 |
 |
| |
 |
How We Monitor Drinking Water for Safety |
| |
| |
Federal and state regulations require close monitoring of all water supplies. The water the District supplies to customers meets or exceeds all primary and secondary drinking water standards.
Many people work every day to protect the quality of your water. DSRSD employees routinely collect samples from 60 locations throughout the water distribution system. These samples undergo chemical, bacteriological, and physical analysis in the District’s laboratory, which is certified by the California Department of Public Health (CDPH) Environmental Laboratory Accreditation Program. Zone 7 Water Agency, the District’s wholesale water supplier, also continuously monitors water quality.
District employees collect and test samples frequently to monitor drinking water quality.
In all, DSRSD and Zone 7 test for more than 100 substances. DSRSD sends a summary of water quality monitoring to our customers each year in our Annual Water Quality Report, available on our Publications page. A list of substances not detected in our water supply is available here. Zone 7 also publishes an annual Consumer Confidence Report, available at www.zone7water.com. |
| |
|
Frequently Asked Questions about Water Quality |
| |
| |
How often is water tested?
Samples are collected from many places along the distribution pipelines, and a sample from each location is tested at least once a month for coliform bacteria, chlorine residuals, and fluoride. In addition, fluoride is monitored 24/7 online and daily field samples are taken to ensure compliance with CDPH required operating range. Field samples are also cross checked weekly in the District’s lab. Other water quality parameters, including pH, hardness, alkalinity, conductivity, turbidity, and color, are monitored monthly, based on a set of 20 samples defined by the CDPH. The level of total dissolved solids (TDS) is checked weekly. We monitor for other contaminants according to schedules established by CDPH or other regulatory agencies. Zone 7 also performs many quality tests before it delivers the water to DSRSD. |
|
Do you add fluoride?
Yes. Fluoride is a naturally occurring element and a water additive that promotes strong teeth. DSRSD adds fluoride to drinking water to maintain a range 0.7 to 1.3 mg/L, as required by CDPH regulations. Read more. Why is our water hard?
Hardness is caused by naturally occurring minerals such as calcium and magnesium. Our water is a blend of ground and surface water sources. Because the blend varies over the course of a year, customers sometimes notice changes in taste and hardness. Water hardness is determined by the amount of calcium carbonate it contains. In 2010, Zone 7 Water Agency’s imported and local surface water averaged from 89 to 103 milligrams per liter (considered moderately hard), while the groundwater drawn from four wellfields averaged from 234 to 487 mg/L (considered very hard). Zone 7 operates a demineralization plant to slow down the buildup of salts and minerals in our groundwater basin and reduce the hardness of groundwater pumped from the Mocho Wellfield in western Pleasanton. Hard water does not pose a health risk and is not addressed by state and federal drinking water regulations. Read more. Why does my drinking water sometimes smell?
Surface water imported through the Bay-Delta, which usually makes up about three-quarters of our drinking water supply, can occasionally have an earthy or musty taste or smell, caused by algae blooms from warm temperatures and increased sunlight. These taste and odor episodes usually last a few days, from late spring through September, and do not impact the safety of our drinking water.
Odors often have other causes. To track down the cause, let the water run for about 30 seconds. Then rinse and fill a glass. Take the glass of water to a different room and smell the water. |
| |
| |
No smell
Odor is probably coming from bacteria in the P-trap under the drain. Clean the trap (or call a plumber to do so) and repeat the test described above. Other smells could be from home water treatment systems, in which case the system should be checked (e.g., check or replace filters).
Chlorine/Chemical
Odor is usually a result of the chlorine used to disinfect the water supply. If the smell is particularly bothersome, let the water stand in an open container. The chlorine will dissipate. The container can then be covered for later use.
Foul smell
Foul odors often come from drains or garbage disposals. The rotting organic matter or bacteria in the drains/disposals are stirred up when the water is turned on. To get rid of the odor, fill the sink with hot water, add an ounce of household bleach, and allow the water to drain slowly.
|
| |
| |
What do I do if I have problems with my water or other questions?
|
| |
|
Source Water Assessments |
| |
In compliance with the 1996 federal Safe Drinking Water Act, Zone 7 completed source water assessments for all of its wells from 2000-2009. These studies identify potential sources of contamination around wells and establish protective zones. Groundwater is vulnerable to releases from chemical and petroleum pipelines, tanks (i.e., at gas stations or dry cleaners), machine shops, photo processing and printing facilities, septic tanks, and wastewater collection systems. However, organic contaminants from these sources have never been found in Zone 7 wells. Most of our water is imported from the State Water Project (SWP) through the South Bay Aqueduct. Every five years, the SWP conducts a “sanitary survey,” which is an onsite review to assess the SWP's ability to produce and distribute safe drinking water. The most recent study was in June 2007 and a similar study of the South Bay Aqueduct (SBA) watershed was completed in 2008. Most of the contaminants detected by these studies originate in the Sacramento and San Joaquin watershed and the Delta from agricultural drainage, wastewater treatment plant discharges, urban runoff, recreational activities, and seawater intrusion. After leaving the Delta, the quality of SBA water may also be vulnerable to pollution from local cattle grazing, wildlife, and recreational activities in the watersheds of Bethany and Del Valle reservoirs.
To request copies of the studies or for more information, contact Zone 7 Water Quality Manager,
Gurpal Deol at (925) 447-0533.
Revised on |
|
|
