Water Recycling at Napa Sanitation District 

Recycled water is wastewater effluent that has been further treated and disinfected to provide a non-potable (non-drinking water) water supply. Recycled water is safe and suitable for uses such as landscape irrigation and some industrial processes. Recycled water is widely used and accepted throughout the United States as an environmentally responsible way to conserve scarce and expensive water supplies. It has been successfully used in other communities in California and other parts of the country such as Arizona, Florida, Hawaii, Texas and Colorado. Recycled water is the fastest growing water supply in California.


recycled water spray

Uses for Recycled Water

 The California Water Recycling Criteria (encoded in Title 22 of the California Code of Administration) allow 43 specified uses of recycled water, including irrigation of all types of food crops, parks and schools, golf courses and landscaping. These criteria include different water quality requirements for different types of irrigation. The District’s recycled water meets the highest quality standard, “Unrestricted Use.”

In addition to crops and landscaping, the state’s criteria also outline recycled water use for industrial applications such as cooling towers and toilet flushing. In specific instances recycled water can also be used for groundwater recharge. California’s regulations are among the most stringent in the world and have been used as a model for many other countries’ guidelines and water reuse regulations.

In the Napa Valley, recycled water is used to irrigate golf courses, vineyards, landscaping, pastureland, parks, playing fields and a cemetery. Using recycled water for irrigation in place of potable or groundwater helps conserve water resources.



 Recycled Water Customers- View your recycled water usage here.


To get a Monthly Recycled Water Usage Log for hydrant usage in Carneros, email Dave Martin at dmartin@napasan.com.   

  Recycled Water Usage Log


Frequently Asked Questions about Recycled Water


Recycled Water Availability & Pricing

Currently, the Napa Sanitation District provides recycled water along two main pipelines to the southeast and north of the Soscol Water Recycling Facility. Check this map to see the areas where recycled water is currently available.

The price of recycled water is adjusted each year in January according to a formula based on the Consumer Price Index. The table below shows the recycled water rates for 2017 and 2018.

Rate Type

2018 Rate per 1,000 gallons
Peak period rates (April-November) $1.67
Intermittent non-peak rates (Dec., Jan., Feb.) $1.25
March rates $1.12
Must-pay contracts (minimum 150 acre feet during peak period, April- Nov.) $1.34
Monthly meter charge (incurred May-Oct.) $33.17



NSD’s Water Reuse Program/Recycled Water Users Guide/Annual Report 

The Water Reuse Program helps the District meet water quality regulations, but it also protects water resources. By producing recycled water for reuse, the District decreases the amount of treated wastewater that must be discharged to the Napa River. Because this recycled water can be used for irrigation in place of potable (drinking) water or groundwater, it also conserves water resources.

The use of recycled water involves precautions to prevent cross-connection with potable water sources and usage guidelines to protect public health. The District provides annual training and a Recycled Water Users Guide to its recycled water customers to insure the proper use of this valuable resource. The District also offers a Water Reuse Program video for user training.

Each year, the District sends the Recycled Water Annual Report to all its recycled water users. The report provides a summary of recycled water quality, breaks recycled water use down by use type, and also provides updates on the recycled water production and distribution system expansion.


Expanding the Use of Recycled Water

Recycled water can be an important resource in areas that are water-short.  The District is working with water users throughout Napa to identify areas where recycled water could replace the use of potable, surface or groundwater.  In 2011, the District adopted a Recycled Water Allocation Policy, establishing priorities for recycled water users.

At the treatment plant, major investments were made to expand the treatment process to accommodate increased recycled water demand and distribution in southern Napa County.  The sand filter system was expanded and an equalization basin was constructed to provide a constant flow of water to the filters and increase filter efficiency.  The recycled water pump station was expanded and enhanced to provide different pressures in the system and increase distribution capacity.  A dissolved air flotation (DAF) clarifier was built to increase treatment capacity.  Together, these projects will allow NSD to increase recycled water production from 2,000 acre feet to 3,700 acre feet per year.  

 Construction of the 5-mile Milliken-Sarco-Tulocay (MST) Recycled Water pipeline was completed at the end of 2015 in partnership with NSD, Napa County and local land owners. The MST pipeline was built to deliver 700 acre feet of water per year.

The 9-mile Los Carneros Water District (LCWD) Pipeline was also completed at the end of 2015 in partnership with the Los Carneros Water District.  The LCWD Pipeline was built to deliver 450 acre feet of water. 

All of these projects will contribute to reduced demand for groundwater and save potable water from being used for irrigation.  



Recycled Water for Vineyard Irrigation

The Strategic Plan for Recycled Water included a recommendation for expanded use of recycled water for vineyard irrgation. In order to provide grape growers with an unbiased source of information regarding important water quality parameters in regards to vineyard irrigation, the District sponsored a study by the University of California. This report, Suitability Study of Napa Sanitation District Recycled Water for Vineyard Irrigation, assesses recycled water quality and its long term impact on irrigated vineyards. The study was also peer-reviewed and appears in the journal California Agriculture (68(3):59-67. DOI: 10.3733/ca.v068n03p59. July-September 2014.). The UC researchers concluded that NSD's recycled water is suitable for vineyard irrigation and would not present salinity or toxicity issues.     


The last chloride sample was taken on September 9, 2018 and the chloride level was 186.6 mg/L.

Date posted: Friday, September 14, 2018


Monthly Recycled Water Quality Reports

The following are the most recent monthly reporting numbers on the constituents found in the District's recycled water:


July 2018 Recycled Water Data

June 2018 Recycled Water Data

May 2018 Recycled Water Data

April 2018 Recycled Water Data

March 2018 Recycled Water Data

February 2018 Recycled Water Data


December 2017 Recycled Water Data

November 2017 Recycled Water Data

October 2017 Recycled Water Data

September 2017 Recycled Water Data

August 2017 Recycled Water Data

July 2017 Recycled Water Data

June 2017 Recycled Water Data

May 2017 Recycled Water Data 

April 2017 Recycled Water Data

 March 2017 Recycled Water Data


 December 2016 Recycled Water Data

November 2016 Recycled Water Data

October 2016 Recycled Water Data

September 2016 Recycled Water Data

August 2016 Recycled Water Data

July 2016 Recycled Water Data

June 2016 Recycled Water Data

May 2016 Recycled Water Data

April 2016 Recycled Water Data

March 2016 Recycled Water Data



December 2015 Recycled Water Data

November 2015 Recycled Water Data

October 2015 Recycled Water Data

September 2015 Recycled Water Data

August 2015 Recycled Water Data

July 2015 Recycled Water Data

June 2015 Recycled Water Data

May 2015 Recycled Water Data

April 2015 Recycled Water Data


North Bay Water Reuse Authority

The North Bay Water Reuse Program (NBWRP) is a coordinated regional effort among a group of water and sanitation agencies in Sonoma, Marin and Napa Counties, organized as the North Bay Water Reuse Authority (NBWRA), to offset potable water demand by promoting water reuse for agriculture, urban and environmental uses.

NSD works with NBWRA to coordinate and seek state and federal funding for recycled water expansion projects. To date, NSD has received over $4 million in state and federal grants. 


Strategic Plan for Recycled Water Use 

In 2005, the District completed a Strategic Plan for Recycled Water Use that determines a recycled water planning approach through the year 2020. The Strategic Plan examines seven different strategies, ranging from recycling only enough water to meet NPDES permit conditions to recycling all water available.