The Green Gate
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Drinking Water Quality
Drinking Water Generally Safe, but San Francisco Sometimes Has High Levels of TTHMs
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Clean, safe drinking water is crucial to good health. For the most part, the Bay Area's drinking water is within legal limits for contaminants, but the exceptions can be serious, especially for people who are most susceptible. In addition, evidence increasingly shows that some of the limits are too lax in the first place. The problem is compounded by water utilities' failure to clearly convey information about safety risks in their reports to customers.

To evaluate drinking water quality in the Bay Area, NRDC researchers looked at consumer confidence reports (also known as right-to-know reports) provided by six water agencies in the Bay Area's nine counties for the years 1999 and 2000.

Researchers focused on several dangerous contaminants, including arsenic, chromium, Cryptosporidium (a parasitic microbe), MtBE (a gasoline additive), and total trihalomethanes (TTHMs, a byproduct of chlorination), comparing the levels of these contaminants in Bay Area water with legal limits set by the federal government.

The Bay Area's average water quality was within these legal limits, but TTHMs spiked above the limit in San Francisco. San Francisco also reported that Cryptosporidium was occasionally found at very low levels in its treated water in 2000, which could be serious for people with compromised immune systems. Alameda was the only water district that reported any detections of MtBE, and only in very small amounts. Contra Costa Water District reported that testing of source water showed very low chromium levels. No district reported any detections of arsenic.

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