But that combination is present in public water systems throughout the United States. Here in Sunnyvale, it's in almost 44 percent of the water that comes out of showerheads, hoses and faucets.

Residents in Sunnyvale are just a fraction of the 2.4 million people served by the San Francisco Public Utilities Commission. In February 2004, the SFPUC switched its disinfectant systems from chlorine to chloramine. According to Maureen Barry, coordinator for community involvement for the SFPUC, the commission made the switch because chloramine stays in the water supply longer, providing a more long-term disinfectant.

But soon after the change in chemicals, mysterious asthma-like attacks and respiratory problems arose in some people living on the peninsula.

A group of residents suffering the attacks formed the Concerned Citizens Against Chloramine on June 20, 2004, to spread information and lobby for change.

On Aug. 22, the group finally met with the SFPUC, at the Taraval police station in San Francisco. The standing-room only crowd listened to presentations from Denise Johnson-Kula, leader of the Concerned Citizens group and Barry, and took part in a lengthy question-and-answer session.

Barry said the commission's own research suggested chloramine was the best option to meet its goal, which is to provide clean water to its service areas.

"We're pleased with our test results and very pleased with what has happened since we went over to chloramine," Barry said. She added that health concerns should be taken to local health departments or personal physicians.

Johnson-Kula and other members of her group said many of those studies are concerned with water quality and cleanliness, not the affects on humans.

The one study done in response to citizen complaints was a phone survey of 17 people between September 2004 and January of this year by the San Francisco Department of Public Health. Respondents were asked about skin problems.

Although 15 of those surveyed talked about itchiness and other problems, the study concluded that there was not a consistent pattern.

"As new information about SFPUC customer complaints becomes available in the future, a formal study may be necessary," the conclusion said.

"Instead of using the public as a giant guinea pig to study the effects, they should have been doing tests before putting this into our water supply," Johnson-Kula said.

At the meeting, Johnson-Kula said her group had documented more than 100 complaints from Bay Area residents.

While there was no testing, Brown said the SFPUC used evidence from studies across the United States in deciding to use chloramine. She referred to Denver Water, the company that serves the mile-high Colorado city, where chloramine has been used for more than 70 years, with few major complaints.

According to a 2004 water quality study, Denver averages 1.5 milligrams of chloramine per liter of water, while the SFPUC averages 2.5 to 2.7 grams.

"That is a huge magnitude of difference, and could be what is causing the problems," Johnson-Kula said.

According to the Santa Clara Water District--which does not get its water from Hetch-Hetchy--the average amount of chloramine for most of the South Bay not served by SFPUC is between 2 and 2.5 milligrams, only slightly lower than SFPUC's numbers.

Johnson-Kula and many of the CCAC members said the only safe water for them is well water, such as the kind popular in South San Jose. She washes her clothes on her parents' property in Gilroy.

Bruce Dronek--who works out in a Sunnyvale gym after work during the week said, "I don't shower after working out anymore, so I just sweat and stink all the way home," Dronek said.

But after the meeting, Dronek said, "I think we're coaxing them into helping," Dronek said. "I think it will happen, but slowly."

The next public meeting of the CCAC will be at the Menlo Park Library, 800 Alma St, Menlo Park, Sept. 6 at 7:30. For more information on Concerned Citizens Against Chloramine, visit www.chloramine.org.