This accumulation is applicable to the type evaluation, initial verification, subsequent verification and in-use inspection of cold water meters (hereinafter referred to as water meters). This procedure is applicable to water meters that measure clean water flowing through closed full pipes, including mechanical water meters, mechanical water meters equipped with electronic devices, water meters that work based on electromagnetic or electronic principles, and also applies to electronic auxiliary devices for water meters. The working temperature of water meters is mainly below 30℃.