Definition of a "submeter": A submeter is a meter that is downstream or after the utility's meter (main meter) and is used to measure the portion used by an individual tenant or homeowner in a multi-family, multi-unit park, dwelling, or building. A submeter could be a water meter, gas meter, electric or in some cases an energy or sometimes called a btu meter.
Regulations: There are standards, mandates, and regulations that cover the use and implementation of submeters. It is advised to check with each states requirements when adding a submeters.
California:
Meter Registration and Certification Process: Most submeters in California must have a current type approval from Weights and Measures at the time of installation. Registration and certification of the metes with the local county of the metering system must renew their registration annually. Recertification of submeters must be performed a minimum of every ten years. To do this the meters must be removed and delivered to Weights and Measures for testing. Meter installation must be performed exclusively by Service Agents (SA's) who are employed by a Registered Service Agency (RSA) licensed by Weights and Measures. Other rules and regulations are required by California. Other states vary in their requirements
Weights and Measures Regulations: Install "Type" approved meters, have them tested and certified by a weights and measures testing facility, install the meter within the current specifications setforth in the guidelines. Meters may be "Type" approved by either Nationally NCWM: http://www.mcwm.net/ntrp/cert_search or or California CDFA: http://www.cdga.ca.gov/dms/ctep.html. Both sites must be searched as many type approvals show on one location. Each state can vary on regulation but generally most states require submeters to be either NCWM or CTEP approved.
Water Meters: There are differences between certified "type" approved meters. Some are only available in certain sizes, some have installation restrictions such as horizontal installation only or indoor use only while others have temperature and flow range limitations. There are a wide variety of materials used for water meters including: bronze, brass, composite/hybrid, plastic and stainless steel to name a few. Each have their pros and cons. The most versatile meters can be installed horizontally, vertically, inverted, have high temperature ratings, wide flow range, maintain accuracy for the life of the meter, and high pressure ratings.
Remote Reading Meters: There are many options to read water, gas and electric meters. Many still use old technology such as a pulse output to a wired remote display or wired to a radio transmitter which in turn sends the signal to a collector. The latest technology includes meters being available with integrated radio, where wires are eliminated entirely and the meter read remotely through various connectivity options such as lorawan, or cellular.
