In the past, multi-family communities had one master city water meter which would service all residents. The water and sewer costs were simply included in the monthly homeowners dues and divided equally among the residents. This worked well when water/sewer rates were a fraction of what they are today and possible future water shortages was not a concerning issue. Sub-Metering is a term used for installing individual meters behind the city master meter. Sub-Meters are the same type of meters the city uses to measure water usage.