Water Disinfection

Using chloramines to disinfect drinking water is a common standard among utilities in the United States and around the world. CCWD has been using chloramines since the early 1980s.

Most major utilities in California use chloramines as their drinking water disinfectant. In the Bay Area, Santa Clara Valley Water District, Alameda County Water District (since 1983 on their surface water supply), Marin Municipal Water District, Zone 7 Water Agency in Livermore, Pleasanton and Dublin (since 1990) and the East Bay Municipal Utility District (since 1998) provide chloraminated water to their customers. The Metropolitan Water District of Southern California has provided chloraminated water since the mid 1980s.


Chlorine has been safely used for more than 100 years for disinfection of drinking water to protect public health from diseases which are caused by bacteria, viruses and other organisms.

Chloramines, the monochloramine form in particular, have also been used as a disinfectant in drinking water since the 1930s.

Chloramines are produced by combining chlorine and ammonia. While obviously toxic at high levels, neither pose health concerns to humans at the levels used for drinking water disinfection.

Chloramines are a weaker disinfectant than chlorine, but more stable, thus extending disinfectant benefits throughout a water utility’s distribution system. They are used as the primary disinfectant for your water. Chloramines are used for maintaining a disinfectant residual in the distribution system so that disinfected drinking water is kept safe.


Chloramines, like chlorine, are toxic to fish and amphibians at levels used for drinking water.

Unlike chlorine, chloramines do not rapidly dissipate. Neither do they dissipate by boiling. Fish owners must neutralize or remove chloramines from water used in aquariums or ponds. Treatment products are readily available at aquarium supply stores. Chloramines also react with certain types of rubber hoses and gaskets, such as those on washing machines and hot water heaters. Black or greasy particles may appear as these materials degrade. Replacement materials are commonly available at hardware and plumber supply stores.

A Special Note to Kidney Dialysis Patients

Chloramines or chlorine needs to be removed from water that is used in kidney dialysis machines. Medical centers that perform dialysis are responsible for purifying the water that enters the dialysis machines. If you are a dialysis patient receiving dialysis in your home, please contact your dialysis facility or your physician. Kidney dialysis patients can drink, cook and bathe in chloraminated water. Only the water used in dialysis machines needs to have chloramines removed.

For more information, call our Water Quality Hotline at 925-688-8156 or send us an email.