In Fall 2003, the San Francisco Public Utilities Commission (SFPUC) will switch from chlorine to chloramine disinfection for drinking water in San Mateo, Santa Clara and Alameda counties. Chloramine, a combination of chlorine and ammonia, is considered a better disinfectant than chlorine alone. Chloramines have been used safely in the U.S. and Canada for many years and many Bay Area communities are successfully using chloramine disinfection.

Chloramine is regarded as a better disinfectant than chlorine alone because it lasts longer in water to more effectively remove pathogens such as bacteria and viruses. Compared to chlorine, chloramine produces lower levels of trihalomethanes, suspected carcinogens that form when chlorine mixes with natural organic substances in water.

The SFPUC recommends reviewing your current chlorine removal systems to assess any needed changes to remove chloramine for the Fall 2003 conversion. A two milligram per liter chloramine level with a chlorine to ammonia-nitrogen ratio of five to one is expected. A residual disinfectant range of two to four milligrams per liter is forecast. Changes in pH, temperature or turbidity are not anticipated.

Companies report adding additional activated carbon canisters to their filtration systems or increasing chemical dosage to remove chloramine. Monitoring your system before and after conversion will ensure that the treated water meets your requirements.

Note that chloramine cannot be removed by boiling water, adding salt or letting water stand in an open container.

Chloramine can cause rubber parts in plumbing systems to deteriorate. The SFPUC refers to this issue on its Web site by stating, "After the conversion, rubber parts on some household plumbing and water heaters may degrade faster than previously experienced. When replacing rubber plumbing parts, ask for chloramine-resistant parts, which are readily available. Plumbing and hardware supply stores and plumbers will be able to provide further information."

Chloraminated water can harm fish and amphibians, such as turtles and frogs. To protect fish and amphibians, remove chloramine from water by using inexpensive water treatment products (available as drops or tablets) or specified carbon filters. These products are readily available at most pet supply stores and aquarium dealers.

Web resources for fish and amphibian-related information:
• http://www.sfaquarium.org
• http://www.sfbakc.org
• http://www.aquariacentral.com

Like chlorine, chloramine can harm kidney dialysis patients during the dialysis process if the chloramine is not removed from water before entering the bloodstream. It is safe for dialysis patients to drink chloraminated water because the digestive process neutralizes chloramine before it enters the bloodstream. For further information, contact your dialysis provider or the Trans Pacific Renal Network at (415) 472-8590 or http://www.network17.org.

The SFPUC can answer your questions about the chloramine disinfection change.