Apply for Sewer Submeters

A submeter is commonly defined as either a deductible meter or a chargeable meter. The submeters are physically the same but differ in their installation and billing method.

A deductible meter is installed on the water line that supplies the allowable deduction and is read by SPU with the registered consumption subtracted from the customer’s sewer charges. In this type of installation, sewer is billed on all water used except for that measured through the submeter.

A chargeable meter is installed on a water line supplying a portion of the facility that does discharge to the sewer. This meter is also read by SPU with the registered consumption used as the basis for sewer charges.

Note: Certain types of equipment, including cooling towers, swimming and wading pools, require the installation of both a deductible and a chargeable meter. In these cases, a deductible meter will deduct water supplied to equipment from their sewer charges, while the chargeable meter will capture the percentage of water that is actually discharged to the sewer.

Most customers will only be authorized to install deduct meters to eliminate sewer charges for water that doesn’t enter the sanitary sewer system. Example: irrigation, water used in products and makeup feed water for cooling tower evaporation. When receiving a deduction on a cooling tower or other such equipment where there is discharge to the sewer, a charge meter is required on those drain lines.

• In rare cases where installing a deduct meter isn’t feasible, a chargeable meter may be authorized to capture actual effluent discharged from the property.
• Customers with a dewatering permit are required to have a chargeable meter installed to capture actual effluent discharged from the property to a sanitary or combined sewer system.
• All submeters must register in cubic feet, accurately capture all flow ranges, and remotely transmit meter reads to the city right-of-way using Encoder Receiver Transmitter (ERT) technology.
• There are several different ERT styles. A 100W E+ module should work with most installations. If you would like to purchase a module other than a 100W E+, you must get advanced approval from SPU.
• Most installations will require the ERT to be ordered in “hard to read” mode from the supplier.
• All chargeable submeters installed are required to be either an ultrasonic or electromagnetic meter unless specified otherwise on your individual site compliance plan.

• Submeters must measure in CF (cubic feet) and broadcast in CCF (100 cubic feet). Gallon meters are not allowed.
• Submeters must have an ITRON connector and the end of the wire with an ITRON 100W+ ERT connected.
• Order meters with potted wires at least 20 feet long (or long enough to reach the predetermined wiring location).
• Order ITRON ERT modules in “hard to read” mode from the supplier unless directed otherwise by your individual submeter compliance plan.
• The most current ITRON ERT compatibility list can be found online.

Submeter with ITRON connector

ITRON 100W+ ERT

Drains
An inverted P-trap keeps the meter flooded and prevents positive air pressure from created false consumption. These are required on all drain lines to prevent false registration of consumption on submeters installed on drain lines.

Cooling tower drain with inverted P-Trap