Water Quality

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Zone 7 Reports Algae Bloom Is Affecting Water Taste and Odor

April 27, 2017 -- It's spring and Zone 7 Water Agency is seeing its first glimpse of water-borne algae in the water delivered to its local treatment plants. The current algal bloom is temporary and should clear up naturally within a week or two. Their water treatment process ensures the water is safe to drink and meets all state and federal standards.

When water-borne algae are present in source water, Zone 7 adds powdered activated carbon to reduce the dirty, musty taste and odors, but this treatment is not 100 percent effective. To address this, Zone 7 is upgrading its plants by adding ozone treatment over the next few years. Ozone is significantly more effective than other treatment technologies at treating algal byproducts that cause the unpleasant taste and odor.

Scroll down to Water Quality FAQs for more information. 

How We Monitor Drinking Water for Safety

  To closely monitor water safety, DSRSD employees collect representative samples for field testing as well as analysis in the district’s laboratory.

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 our water. DSRSD employees collect representative samples from 60 locations throughout the water distribution system. The district’s laboratory, which is certified by the State Water Board Division of Drinking Water’s Environmental Laboratory Accreditation Program, analyzes the samples. Zone 7 also monitors water quality continuously online, as well as with instantaneous, or “grab,” sampling. In all, DSRSD and Zone 7 test for more than 100 water quality standards, including coliform bacteria, minerals, metals, fluoride, residual amounts of chlorine used as a disinfectant, and many other chemicals.

DSRSD publishes a water quality report by June 30th each year that summarizes water quality monitoring results from the previous calendar year. We notify all customers when the report is available in our online library. To request a printed copy, call Customer Service at (925) 828-8524. Zone 7 also publishes an annual Consumer Confidence Report.

Total Coliform Notices

In the fall of 2016, samples from two areas of the DSRSD water system exceeded the drinking water standard (maximum contaminant level) for total coliform bacteria. The water was safe to drink at all times. This was not an emergency. Please visit Coliform Notices for more information.

Water Quality FAQs

Expand/Contract Questions and Answers

  • What do I do if I have problems with my water or other questions?

  • Why does the taste of our tap water sometimes change?

  • Why does our water taste different than EBMUD's?

  • What is being done to improve water taste and address blue-green algae?

  • Does our water meet safety standards for chromium 6?

  • How hard is our water?

  • What is being done to improve water hardness?

  • What do you advise about water softeners?

  • Does our tap water contain fluoride?

  • Is our water tested for lead?

  • How often is water tested?

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