This Recommendation is applicable to the type evaluation and initial verification testing of water meters intended for the metering of cold potable water and hot water as defined in OIML R 49-1 [1]. OIML Certificates of Conformity may be issued for water meters under the scope of the OIML Certificate System, providing that the three parts of this Recommendation are used in accordance with the rules of the System. This Recommendation sets out details of the test program, principles, equipment and procedures to be used for the type evaluation and initial verification testing of a meter type. The provisions of this Recommendation also apply to ancillary devices, if required by national regulations. The provisions include requirements for testing the complete water meter and for testing the measurement transducer (including the flow or volume sensor) and the calculator (including the indicating device) of a water meter as separate units.