Water sub-metering apartment buildings is a process of water measurement and billing by which water utility companies bill tenants, not individual water meters. Tenants use water from a common water supply line, but their water usage is billed separately from the landlord’s water bills.
Tenant water usage is separated into two types: inside and outside. Inside water usage can be further divided into hot water and cold water charges. If only one meter measures both inside and outside water usage, then it will have to be divided up by some other means such as fixed head type meters or flow meters with integral heads. The charging rates for tenant use are usually much higher than those for commercial establishments; therefore if there is no commercial component in the building (that would also be water sub metered), then water meters must be installed for both inside and outside water usage.
This method is considered more accurate than water sub metering commercial establishments because the water distribution system is common to every tenant, thus all water used by tenants can be measured with one water meter.
Since water meters are usually read manually, there may be a delay in reading the meter between billing periods. For example, an apartment building will have four different times of use billing periods per year. Meter readings are done quarterly for each bill period. An owner’s bill might not match what they are being billed if their meter was read at any time other than during the last week of the quarter month. Sometimes landlords are paying more or less depending on water meter readings.
Even though it is more accurate, water sub-metering apartment buildings may cause tenants to challenge their water bills, especially if the water usage on their bill does not match up with their water usage habits. A water sub meter outside of an apartment building will give a tenant an easier time monitoring their water use compared to inside water meters because they are usually read more frequently than inside water usage water meters (usually monthly or quarterly). This process of billing based on one water meter per common area can lead to incorrect readings of water used by all tenants, therefore increasing Tenant Water Bills and Finance Operating Expenses.
There are some pros and cons of submetering smaller residential properties or commercial establishments rather than water sub metering apartment buildings. A water meter for water sub-metering an apartment building would have to be shared by all tenants in the complex, thus water usage by individual tenants is not measured accurately. There are advantages and disadvantages of water sub metering commercial establishments rather than apartment buildings. Water meters for water sub metering commercial establishments are usually more accurate than water meters used for water sub metering apartment buildings that measure one common area shared with multiple units or different tenant types (residential vs commercial).
Water used by both residential and commercial users is not separated on the bill of a water sub meter, therefore it is very important for any water utility company reading water meters to determine which type of user each individual meter measures before billing accordingly.Water is generally billed in units of water usage, one unit being the equivalent of 10 cubic feet of water. This water sub meter billing method is used for water sub metering apartment buildings because many tenants are charged different rates for water usage. Then an average water use rate can be calculated by dividing the water bill amount by the number of units that have been billed to each tenant.