mess- und Eichgesetz (MessEG) [German measurement and calibration act] 

• Mess- und Eichverordnung (MessEV) [German measurement and calibration ordinance]  

• Measuring instrument directives (MID)  

See also


  • Diehl MeteringBernhard SchulzeHead of test centers for measuring instruments for water and heat
    Phone +49 981 1806-307
    Fax +49 981 1806-325
  • Industriestraße 13 D - 91522 Ansbach
Diehl Stiftung & Co. KG © 2018