Please Note! On July 1, 2018, capacity charges increased from $9,299 to $9,624.  This new rate will be in effect from July 1, 2018 through June 30, 2019.  


Rates and Fees

The Napa Sanitation District charges a fee for connection to the sewer system, and then charges an annual rate for sewer service. These rates and fees vary depending on the type of sewer service connection you have. Sewer service connections are classified as residential, commercial, or industrial.

Sewer Service Charges - Residential
Sewer Service Charges - Commercial
Sewer Service Charges - Industrial
Capacity Charges - Residential
Capacity Charges - Commercial and Industrial
Plan Check and Inspection Fees
Recycled Water Rates
Waste Hauler Rates


 Sewer Service Charges - Residential

The Sewer Service Charge (SSC) is the fee that customers are charged each year (billed annually or monthly) for collection and treatment of sanitary waste from their home or business.  The rate  is based on the typical volume and strength of the wastewater generated by a single family home, which is called an Equivalent Dwelling Unit (EDU).

2018/19 Sewer Service Charges (Beginning July 1st)


Type of Unit  Number of EDU  FY 2017-18*
Single Family Dwelling  1.0  $676.38
Duplex, each unit 1.0 $676.38
Condominiums and Townhouses   1.0  $676.38
Triplex, Fourplex & Apartments  0.6  $405.82
Mobile Home 0.6 $405.82
Overnight Trailer Park, per space 0.4 $270.56


*Fiscal years are from July 1 through June 30

 Click here to view historic Sewer Service Charges


What is an Equivalent Dwelling Unit (EDU)?

An Equivalent Dwelling Unit (EDU) is the typical volume and strength of the wastewater generated by a single family home.

One EDU = 210 gallons of wastewater per day or 76,650 gallons per year with a strength factor of 1.0.  


Sewer Service Charges - Commercial Businesses

Sewer Service Charges are charged annually, either on property tax assessments or directly billed to the commercial customer. The sewer service charge for commercial businesses is based on the following formula:

Amount of potable water (gallons) used in prior year ÷ 76,650 x strength factor x current rate per EDU

To understand this formula, 76,650 is the annual water use in gallons for an Equivalent Dwelling Unit (EDU). The Strength Factor is based on the State Water Resources Control Board Revenue Program Guide which calculates the typical strength for wastewater generated by various business types. A list of strength factors by business category can be found in Section 5.01.030 of the Napa Sanitation District Code, which can be viewed by clicking here


Sewer Service Charges for Unmetered Commercial, Public Utilities and Public Agency Facilities

Unmetered commercial, public utilities, public agency facilities and schools (both public and private) are charged as follows:

Elementary - 1 service unit (EDU) per 48 students
Secondary - 1 service unit (EDU) per 17 students
Other - 1 service unit (EDU) per 10 employees/occupants


Sewer Service Charges - Industrial Businesses

Industrial businesses, including winery-related operations, require a permit to discharge process waste to the sewers. Industrial users are charged monthly for sewer service based on the following formula. The formula is designed to provide a multiplier for high-strength flows. There is a minimum of 1.0 service unit. Biochemical Oxygen Demand in mg/L (BOD) and Total Suspended Solids in mg/L (TSS) are determined through the use of samplers:

 Step 1: Flow Factor
Flow Factor = Average daily flow (in gallons) ÷ 210 gallons/day

Step 2: Strength Factor
Strength Factor = 0.50 + (BOD ÷ 175 mg/L × 0.25) + (TSS ÷ 200 mg/L× 0.25)

Step 3: Calculate Equvalent Dwelling Units (EDU)
EDU = Flow Factor × Strength Factor

Step 4: Calculate Monthly Sewer Use Fee
Monthly Sewer Use Fee = EDU × Current Rate per EDU ÷ 12


Capacity Charges

The Capacity Charge (sometimes called a connection fee ) is the fee that the NapaSan charges when a new home or commercial tenant connects to the sewer system, or expands its impact on the system.

Capacity Charges - Residential

Capacity Charges for a single family dwelling are as follows: 
$9,624 - July 1, 2018 - June 30, 2019

Click here to view historic Capacity Charges.  

What is a dwelling unit?

NapaSan defines separate dwelling units to include a living space with a kitchen. Examples of dwelling units include but are not limited to  single family homes, condos, apartments, and duplexes. 

What is an Accessory Dwelling Unit (ADU)?

An ADU is a secondary dwelling with complete living facilities for one or more persons that can be attached, detached, or re-purposed existing space.

What are the capacity charges for an Accessory Dwelling Unit?

Capacity charges for ADUs are waived if the unit is under 499 sq. ft, and based upon square footage for all other units. Section 5.02.030 of the NapaSan Code lists the Capacity Charge assessments for different types of residential units.  View Section 5 of the Code here.  

Changes to Existing Residential Structures

Renovations within single family dwellings or multiple family dwellings will not trigger additional Capacity Charges, except where additional dwelling units are added to the property.

Capacity Charges - Commercial and Industrial


Please Note: 

Ordinance 101 was adopted by the Board on July 1, 2015.  This ordinance changed the way that capacity charges are calculated for restaurants and other commercial buildings.  This new Ordinance became effective on Monday, August 31, 2015. See Title 5 of the NapaSan Code for the formula used to calculate capacity charges for commercial and industrial customers.   



Plan Check and Inspection Fees

A permit fee is paid to NapaSan for issuing a permit and inspecting any work that adds to, alters or extends a sewer connection to an existing building.

Plan Check Fees:   

Residential Subdivision
Subdivision Review
Residential Lot Review

$414 per subdivision plus $104 per lot
Residential Lot without Mains     $104 per lot
Apartment Buildings $827 per building
Hotel Building $1,240 per building
Commercial Building $414 per building
Tenant Improvements - Food Service $310 per tenant unit
Tenant Iprovements - Non-Food Service $207 per tenant unit
Mainline Extensions - not part of a subdivision $104 per 100 linear feet of mainline extension, or portion thereof
Public Easement - not included in recorded map $104


Plan Check Fee includes two submttals for plan check. If additional submittals are required for approval, then fee is assessed again, and an additional two submittals are allowed.

Inspection Fees:
Below is the schedule of charges for inspections of sewer laterals, side sewers, and house, trunk, and main sewers. 


Public Lateral - Residential $185 per lateral
Private Lateral - Residential $185 per lateral
Public/Private Lateral - Commercial $368 per lateral
Mainline $368 per 100 linear feet of mainline, or portion thereof

Inspection fee includes one inspection and one re-inspection. If additional inspections are required for approval, then fee is assessed again for each additional inspection.

Recycled Water Rates


The price of recycled water is adjusted each year in January according to a formula based on the Consumer Price Index.   

Please review the District's Recycled Water Rates Ordinance for more details.

Current Recycled Water Rate:


                                                 2018                           2017                           

April through November
$1.67 per 1,000 gallons  $1.62 per 1,000 gallons 
January, February, December
$1.25 per 1,000 gallons $1.22 per 1,000 gallons
March $1.12 per 1,000 gallons $1.09 per 1,000 gallons
Monthly Meter Charge
May through October
$33.17 per month $32.22 per month


 Waste Haulers

Rates are set based on the volume and the type of waste.


Fats, Oil and Grease (FOG) Haulers

FOG is charged based on the volume delivered each month. The more FOG delivered each month, the lower the per gallon charge; monthly delivers of 50,000 gallons or more are free of charge. See the table below for current rates.

Gallons per Month of FOG Cost
2,500 or less $0.10/gallon
2,500 - 24,999 $0.07/gallon
25,000 - 49,999 $0.03/gallon
50,000+ Free