Countywide : New Chemical Will Be Added to Water Monday

A new chemical will be added to the water supply starting Monday after a five-month delay, imposed so that dialysis patients and fish owners could make adjustments to prevent adverse effects.

Chloramine, a combination of chlorine and ammonia, will replace chlorine in water supplied by the Metropolitan Water District, said district spokesman Jay Malinowski. He said the change is needed because the Environmental Protection Agency has determined that chlorine aids the production of trihalomethanes (THMs), which have been found to cause cancer in laboratory animals.

"(Chloramine) isn’t a problem for human consumption but it could be a problem for fish owners and dialysis patients,” Malinowski said. He noted that all hospitals with dialysis units have been informed of the change and those people who undergo dialysis at home must contact their doctors to make the necessary changes in their water supply.

The MWD began adding the chemical in November, 1984, but stopped the process a month later when it was found that some dialysis units hadn’t been correctly adjusted. Several people suffered some reaction, with most exhibiting symptoms of severe lethargy, but there were no lasting effects, said Malinowski.


Because the chemical is toxic to fish, aquarium owners will need to add sodium thiosulfate to their water. The additive is available at pet stores.

All cities in Orange County use MWD water, some augmenting that supply through wells or other water districts. For more information, call the district at (800) 225-5693.