Suez has sent a notice to its Rockland County customers about high levels of chlorine byproducts in their water.

"We want to assure our customers that they don't need to use bottled water or boil their water," said Chris Graziano, vice president and general manager, in a prepared statement. "All public water systems that use chlorine as a disinfectant contain trihalomethanes to some degree." Laboratory results showed that the average trihalomethane levels were 80.6 parts per billion (ppb) and 84.2 ppb, slightly above the 80 ppb standard set by the U.S. Environmental Protection Agency.

The water treatment process includes adding chlorine to destroy harmful bacteria. Graziano said the use of chlorine is considered one of the greatest public health advances of the 20th Century. Chlorine prevents water-borne illnesses such as typhoid or cholera. According to the World Health Organization, the risk of illness and death from untreated water is very much greater than the risks of disinfection byproducts.

Disinfection byproducts are more likely to occur when surface water is used as the source for drinking water. About 30 percent of SUEZ's source water is surface water while the balance comes from wells. "We have provided the Rockland County Department of Health with the steps we are taking to lower levels at those locations," said Graziano. "This includes using more groundwater and less surface water in the affected area." He added that ongoing testing shows that the water meets all other safe drinking water standards.

The same thing happened to Nyack water in February.

On Feb. 19, village water samples showed elevated levels of Trihalomethanes -- and Nyack officials issued an alert.

Rockland County officials issued this statement Wednesday: Suez has recently issued a notice informing their customers about an MCL Violation (maximum containment level) for Total Trihalomethanes in their water system. The language in their notice was largely prepared by the New York State Department Health to inform everyone about the levels found in the water, why it is important to monitor for them, and what is being done to respond. The details can be found in the notice on Suez website: http://www.mysuezwater.com/new-york/standard-home.