Disinfection is an essential component of public drinking water treatment. Chlorine in any form (powder, liquid, or gas) both disinfects drinking water and minimizes microbial growth in the water distribution system.
Disinfection by-products form when chlorine is added to water that contains elevated levels of natural organic matter such as decaying leaves and vegetation. High levels of disinfection by-products levels are common for surface-based public water supplies in Newfoundland and Labrador because many of them contain high levels of natural organic matter. The health risks from disinfection by-products are much less than the risks from consuming water that has not been appropriately disinfected.