Pintail Water Treatment Plant Arsenic Treatment Improvements
Summary
SCH Number
2025101061
Public Agency
Yolo County
Document Title
Pintail Water Treatment Plant Arsenic Treatment Improvements
Document Type
NOE - Notice of Exemption
Received
Posted
10/22/2025
Document Description
The Wild Wings County Service Area (CSA) is a rural residential golf community located in unincorporated Yolo County, just outside the City of Woodland. The water system, managed by the County of Yolo, supports 338 residences and includes two existing groundwater wells that serve as the community's primary water supply. Installed in 2005, the system consists of the Canvasback and Pintail Well sites, two 360,000-gallon water storage tanks, a potable water distribution network, and a raw water conveyance system. The Canvasback Well has been on emergency standby since 2009 due to arsenic concentrations exceeding the State Maximum Contaminant Level (MCL). Currently, this well is limited to providing irrigation water through the raw water system. As a result, the Pintail Well is the sole provider of potable water for the community. In recent years, the Canvasback and Pintail Wells have experienced significant declines in groundwater levels. Arsenic levels in both wells continue to fluctuate.
The Pintail Water Treatment Plant (WTP) improvements were constructed to bring groundwater supplies into compliance with the State Water Resources Control Board—Division of Drinking Water (DWW) MCL for arsenic. The goal of the project is to enable the Canvasback Well to serve as an active production source by providing treatment at the Pintail WTP. The Pintail Well has historically remained below the MCL for arsenic, but the new facilities will also provide the capability to treat Pintail Well water if arsenic levels at that source rise above the standard in the future. As a result, the project ensures that either Canvasback or Pintail groundwater can be reliably used as a potable supply while meeting drinking water standards.
The Pintail WTP consists of two-skid mounted filter vessels and associated piping, valving, and controls; a 225-gallon sulfuric acid tank and chemical feed equipment for pre-treatment pH adjustment; a 225-gallon sodium hydroxide tank and chemical feed equipment for post-treatment pH adjustment; and a 16,500-gallon backwash tank. The arsenic treatment system treats water from the Pintail Well directly. It also has capacity to treat water from the Canvasback Well via the raw water line between the Pintail and Canvasback Wells. All improvements are confined to the previously disturbed and developed footprint of the existing Pintail pump station, which is surrounded by a CMU block wall and two access gates. No grading or land expansion occurred beyond the existing facility boundary. No new wells were drilled, no increase in water supply capacity occurred, and there are no changes to the overall operation of the water system other than the treatment of existing groundwater to meet DDW drinking water standards.
Pursuant to California Health and Safety Code Section 116275, a Public Water System (Community Water System) is required for the Wild Wings residential community. A Community Water System is defined in the Health and Safety Code as a “public water system that serves at least 15 service connections used by yearlong residents or regularly serves at least 25 yearlong residents of the area served by the system.”
Contact Information
Name
Yana Pavlova
Agency Name
Yolo County
Job Title
County Service Area Manager
Contact Types
Project Applicant
Phone
Name
Jeff Anderson
Agency Name
Yolo County Department of Community Services
Job Title
Principal Planner
Contact Types
Lead/Public Agency
Phone
Location
Coordinates
Cities
unincorporated area
Counties
Yolo
Regions
Unincorporated
Cross Streets
Pintail Street and Mandarin Street
Zip
95695
Total Acres
.33
Parcel #
025-440-072
State Highways
State Highway 16
Railways
none
Airports
Watts-Woodland Airport
Schools
none
Waterways
Cache Creek
Township
10N
Range
1E
Section
18
Base
MDB&M
Other Location Info
Located within Wild Wings residential community
Notice of Exemption
Exempt Status
Categorical Exemption
Type, Section or Code
Class 1; California Code of Regulations, Title 14, Section 15301
Reasons for Exemption
Section 15301 describes the class (Class 1) types for existing facilities, itemized below, where the project involves negligible or no expansion of use beyond that existing at the time of the lead agency’s determination. Pursuant to the requirements of CEQA Guidelines, Title 14 California Code of Regulations Section 15022(a)(1)(C), the California Department of Public Health has established a list of activities are that are categorically exempt from CEQA. Relying on said list, the County has determined the proposed project is categorically exempt from CEQA for the reasons set forth below:
(1) Continued operation and permitting of an existing drinking water supply including constructed water wells and surface water sources.
The Wild Wings residential community was developed in the early 2000s. To provide a reliable drinking water supply, the Pintail Well Pump Station was constructed and designated as a community water system by the State Water Resources Control Board – Division of Drinking Water (SWRCB-DDW). The station pumps groundwater to serve residential, commercial, and fire protection needs. It is enclosed by a CMU perimeter wall with two access gates and includes a 360,000-gallon storage tank, a 5,000-gallon hydropneumatic tank, and piping and fittings conveying water from the well to the distribution system. The current project includes improvements to the site through installation of a 500 gpm AdEdge arsenic treatment system, 16,500-gallon backwash tank, and pH chemical feed system.
(2) Continued operation and permitting of existing booster pump stations, generators, distribution pipelines, storage tanks and existing water treatment units including filters pumps and chlorinators.
Upgrades to the Wild Wings CSA community water system were completed in 2025 at the Pintail Well site. These improvements included installation of a 500 gpm AdEdge arsenic treatment system, 16,500-gallon backwash tank, pH chemical feed system, and related SCADA/PLC upgrades to address elevated arsenic levels in the groundwater. These upgrades do not expand groundwater extraction. The treated water supply continues to serve the Wild Wings CSA service area only.
(3) Interior and exterior alterations to the above listed appurtenances, which involve the addition, deletion, or modification of mechanical, electrical, hydraulic, monitoring, surveillance, security, remote sensing, and SCADA controls.
The addition of the 16,500-gallon backwash tank, 500 gpm AdEdge arsenic treatment skid, and pH chemical feed system, along with SCADA/PLC upgrades, does not represent an increase in use. The system continues to operate within the same approved capacity and service area as previously permitted by SWRCB-DDW.
(4) Additions to existing building structures and treatment plants, provided that the addition is within the existing confines of the property and will not result in an increase of more than:
(a) 50 percent of the floor area of the structure(s) before the addition, or 2,500 square feet, whichever is less; or
(b) 10,000 square feet
The combined footprint of the 16,500-gallon backwash tank, 500 gpm AdEdge treatment skid, and pH chemical feed system totals approximately 600 square feet. These improvements are located within the same parcel as the previous infrastructure and represent a negligible increase relative to the existing 13,000-square-foot facility area.
County Clerk
Yolo
Attachments
Notice of Exemption
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