How Utility Bills Are Calcuated

Electric

Electric costs are based on customer usage. To calculate usage, refer to your utility bill and subtract the previous month's reading from the current reading. The difference is the electricity usage measured in kilowatt-hours (kWH) for that billing period. To calculate the electric cost, multiply the usage (kWh) by the rate and add the monthly facilities charge.

Example:
Previous reading: 1000
Current reading: 2000
2000-1000 = 1000 kWh (usage)
1000 kWh X $0.097077 (rate) = $97.08
$97.08 + $26.00 (facilities charge) = $123.08*
*Note: This total does not include the 7% sales tax or any of the billing credits offered through the Load Management Program.

Natural Gas

Natural gas costs are based on customer usage. To calculate usage, refer to your utility bill and subtract the previous month's reading from the current reading. The difference is the natural gas usage measured in cubic feet (CCF) for that billing period.
Natural gas usage is measured in CCFs (volume) but billed in therms (heat factor). To convert the usage from CCFs into therms, the city must first multiply the usage by the pressure factor and therm factor.

Pressure Factor: The normal delivery pressure of natural gas is 0.25 pounds per square gauge (psig), and the gas meters are calibrated based on this pressure. However, some customers' natural gas is delivered at a higher pressure due to requirements of the customers' natural gas appliances, equipment or piping. In order to ensure their gas usage is properly measured, a pressure factor must be applied to their bill. The pressure factor is based on the delivered pressure of the natural gas.

Therm Factor: Since natural gas meters measure volume and not energy content, a therm factor is used by the city to convert the volume of gas used to its heat equivalent, and thus calculate the actual energy use. The therm factor is usually expressed in units of therms per CCF. The therm factor is applied to all natural gas customers' utility bills. The value of the factor changes annually and appears on the utility bill under the “Multiplier/Factor” column.

To calculate the natural gas cost, multiply the usage (in therms) by the rate and add the facilities charge for that month.

Example:
Previous reading: 4270.00
Current reading: 4370.00
4370-4270 = 100 CCF (usage)
100 CCFs X 1.1312 (pressure factor) = 113.12
113.12 X 1.067 (therm factor) = 120.70 therms
10 X $1.11646 (rate) = $11.16 (for the first 10 therms)
120.70 - 10 = 110.70 therms X $0.85183 (rate) = $94.30
$11.16 + $94.30 + $14.00 (facilities charge Apr-Sep) = $119.46*
*Note: This total does not include the 7% sales tax or the Purchase Gas Adjustment (PGA).

Purchase Gas Adjustment (PGA): Natural Gas is a commodity traded on the open market and its price is based on supply and demand. In addition to buying natural gas on the open market, the city of Rocky Mount also pays to have it transported from the wellhead to the city. Rates are set using a base rate that accounts for transportation, commodity and utility costs. Based on the fluctuating price of the delivered natural gas, the city's rates may be adjusted each month using a rate mechanism called the Purchase Gas Adjustment (PGA). The city of Rocky Mount does not profit from the fluctuations in gas costs. Instead, all costs associated with increases or decreases in the commodity price of natural gas are passed along to customers. For example, if the PGA is -$0.30, then the residential gas sales rate is reduced by $0.30 per therm.
The current PGA is: $0.00.

Water

Water costs are based on customer usage. To calculate usage, refer to your utility bill and subtract the previous month's reading from the current reading. The difference is the water usage measured in cubic feet (CCF) for that billing period. To calculate the water cost, multiply the usage by the rate and add the monthly customer charge.

Example:
Previous reading: 5000.00
Current reading: 5003.00
5003-5000 = 3 CCF (usage)
3 CCF X $1.70 (rate for inside city limits) = $5.10
$5.10 + $9.00 (customer charge) = $14.10

Wastewater

Wastewater (sewer) costs are based on customer water usage. To calculate costs, multiply the water usage (CCF) by the wastewater rate and add the monthly customer charge.

Example:
3 CCF X $2.70 (rate for inside city limits) = $8.10
$8.10 + $9.00 (customer charge) = $17.10

Refuse

The refuse charge on your bill is for your rollout cart (waste collection) and recycling services. Customers are billed a monthly service charge for these utility services based on household type.

Example:
Rollout container disposal fee for residential occupancy: $10.75
Recycling fee for single-family household: $2.50
Refuse total: $13.25

Stormwater

Customers are billed a monthly service charge for stormwater based on the parcel type (e.g. single-family, duplex, multi-family). The charge is calculated by multiplying the rate by the Equivalent Residential Unit (ERU). One ERU is equal to 2,519 square feet of impervious area.

Example:
$5 (rate) X 1 ERU (single-family) = $5.00