Capital Improvement Program
Coastside County Water District is committed to providing our customers with reliable, high-quality drinking water and services, while maintaining its facilities and infrastructure. The District’s Capital Improvement Program ($73 Million planned for fiscal years 2026/27 to 2035/36) ensures that the District’s infrastructure and assets are replaced at the end of their life cycle and upgraded to the most current state-of-the-art technology, as well as invest in future sustainable facilities and systems.
Commenced August 2026
Alcatraz Avenue and Santa Rosa Avenue Pipeline Replacement Project
This project will replace all existing domestic water lines on Alcatraz and Santa Rosa Avenue in the Miramar neighborhood. The work includes the installation of approximately 660 feet of 6-inch ductile iron pipe (DIP), new gate valves, and new water service connections.
The project will relocate several service lines away from the ocean bluffs, reducing the risk of damage from erosion and improving long-term system reliability. It will also enhance the District’s ability to isolate sections of the water distribution system during maintenance or emergency repairs. In addition, the project will remove an existing water line located in an easement through residential properties that is difficult to access for maintenance.
This area has experienced several water line leaks in recent years, and replacing the aging infrastructure will improve system reliability, reduce future maintenance needs, and enhance operational efficiency.
Commenced January 2026
Pilarcitos Wellfield Replacement Project
The District has six shallow raw water wells under the influence of surface water located in Pilarcitos Canyon that serve as the points of diversion for the District’s surface water rights to Pilarcitos Creek (License for Diversion and Use of Water No. 10598.) Pumping is limited to November 1 through March 31, and the maximum annual diversion volume is 360 acre-feet per year. The District has maximized this water right since the 1960’s, supplying approximately 20% of the District’s current annual water demands.
Three of the wells were built in the 1960’s; two in the 1970’s; and one in the 1990’s. The condition of these aging wells present operational challenges and increasingly high maintenance costs due to scale buildup, fouling, and corrosion that requires frequent and costly cleaning and pump maintenance. In addition, the existing wells lack modern automation and monitoring capabilities and require manual operation.
This Project includes (1) the construction of six new wells “in kind” and associated reinforced concrete pads, piping, valves and appurtenances, and connections to the existing raw water pipeline; (2) destroying five existing production wells; (3) converting one existing production well into a monitoring well; (4) installation of six new submersible pumps; and (5) installation of new electric and controls equipment. Modernizations include adding variable frequency drives (VFDs) at all of the pumps; adding integration with the District’s supervisory control and data acquisition (SCADA) system for remote monitoring and automated control; and adding manual transfer switches for emergency generators.
Completed June 2026
Half Moon Bay Prestressed Concrete Tank and Seismic Upgrades Project
The Half Bay Prestressed Concrete Tank & Seismic Upgrades Project replaced two 1950’s smaller steel tanks located on “Carter Hill” near the Nunes Water Treatment Plant with a new 2.1 million gallon AWWA D110 Type 1 Prestressed Concrete DN Tank – increasing the District’s treated water storage capacity by 1 million gallons. The new tank is 97 feet in diameter and 55 feet tall, including the dome roof. Construction required nearly 1,000 cubic yards of concrete and 21 miles of high-strength prestressing wire.
Why did the District choose concrete over steel? Prestressed concrete tanks are known for their seismic resilience and enhanced water quality protection. They also offer a significant long-term maintenance advantage. Over an 80–100-year service life, a concrete tank requires far less maintenance than a steel tank. In a coastal environment, steel tanks typically require recoating and rehabilitation about every 20 years. The chart below compares the 80-year lifecycle costs of concrete and steel, demonstrating why prestressed concrete was the clear long-term choice for the District.
Completed July of 2025
Highway 92 Pipeline Replacement Project Phase 1
During December 2022/January 2023 winter storms, erosion from the storms exposed segments of the buried pipeline. A temporary bypass 2-inch pipeline adjacent to Highway 92 was installed above ground leaving it at risk to damage and not suitable for long-term use. During a previous storm, another segment of Pipeline was exposed near the Corinda Los Trancos Creek, also putting it at risk for failure. Therefore, this project includes installation of a 12-inch diameter high density polyethylene (“HDPE”) pipe via horizontal directional drilling under Corinda Los Trancos Creek and two crossings of Pilarcitos Creek, with the rest of the pipeline consisting of 10-inch and 6-inch diameter ductile iron pipe installed via open trench. The total length of the new water main is 5,665 linear feet.
Completed July of 2024
Magellan/Highway 1 and Alameda Avenue Pipeline Restoration Projects
Magellan/Highway 1 Portion of the Project
Approximately 475 linear feet of existing 10-inch cast iron pipe was lined with Primus Line, a flexible fabric pipeline liner. This process was performed using the Primus slip lining technique, which avoided causing any disruptions on Highway 1 and the Coastal Trail, and saving the District $2M+ in pipeline replacement costs using traditional methods.
Alameda Avenue Portion of the Project
Around 175 linear feet of the existing 10-inch welded steel pipeline were lined with Primus Line, a flexible fabric pipeline liner.
Completed June of 2024
Nunes Water Treatment Plant Improvement Project
The District has completed upgrades to its Nunes Water Treatment Plant in Half Moon Bay, California. There were numerous improvements made during the 3 years, which included the following main items of work: a new plate settler sedimentation basin, a new caustic soda storage tank, site improvements, filter improvements, clearwell improvements, and electrical/instrumentation improvements. These upgrades provide operational redundancy and efficiency at the treatment plant, so that it has backups in case of equipment failure, allowing for quick restoration of normal operations without significant disruptions to water service.
Staff Report – July 5th, 2024 – Board Meeting (PDF)
Completed June of 2024
Valve Replacement Project
This project involved replacing 15 water main valves in disrepair, removal of a 6″ water main that crossed behind several backyards along 2nd Avenue (between Granelli Avenue and Myrtle Street), and installation and connection of approximately 50 linear feet of new 6″ ductile iron pipe water mains.
Completed February of 2024
Poplar Street Water Main Replacement Project
Prior to the commencement of the City of Half Moon Bay’s Poplar Street Traffic Calming and Safety Project, CCWD replaced 850 feet of existing cast iron main with new ductile iron pipe, domestic services and operating valves adjusted to the new street profile.
