Recycled Water
About Recycled Water
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.
Customer Resources
- Monthly Recycled Water User Self-Monitoring Form
- Monthly Recycled Water Usage Log (JPEG) for hydrant usage in Carneros.
- Recycled Water Customers can view their recycled water usage on the AquaHawk website.
Bay Area Clean Water Agencies' Site Supervisor Training Videos
- Availability & Pricing
- Expanding Use
- Other Information
- Reports
- Uses for Recycled Water
- Vineyard Irrigation
Recycled Water Availability & Pricing
Currently, NapaSan provides recycled water along two main pipelines to the southeast and north of the Soscol Water Recycling Facility. Check the recycled water pipeline map (PDF) 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.
Recycled Water Rates for 2023
| Rate Type | 2023 Rate per 1,000 gallons |
|---|---|
| Standard Rate | $2.11 |
| Storage Rate (February-March) | $1.11 |
| Large Volume Rate (minimum 150 acre feet per year) | $1.77 |
Expanding the Use of Recycled Water
Recycled water can be an important resource in areas that are water-short. Recycled water use decreases the demand on potable, surface, and groundwater sources. In 2022, NapaSan updated the Recycled Water Allocation Policy (PDF), establishing priorities for recycled water users.
Treatment Plant Projects
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 allowed NapaSan to increase recycled water production from 2,000 acre feet to 3,700 acre feet per year.
New Pipelines
Construction of the 5-mile Milliken-Sarco-Tulocay (MST) Recycled Water pipeline was completed at the end of 2015 in partnership with NapaSan, 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.
Napa Sanitation District’s (NSD) Water Reuse Program
The Water Reuse Program helps NapaSan meet water quality regulations, but it also protects water resources. By producing recycled water for reuse, NapaSan 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.
Recycled Water Users Guide
The use of recycled water involves precautions to prevent cross-connection with potable water sources and usage guidelines to protect public health. NapaSan provides annual training and a Recycled Water Users Guide (PDF) to its recycled water customers to insure the proper use of this valuable resource. NapaSan also offers a Water Reuse Program video for user training.
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.
NapaSan works with NBWRA to coordinate and seek state and federal funding for recycled water expansion projects. To date, NapaSan has received over $4 million in state and federal grants.
Strategic Plan for Recycled Water Use
In 2005, NapaSan completed a Strategic Plan for Recycled Water Use (PDF) 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.
Annual Report
Each year, the District sends the Recycled Water Annual Report (PDF) 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.
Monthly Recycled Water Quality Reports
The most recent monthly reporting numbers on the constituents found in the District's recycled water can be found in the Recycled Water Quality Report archives.
Recycled Water Criteria & Uses
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. NapaSan’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.
Napa Valley Uses
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 for Vineyard Irrigation
The Strategic Plan for Recycled Water included a recommendation for expanded use of recycled water for vineyard irrigation. In order to provide grape growers with an unbiased source of information regarding important water quality parameters in regards to vineyard irrigation, the NapaSan sponsored a study by the University of California (UC). This report, the Suitability Study of Napa Sanitation District Recycled Water for Vineyard Irrigation (PDF), assesses recycled water quality and its long term impact on irrigated vineyards.
The study was also peer-reviewed and appears as an article in the journal California Agriculture. The UC researchers concluded that NapaSan's recycled water is suitable for vineyard irrigation and would not present salinity or toxicity issues. View the graph (JPEG) showing chloride levels in recycled water from 2015 to 2018. As of August 2, 2018, the most recent chloride sample was taken on July 29, 2018, and the chloride level was 165.6 mg/L.