January 27, 2010 > Interview with Kathleen Phalen
Interview with Kathleen Phalen
Kathleen Phalen, Utility Engineer for the City of Milpitas, explained how the City monitors and reports the quality of its drinking water. The Public Works Department's Utility Section also prepares the annual Consumer Confidence Report (CCR).
The 2009 CCR was issued to the public in June 2009 and is based on data from calendar year 2008. It provides qualitative descriptions of Milpitas' wholesale water sources and summaries of water analyses. As per California Department of Public Health (CDPH) regulations, the next CCR is due in late spring 2010 and will contain 2009 data.
Phalen expects information for this year's report will be very similar to the data reported in the 2009 report.
TCVM: Does Milpitas prepare the CCR using information from water wholesale sources?
Phalen: Yes, the San Francisco Public Utilities Commission (SFPUC) and Santa Clara Valley Water District (SCVWD) provide information. We also use our own analytical data collected weekly from sampling points throughout the distribution system.
TCVM: How is the CCR circulated?
Phalen: We mail a copy to every water customer in Milpitas and make additional copies available via the City's website and at various City facilities such as City Hall. Each year, we receive about 100 telephone calls from the public responding to the report.
TCVM: Why does Milpitas obtain most of its water from SFPUC?
Phalen: Prior to 1993, Milpitas was served only by SFPUC but the City's contract with SFPUC limits its purchases to 9.23 million gallons per day, averaged over a year. The City entered into a second contract with SCVWD to diversify its portfolio and expand supply. Today, roughly one-third of the City's supply is treated surface water from SCVWD, imported from the Sacramento/San Joaquin Delta.
TCVM: In an emergency, how would Milpitas ensure uninterrupted supply?
PHALEN: Via an intertie which is a connection between two water distribution systems. Valves at the connection are typically kept closed but can be opened in an emergency. Water flows from the system with higher pressure to the one with lower pressure. Milpitas has emergency interties with Alameda County Water District and San Jose Water Company that haven't been used. We can either share or receive water from them should one of our agencies have a supply problem such as a large water-main break. Interties between neighboring agencies increase system reliability.
TCVM: How does water reach customers from the wholesaler?
Phalen: Water flows from the wholesalers' transmission systems through turnouts (metered and valve lateral connections) into the City's distribution system. The City has four turnouts located along the Hetch Hetchy Bay Division Pipelines 3 & 4 that run through the City and one at the terminus of the SCVWD Pipeline. The City's distribution system includes over 200 miles of water main pipe, pressure-regulating valves, storage reservoirs and pumps. Water mains are typically installed beneath public streets though some are in public easements. Homes and businesses tap into the public water system through pipes connected to a meter typically set at the street curb and thence to the water main in the street or easement.
TCVM: Does water dissolve and absorb contaminants from the transmission mechanism?
Phalen: Water can dissolve contaminants and carry suspended solids eroded from storage and transmission pipelines. Water systems can also harbor bacterial contamination. Water treatment processes are designed to minimize the occurrence of such contamination. The wholesaler's and City's water quality-testing programs are designed to detect such contamination. If it should occur and exceeds regulatory limits, the City would notify customers, halt distribution and correct the problem.
TCVM: Who sets the monitoring and reporting requirements with which SFPUC complies?
Phalen: SFPUC is both retailer and wholesaler. As a retailer to City of San Francisco customers, it must follow the same regulations as all large-system distributors in California. These regulations are established and enforced by the CDPH - Drinking Water Program.
TCVM: How would you respond to people who think tap water is unfit for human consumption and fish?
Phalen: The City's annual CCR documents the City's water quality, as sampled and analyzed in accordance with state law.
TCVM: Who considers what is safe to add to water?
Phalen: CDPH regulates all aspects of public drinking water including acceptable use of disinfectants to prevent water-borne disease, monitoring and reporting requirements and the content of the CCR. SFPUC began fluoridating in November 2005. California law (AB 733, Jackie Speier, 1995) requires fluoride be added to water, if funding is available to construct the treatment processes. The reason is fluoride improves dental health by reducing incidence of tooth decay (visit the Centers for Disease Control and Prevention website for more information).
TCVM: What are water constituents?
Phalen: We use this term in the CCR. Constituents are generally either chemicals or microbes found in water. Some constituent measurements, such as hardness, pH (acidity/alkalinity) and specific conductance, would correctly be called properties because they describe how water behaves but the properties are caused by chemicals in the water.
TCVM: Should I boil my tap water?
Phalen: Boiling tap water and water from other sources can kill microbial contaminants but this is generally unnecessary and not recommended. Public water systems have already treated and tested tap water for microbial contamination. In an emergency, public water agencies are required to issue "boil water" notices if there is risk of contamination. By the same token, freezing has minimal impact on water quality and will not disinfect it.
TCVM: Why does storm water drain to the Bay?
Phalen: In the past century, most municipal storm drain systems were installed to remove rainwater from public streets. Typically, storm water is carried to the nearest natural water body, such as a creek. For Milpitas, it's San Francisco Bay. Many people don't realize the storm drain system is separate from the sanitary sewer system which is routed to a treatment plant. The "No Dumping - Flows to Bay" message informs people that dropping refuse and pollutants in street gutters or catch basins is the same as placing them in a creek or the Bay.
Storm water picks up deposited oil and other contaminants before flowing into a drain. The state recently adopted a Bay Area Municipal Regional Stormwater Permit (MRP) requiring new construction of streets and other surfaces, such as roofs, driveways, sidewalks, etc., to drain run-off through a treatment system before discharge to a storm drain. However, this only applies to new construction or reconstruction so will not include all existing streets and roads for many years.
TCVM: Has Pinewood Well been used?
Phalen: The City maintains Pinewood Well in a fully functional state in case of emergency but hasn't introduced water from it into the public system for many years. The well draws water from a natural aquifer about 500 ft below ground. The water has a naturally high mineral content so is "harder" than SFPUC or SCVWD surface waters. Pinewood Well is regularly monitored, as required by CDPH, to maintain its active status.
For more information, visit City of Milpitas (www.ci.milpitas.ca.gov), Santa Clara Valley Water District (www.valleywater.org), San Francisco Public Utilities Commission (www.sfwater.org), State Water Resources Control Board (www.waterboards.ca.gov), California Department of Public Health (www.cdph.ca.gov) and Centers for Disease Control and Prevention (www.cdc.gov).