Disinfection of drinking water is one of the major reasons why cholera and typhoid are no longer common epidemics in America. Drinking water disinfectants, such as the chlorine used by Providence Water, are a low cost, highly effective means for protecting public health. However, disinfectants can react with naturally occurring compounds in water to produce by-products which may be detrimental to public health.

The Disinfectants and Disinfection By-Products Rule (DDBP) is a 1998 amendment to the SDWA that was developed to balance the risks associated with microbial pathogens against those risks associated with disinfection by-products. The DDBP Rule establishes maximum allowable levels for disinfectants commonly used by drinking water suppliers and for the disinfection by-products arising from their use. Below is a table listing the regulated standards applicable to Providence Water and how our water stands in comparison:

  Max. Allowable Level Providence Water
Disinfectant Residual
Chlorine 4 ppm 0.30 ppm
Disinfection By-Product
Total Trihalomethanes 80 ppb 30 ppb
Haloacetic Acids 60 ppb 15 ppb
Chlorite 1 ppm None Detected
Bromate 0.01 ppm None Detected

In addition to reducing disinfectant and disinfection by-products, large systems, such as Providence Water are required to take action to remove specific percentages of those naturally occurring materials which combine with disinfectants to produce disinfection by-products. Removal is achieved through enhanced coagulation treatment techniques.