Water Bill Calculations

How to Calculate Your Bill under the Water Rates Proposed for 2024:


Use our handy CUSTOMER BILL CALCULATOR (Excel)

or go step-by-step

  1. Determine your Service Type (Customer Class), Location (Inside or Outside City), and Service Size.
  2. Find the Bimonthly Fixed Service Charge for your Service Size in the 1/1/2024 column of that rate table (or the Fire Services table if applicable).
    • All Water Rate Tables displayed at the bottom of this page are included in the mailed Special Notice (PDF).
  3. Estimate the Units (1,000 gallons) of water that your account uses bimonthly (in two months).
  4. Calculate your Water Quantity Charge by multiplying your Units by the applicable Cost Per Unit in the 1/1/2024 column for your Customer Class and Location (Inside or Outside City).
    • For Single-Family Residential accounts:  Multiply each Tier of Units by its Cost Per Unit and sum those results to get your total Water Quantity Charge.
  5. If your account is in a Pumped Zone as shown on the Elevation Surcharge Map (PDF), calculate your Elevation Surcharge by multiplying your Units by $2.46.
    • Applicability of this Surcharge may be found on your most recent bill and in our Water Account Details (PDF) list sorted by Service Address.
  6. Add your Bimonthly Fixed Service Charge, Water Quantity Charge, and Elevation Surcharge (if applicable) to calculate your total Bimonthly Bill.
    • Subtract $25 if you are a single-family residential customer enrolled in the RateShare Discount Program.
    • Fire Services pay their Bimonthly Standby Charge only. They have no Water Quantity Charge or other charges.

To estimate bills for later years, use the appropriate column in the rate tables (e.g., 10/1/2027) instead of 1/1/2024.

NOTE: The City of Napa bills water customers bimonthly (every two months). To estimate your monthly water costs to compare with other utilities, simply divide your total Bimonthly Bill in half.

Sample Bill Calculations:

SINGLE-FAMILY RESIDENTIAL - INSIDE CITY - 1-INCH SERVICE,  BIMONTHLY USAGE = 3 UNITS

Bimonthly Fixed Service Charge = $52.04

Water Quantity Charge = 3 Units x $5.46 = $16.38

Bimonthly Bill = $52.04 + $16.38 = $68.42

SINGLE-FAMILY RESIDENTIAL - INSIDE CITY - 3/4-INCH SERVICE,  BIMONTHLY USAGE = 16 UNITS

Bimonthly Fixed Service Charge = $52.04

Water Quantity Charge = (14 Units x $5.46) + (2 Units x $8.05) = $92.54

Bimonthly Bill = $52.04 + $92.54 = $144.58

SINGLE-FAMILY RESIDENTIAL - OUTSIDE CITY - 3/4-INCH SERVICE - PUMPED ZONE,  BIMONTHLY USAGE = 43 UNITS

Bimonthly Fixed Service Charge = $52.04

Water Quantity Charge = (14 Units x $8.07) + (13 Units x $11.53) + (16 Units x $12.72) = $466.39

Elevation Surcharge = 43 Units x $2.46 = $105.78

Bimonthly Bill = $52.04 + $466.39 + $105.78 = $624.21

MULTI-FAMILY RESIDENTIAL - INSIDE CITY - 2-INCH SERVICE,  BIMONTHLY USAGE = 104 UNITS

Bimonthly Fixed Service Charge = $156.51

Water Quantity Charge = 104 Units x $7.59 = $789.36

Bimonthly Bill = $156.51 + $789.36 = $945.87

COMMERCIAL - INSIDE CITY - 4-INCH SERVICE,  BIMONTHLY USAGE = 91 UNITS

Bimonthly Fixed Service Charge = $479.39

Water Quantity Charge = 91 Units x $7.58 = $689.78

Bimonthly Bill = $479.39 + $689.78 = $1,169.17

IRRIGATION - OUTSIDE CITY - 1 1/2-INCH SERVICE - PUMPED ZONE,  BIMONTHLY USAGE = 331 UNITS

Bimonthly Fixed Service Charge = $99.53

Water Quantity Charge = 331 Units x $11.27 = $3,730.37

Elevation Surcharge = 331 Units x $2.46 = $814.26

Bimonthly Bill = $99.53 + $3,730.37 + $814.26 = $4,644.16

FIRE SERVICE - 8-INCH SERVICE

Bimonthly Fire Service Charge = $534.25

Bimonthly Fixed Service Charge

All Customer Classes (excluding Fire Services)

Service Size1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
3/4-inch meter
$52.04
$58.28
$63.53
$69.25
$74.79
1-inch meter
$52.04
$58.28
$63.53
$69.25
$74.79
1 1/2-inch meter
$99.53
$111.47
$121.51
$132.44
$143.04
2-inch meter$156.51
$175.29
$191.07
$208.26
$224.92
3-inch meter
$308.45
$345.46
$376.56
$410.45
$443.28
4-inch meter$479.39$536.92$585.24$637.91$688.94
6-inch meter
$954.22$1,068.73$1,164.91$1,269.75$1,371.33
8-inch meter$1,713.95$1,919.62$2,092.39$2,280.71$2,463.16


Water Quantity Charge

Single-Family Residential Customers: Inside City ($ cost per unit, unit = 1,000 gallons)

Tier of Usage1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
0-14 units$5.46
$6.12
$6.67
$7.27
$7.85
15-27 units$8.05
$9.01
$9.82
$10.71
$11.56
28+ units$9.77
$10.94
$11.92
$13.00
$14.04

Single-Family Residential Customers: Outside City ($ cost per unit, unit = 1,000 gallons)

Tier of Usage1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
0-14 units$8.07$9.03
$9.85
$10.73
$11.59
15-27 units$11.53
$12.91
$14.08
$15.34
$16.57
28+ units$12.72
$14.25
$15.53
$16.92
$18.28

Multi-Family Residential Customers ($ cost per unit, unit = 1,000 gallons)

Location1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
Inside City
$7.59
$8.51
$9.27
$10.11
$10.91
Outside City
$11.17
$12.52
$13.64
$14.87
$16.06

Commercial/Industrial/Institutional Customers ($ cost per unit, unit = 1,000 gallons)

Location1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
Inside City
$7.58
$8.49
$9.25
$10.08
$10.89
Outside City
$11.10
$12.44
$13.55
$14.77
$15.96

Irrigation Customers ($ cost per unit, unit = 1,000 gallons)

Location1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
Inside City
$7.65
$8.57
$9.34
$10.19
$11.00
Outside City
$11.27
$12.62
$13.76
$15.00
$16.20


Elevation Surcharge

Pumped Zone Customers ($ surcharge per unit, unit = 1,000 gallons)

Location1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
All Pumped Zones$2.46
$2.75
$3.00
$3.27
$3.53


Fire Services

Bimonthly Standby Charge

Service Size1/1/2024
10/1/2024
10/1/2025
10/1/2026
10/1/2027
1 1/2-inch
$33.99
$38.07
$41.49
$45.23
$48.85
2-inch
$51.64
$57.84
$63.04
$68.72
$74.21
2 1/2-inch
$75.21
$84.24
$91.82
$100.08
$108.09
3-inch$98.73
$110.58
$120.53
$131.38
$141.89
4-inch
$151.70
$169.90
$185.20
$201.86
$218.01
6-inch$298.83$334.69$364.81$397.64$429.46
8-inch
$534.25$598.36$652.21$710.91$767.78
10-inch$710.81$796.11$867.76$945.85$1,021.52
12-inch
$997.72$1,117.45$1,218.02$1,327.64$1,433.85