The Santa Clara Valley Water District operates three water treatment plants that clean and disinfect imported water and/or water captured in four of our local reservoirs.
Rinconada Water Treatment Plant
The Rinconada Water Treatment Plant is the second-largest of Valley Water's plants. Completed in 1967 by the Santa Clara County Flood Control and Water Conservation District - the precursor to today's water district - the plant can treat and deliver up to 80 million gallons of water each day for retailers who supply residential and commercial users in the West Valley, including the cities of Santa Clara, Campbell, Sunnyvale, Cupertino, Mountain View, Monte Sereno, Saratoga and Los Altos and the towns of Los Gatos and Los Altos Hills.
Water source
Rinconada mainly draws water from the South Bay Aqueduct (SBA) and the San Luis Reservoir. The San Luis Reservoir is a key component of the federal Central Valley Project. Water from the Sacramento-San Joaquin Delta pumps into the Delta-Mendota Canal and then into the San Luis Reservoir. The SBA is a key component of the State Water Project system. Valley Water is one of many users that draw water from this reservoir. Valley Water's local Anderson and Calero reservoirs can also supply the plant.
Contact information
If you have any questions or concerns about the Rinconada Water Treatment Plant, please contact Neighborhood Liaison Tony Mercado at (408) 630-2342 or by e-mail at [email protected].
If an urgent problem arises after regular business hours, please call the on-duty plant supervisor at (408) 630-2121.
Valley Water is committed to providing a healthy, clean, reliable and affordable water supply that meets or exceeds all applicable water quality regulatory standards in a cost-effective manner.
Penitencia Water Treatment Plant
About the Penitencia Water Treatment Plant
The 17-acre Penitencia facility opened in 1974 as the second of Valley Water’s water treatment plants. Penitencia Water Treatment Plant treats and delivers up to 40 million gallons of water each day for the cities of San José and Milpitas and local water providers. One of the local water providers such as the San José Water Company.
Penitencia is the latest plant to integrate the use of ozone gas in its water treatment process to improve water quality.
Management and operations
The Penitencia Water Treatment Plant has a team of experienced professionals that includes certified operators, mechanics, industrial electricians, instrumentation and control technicians, plant maintenance supervisor, and water treatment operations supervisor.
The treatment plant operators manage the untreated water flowing into the plant and the treated water going out of the plant. They monitor and adjust treatment processes based on changing raw water quality and ensure that the drinking water treated at the plant meets and exceeds local, state, and federal standards. The state of California certified each of our operators, who must meet experience guidelines and pass an examination for each of the five levels of certification. Our operations supervisor maintains the highest level of certification. Valley Water invests in their training to ensure they can operate and manage our systems at the highest levels possible.
Together, this team ensures the safety of the plant and the quality of drinking water delivered to the community. They work hard to operate the facility efficiently and to treat waters of different characteristics to high-quality standards. Penitencia’s water sources Santa Clara County relies on water imported from the Sierra Nevada watersheds, transported through aqueducts, canals and pipes, for a majority of its water supply. Penitencia receives the bulk of its water via the Sacramento-San Joaquin Delta and then the South Bay Aqueduct, which
enters our county at its northern border. The facility can also receive imported water via the San Luis Reservoir, just south of our county line, which may be stored at Anderson Reservoir or another of our local reservoirs. These various sources provide operational flexibility, allowing the facility to keep receiving water supplies, even if a portion of the system is offline for maintenance. Having several water sources helps improve water reliability, gives us flexibility in operating our treatment plants, and ensures our ability to continue serving our community.
How is Your Water Treated?
Removing solids
At Penitencia, we remove the solid particles that settle to the bottom of three large tanks called sedimentation basins, the largest feature of the plant. Each basin is about 18 feet deep and holds 800,000 gallons of water. First, we add special chemicals called coagulants to the water that enters the basins. In this “Coagulation/Flocculation” phase, these chemicals allow the finer particles to clump together to form larger, heavier, settleable solids. Next, in the “Sedimentation” phase, we allow these settleable solids to sink to the bottom. Rakes slowly rotate along the bottom of the basins scraping the settled sludge towards the end of the basins where it is removed for further treatment. The water at the top of the tanks, with less solids, overflows to troughs located across the top of the basins. Next, this water is ozonated to disinfect and remove taste and odor from the water just before filtration.
Filtration Process
The Penitencia Plant can have up to six filters in service to remove particles that are small enough to be suspended in water. Each is capable of filtering 7 million gallons per day through a layer of sand and coal that is specialized for water filtration. Each filter takes up an area of 780 square feet. The filters are backwashed periodically to remove all the entrapped particles.
Final disinfection
Chlorine and ammonia is used for final disinfection. Chlorine is added right after filtration, and then ammonia is added just before the water leaves the plant to form chloramines, a long-lasting disinfectant for the distribution system. After treatment, water flows through the pipelines all across Santa Clara Valley. Your local water provider takes it from here and distributes the water to homes and businesses.
Testing ensures quality
Valley Water has strict quality control measures and follows all state and federal regulatory requirements. To ensure we deliver the highest quality water, in addition to the water treatment process, our water quality lab conducts a wide range of tests for constituents under strict quality control and regulatory requirements.
More Information
Download a copy of the Fact Sheet here.
For more information, visit valleywater.org/accordion/penitencia-water-treatment-plant or contact Public Information Representative Jose Villarreal at (408) 630-2879 or by email at [email protected].
Santa Teresa Water Treatment Plant
The Santa Teresa Water Treatment Plant is one of three water treatment plants in the Santa Clara Valley Water District’s system. It produces safe drinking water for most of South San Jose - Almaden Valley, Blossom Valley and Santa Teresa - supplying water to residential and commercial users. The plant can also serve the majority of the Penitencia Water Treatment Plant’s service area when needed.
As the largest of Valley Water’s three treatment plants, Santa Teresa can treat and deliver up to 100 million gallons of water per day. Most of the water coming into this plant is imported from San Luis Reservoir, a key component of the federal Central Valley Project. Water from the Sacramento-San Joaquin Delta is pumped into the Delta-Mendota Canal and then into the San Luis Reservoir. Valley Water is one of many users that draw water from this reservoir. The Santa Teresa Water Treatment Plant is also fed from Valley Water’s local supplies at Anderson and Calero reservoirs.
The Santa Teresa Water Treatment Plant opened in 1989, integrating the use of ozone into its water treatment process in 2006 to improve its drinking water quality. Ozone is an excellent addition to the drinking water treatment process because it is a very strong disinfectant yet creates less disinfection byproducts than chlorine. Disinfection byproducts at high levels can be a health concern.
Contact information
If you have any questions or concerns about the Santa Teresa Water Treatment Plant, please contact Neighborhood Liaison Tony Mercado at (408) 630-2342 or by e-mail at [email protected].
Valley Water is committed to providing a healthy, clean, reliable and affordable water supply that meets or exceeds all applicable water quality regulatory standards in a cost-effective manner.