The Alameda and Peninsula watersheds provide the remaining 20 percent of the SFPUC water system. The Alameda watershed is located in the East Bay, and represents about 10 percent of the total water supply, with water captured and stored in two reservoirs: Calaveras and San Antonio. The Peninsula watershed, representing the remaining ten percent of the SFPUC supply, captures runoff in four reservoirs, Crystal Springs, San Andreas and the smaller Pilarcitos and Stone Dam reservoirs.

The six reservoirs in the Alameda and Peninsula watersheds capture rain, local runoff and some also store Hetch Hetchy water for use by the SFPUC.

Water from the Hetch Hetchy Reservoir that is stored locally is treated and filtered, as is any local water source. The SFPUC's water has been fluoridated for nearly fifty years.

Lead and Copper
Lead in amounts in excess of established action levels in drinking water can cause delayed physical and/or mental development in infants and attention span and learning deficits in children. In adults it can cause kidney problems and possible high blood pressure.

Because of these concerns the EPA mandated in 1993 that lead and copper monitoring be conducted by all water systems. Daly City completed the required monitoring and corrosion study in 1994. The results of the study were well under any action levels and met all quality standards.

In 1998, under advisement from the EPA, DHS required local water systems to complete their studies. A joint effort was organized by the SFPUC for collection and analysis by the member agencies.

Since Daly City had previously conducted the study, an agreement was reached with DHS to do a special water quality study to determine the aggressiveness (corrosivity) of our well water and determine ways to meet the requirements for corrosion control in our water system. The study was performed in September 1999, and the results of the second Daly City study showed results were again under any action levels and met all quality standards.

In December 2001, lead and copper samples were collected and this third Daly City study showed results remained under any action levels. The results of the second and third Daly City studies indicate that the well water blend with Hetch Hetchy supply provided a buffering effect, which lowered the corrosivity of the water.

Inorganic Contaminants such as salts and minerals which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming.

Organic Chemical Contaminants including synthetic and volatile organics which are by-products of industrial processes and petroleum production and can also come from septic systems, urban stormwater runoff, agricultural chemicals such as chemical fertilizers and gas stations.

MTBE, a gasoline additive, has become a recent water quality concern. This organic contaminant has rapidly been made a primary contaminant by DHS and is regularly monitored. All test results for MTBE in the City's wells and distribution system have been rated "non-detect".

Radioactive Contaminants which can be naturally occurring, or the result of oil and gas production and mining activities.

Pesticides and Herbicides may come from a variety of sources such as agriculture, urban stormwater runoff and residential uses.

Unregulated Contaminant Monitoring helps the U.S. EPA and the State Department of Health Services (DHS) to determine where certain contaminants occur and whether the contaminants need to be regulated. During 2000, the SFPUC monitored for twelve unregulated contaminants including MTBE, perchlorate, herbicides, and pesticides. These contaminants were not detected in any of Daly City's or SFPUC’s supplies

Giardia, a parasitic microbe found in most surface water supplies, can pose a potential health threat. If swallowed, it can produce the same symptoms as does Cryptosporidium. The SFPUC tests for Giardia in both source and treated water at least quarterly. The SFPUC occasionally (about 23 percent of the time) detects low levels of Giardia in the Hetch Hetchy, East Bay, and San Francisco Peninsula source (untreated) waters at an overall average level of 12 Giardia/100 liters of water.

Drinking water, including bottled water, may reasonably be expected to contain at least minute amounts of some contaminants including Cryptosporidium and Giardia. The presence of small amounts of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the Environmental Protection Agency’s Safe Drinking Water Hotline at (800) 426-4791.

Please note that Cryptosporidium and Giardia are associated with surface water supplies and are not commonly detected in groundwater. Daly City's wells in previous years have never had a detected level of either of these microbes.

Maximum Contaminant Level Goal (MCLG): The level of a contaminant in drinking water for which there is no known or expected health risk. MCLG's are set by the U.S. Environmental Protection Agency (U.S. EPA).

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. Primary MCL's are set as close to the PHG's and MCLG's as is economically and technically feasible. Secondary MCL's are set to protect odor, taste and appearance of drinking water.

Primary Drinking Water Standard: MCL's for contaminants that affect health along with their monitoring and reporting requirements and water treatment requirements.

Variances and Exemptions: State or EPA permission not to meet an MCL or a treatment technique under certain conditions. Daly City and the SFPUC have no variance or exemption for MCL’s.

Treatment Technique: A required process intended to reduce the level of a contaminant in drinking water.

Regulatory Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

Waiver: Permission from the State Department of Health Services (DHS) to decrease the frequency for a particular contaminant. This decision is based on previous monitoring indicating a firm belief that the contaminant does not exist in the system. Waivers are for defined periods of time and require an application for extension.

SFPUC has fluoridated their treated water for almost 50 years. Depending on your location in Daly City, you may receive only SFPUC supplied water and have the optimum level of fluoride content which is only 1 mg/L (parts per million). In other areas receiving blended well and SFPUC water, since we do not fluoridate our well water, you may be receiving water with fluoride levels as low as 0.3 mg/L. By year end 2003, Daly City is anticipating adding systems to fluoridate the well water blended at the City's three pump stations to meet the optimum standard throughout the entire community.

Chloramination

One of the current goals of the EPA and DHS is to lower disinfection byproducts in drinking water. On October 20, 2003, the San Francisco Public Utilities Commission (SFPUC) has scheduled the switch from chlorine to chloramine (5:1 ratio chlorine to ammonia) as a disinfectant for drinking water. At that time, Daly City will make the same modification to the local system to maintain a uniform disinfection process as SFPUC purchased water is blended with local groundwater. Most Bay Area utilities and many communities nationwide have already switched to chloramine for drinking water disinfection.

There are many reasons for the switch to chloramine. Namely, chloramine is more stable than chlorine and lasts longer in the distribution system, thereby improving public health protection. Chloramine also produces lower levels of disinfectant byproducts like trihalomethanes (TTHMs), suspected carcinogens that form when chlorine mixes with natural organic substances in water. The conversion will enable Daly City to maintain compliance with stringent present and anticipated regulatory standards. Recent changes to regulatory standards lowered allowable TTHMs from 100 parts per billion (ppb) to 80 ppb. Daly City’s current average TTHM level is 65.8 ppb, and this average should only decrease with the conversion to chloramine.

Chloraminated water is safe for consumption and for all general purposes. However, as with chlorine, precautions must be taken to remove or neutralize chloramine during certain uses such as the kidney dialysis process, the preparation of water for fish tanks and aquariums, and for businesses requiring highly processed water. Unlike chlorine, chloramine cannot be removed from water by boiling it, adding salt to it, or by letting an open container of water stand to dissipate chlorine gas. It can only be neutralized or removed with specific treatment methods. DHS, the SFPUC and the Trans Pacific Renal Network will notify hospitals, clinics and home users of required treatment methods. All dialysis units must be inspected and certified by DHS for removal of chloramine. Aquarium and fish tank owners can utilize inexpensive water treatment products (drops or tablets) or specified carbon filters that are readily available at most pet stores and aquarium dealers.

Public notices will be sent out this summer to businesses and water customers prior to the October 2003 conversion. Additional information may be obtained by visiting the SFPUC’s website at better.sfwater.org or by contacting the Department of Water and Wastewater Resources at (650) 991-8200.

Conjunctive Use Aquifer Recharge Study

As part of ongoing efforts to preserve the Westside Basin Groundwater Aquifer for drinking water purposes, Daly City amended its Water Supply Contract with the San Francisco Public Utilities Commission to conduct an aquifer recharge study. The purpose of the study is to jointly assess available groundwater storage capacity within the Westside Basin.

Conjunctive Use refers to balancing the use of available surface water supplies with that of groundwater. During certain years, when supplemental surface water is available, Daly City agrees to buy that supplemental water at a discount price in lieu of extracting groundwater from its local wells. The purpose of the study is to assess the impact within the groundwater basin on aquifer storage and whether the basin can be used to enhance aquifer recharge. It is hoped that improved basin recharge and storage will provide additional water to the region that can be utilized during drought conditions. Local impacts, if any, once the program is implemented may involve some residents noticing a slightly different taste in their water from the higher amount of surface water blend from the reduction of groundwater. It is expected that this impact will be minimal.