M5.4 Consumer Confidence Reports & Water Quality

M5.4 Consumer Confidence Reports & Water Quality

Daly City Consumer Confidence Report on Water Quality: https://ofmpub.epa.gov/apex/safewater/f?p=136:103:::NO:::

What is the source of your drinking water? Where does your water ORIGINATE? 

I reside in a town adjacent to San Francisco called Daly City. Daly City’s municipal drinking water wells comprise what is termed "groundwater." About half the water distributed by the Daly City Water System is from local wells that is blended with San Francisco Water. Drinking water is drawn from an average depth of 300 feet below ground from a large aquifer known as the Westside Basin that serves a large portion of the northern San Mateo Peninsula and extends north to Golden Gate Park in San Francisco. 

What chemicals were found in your water that were higher than expected?

Because of its protected environment and the consistency of City monitoring results, the well water is only required to have Chloramine, a drinking water disinfectant (combination of five parts chlorine and one part ammonia). It is a more stable disinfectant than chlorine, lasts longer in water, and produces lower levels of disinfection byproducts called trihalomethanes and halacetic acids, which are suspected carcinogens. Although there were chemicals found in my city's drinking water, none were reported to be higher than regulation levels. The following were reported:

Arsenic: New regulations for reporting arsenic levels have been established at less than 10 parts per billion. Staff has completed preliminary testing of its groundwater at five local wells. Current testing standards detect arsenic at 1 part per billion, and Junipero Serra Well test results were 1.4 parts per billion, while all other wells tested were non-detect. While results are below the standard, Daly City will provide an informational statement if for any reason sampling exceeds 5 parts per billion as this testing program continues.

Chromium-6: Chromium is currently regulated under the 50 parts per billion maximum contaminant level for total chromium. There is no minimum contaminant level established at this time for Chromium-6; however, testing from three Daly City wells were as follows:

Well#4 - 19 parts per billion; Jefferson Well - 9.7 parts per billion and Vale Well - 16 parts per billion

What chemicals did you NOT expect to find in your water?

I did not expect to learn that our drinking water contains byproducts called trihalomethanes and halacetic acids, which are suspected carcinogens. While the current standard is a maximum trihalomethane level of 80 parts per billion, Daly City water currently tests at 30.2 parts per billion. Halacetic acids currently test at 17 parts per billion, well below the standard of 60 parts per billion.             Are there associated health risks with the chemicals found in your water?

Although arsenic, chromium 6 and disinfection byproducts called trihalomethanes and halacetic acids (suspected carcinogens) were documented to be below hazardous levels in Daly City drinking water, lead and copper are also included. Excessive amounts of lead 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. In 1993 the United States Environmental Protection Agency mandated that lead and copper monitoring be conducted by all water systems. Daly City completed the required monitoring and corrosion study in 1994. In December 2001, lead and copper samples were again collected and results remained under any notification levels.  Where does your water come from? The source! Track it from the source to your tap. The Daly City water system is supplied by two sources, the San Francisco Water Department and local Daly City wells. San Francisco Water Department is supplied exclusively by their surface water system which is mostly reliant on the Hetch Hetchy Watershed, and to a lesser degree local reservoirs. The Hetch Hetchy watershed provides approximately 80 percent of the San Francisco Public Utilities Commission (SFPUC) supply. The Hetch Hetchy system captures water inflows from the watershed in the Hetch Hetchy Reservoir. This reservoir, the primary source for the system, is filled by spring snowmelt, runoff and the Tuolumne River. Water in the Hetch Hetchy Reservoir is treated but not filtered because it is of such high quality. 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.  What did you discover about your water quality? Despite the chemicals in the Daly City drinking water, I still consume Daly City tap water without any hesitations. I haven't gotten sick yet. I have confidence in the safety of our water system and the water system operators.  Do you use a filter for your water? I do not filter my water, because I trust that my tap water is clean and safe. What are you trying to filter out? I believe that people who filter than water are attempting to rid it of particles and microbials. Do you drink bottled water?   How does this square with what you learned when you watched the Story of Bottled Water? I drink tap water and bottled water that is given to me. My parents strictly drink bottled water, because they came from a third world country where they did not trust the government or public plumbing systems. Although I showed them the video "Story of Bottled Water," they still do not believe that tap water is as safe or even as bottled water.