Disinfection Byproducts

To protect public health, the EPA creates national regulations. These drinking water standards are enforced by VDH in Virginia. Prince William Water sends VDH its water quality test findings monthly and annually to ensure the utility fulfills federal and state drinking water regulations. If a water quality violation occurs, Prince William Water must notify VDH and its customers immediately and work with VDH to correct it.

Fairfax Water, which supplies most Prince William Water drinking water, disinfects with ozone and chloramines. Some of our western Prince William clients get drinking water from Manassas, which disinfects using chloramines. In spring, Prince William Water's water providers clean drinking water with free chlorine, a stronger disinfectant, to prevent bacteria from developing resistances.

Free chlorine and chloramines react with organic materials like decaying plant material in water to generate disinfection byproducts (DBPs). EPA and VDH regulate DBPs, Total Trihalomethanes (TTHM) and Haloacetic Acids (HAA5).  

TTHM and HAA5 sample results in Prince William Water's distribution system are regularly below the EPA standard, which Virginia Department of Health enforces.  

Certain cancers have been linked to chronic DBP exposure. The World Health Organization estimates that aquatic microorganisms pose 10,000 to 1 million times the risk of cancer from DBPs. Chloramines produce less DBPs than free chlorine because their chemical nature makes them less reactive to organic materials.