Disinfection Byproducts (DBPs)

Drinking water utilities play a central role in protecting public health by treating and disinfecting drinking water. DBPs are formed when chemical disinfectants used to treat drinking water react with naturally occurring materials in the water. All commonly used disinfectants form DBPs.

Why are DBPs a health concern?

Research on animals has found increased occurrence of cancer development from high concentrations of DBPs exposure, although why this occurs has not yet been determined. Research on the relationship between DBPs and cancer and other health risks is ongoing.

Over the past several years, a handful of studies also have shown a possible link between high levels of DBPs in tap water and adverse effects on reproductive health, including low birth weight and miscarriage. Other studies have failed to demonstrate such a linkage.

Experts agree that the research on DBPs and health effects is preliminary and inconclusive, and additional research is still needed.

If DBPs are a health concern, why disinfect drinking water? Why not use disinfection that does not produce byproducts?

Disinfection of drinking water is vital to protecting the public against disease. In countries without adequate disinfection, thousands of people die every day from waterborne diseases. The filtration and disinfection of drinking water is widely acknowledged to be responsible for a large part of the 50 percent increase in life expectancy in the 20th century. Both the World Health Organization and the U.S. Centers for Disease Control and Prevention describe water filtration and disinfection as among the most significant advancements of the last century.

All chemical disinfectants cause DBPs. Protecting the public from disease calls for strong disinfectants that do their job from the treatment plant, through the distribution system pipes, all the way to consumers' homes. Only chlorine-based disinfectants can protect water quality through the distribution system.

How is the water community responding to the DBP issue?

Protecting public health is the top priority for water suppliers. Efforts began in the late 1970s to manage potential health risks associated with DBPs without compromising disinfection. While the research on the health risk from DBPs is ongoing and, to date, inconclusive, utilities are working to achieve DBP reductions. The water community has funded and continues o fund research to understand DBP occurrence, health effects, and treatment.