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Drinking Water Disinfection and the Free Chlorine Conversion Process FAQs
Download Chlorine Conversion FAQ (PDF).
1. Why is drinking water disinfected?
Disinfecting drinking water is critical to protecting consumers from disease-causing microorganisms, called pathogens, including bacteria or viruses. Disinfectants are very effective at inactivating (or killing) pathogens and have enormously benefited public health. For example, the incidence of typhoid fever was reduced by 1000-fold in the US in the last century by implementing the disinfection of drinking water.
2. What is chloramine?
Chloramine is a long-lasting disinfectant added to public drinking water for disinfection. It is formed by combining chlorinated water with small amounts of ammonia. It is commonly used for disinfection in many public water systems throughout Texas, the United States, and countries around the world.
3. Is chloramine safe?
Yes, water disinfected with chloramine is safe for drinking, cooking, bathing, and everyday use. The U.S. Environmental Protection Agency (USEPA), the Centers for Disease Control, and the World Health Organization have determined that chloramine is a safe disinfectant and that water disinfected with chloramine within regulatory standards has no known or expected adverse health effects.
4. What is a free chlorine conversion (“chlorine burn”)?
A free chlorine conversion (also referred to as a “chlorine burn”) occurs when a water system that typically uses chloramine removes ammonia (needed to form chloramine) from the treatment process, and disinfects the water with only chlorine. Chlorine is more effective than chloramine at inactivating certain types of bacteria.
5. Why is my public water system using chloramine?
Chloramine is an effective disinfectant and persists over a long period of time, particularly in areas with high temperatures. This makes chloramine very useful in Texas’ large distribution systems such as those of cities with numerous connections and in rural water systems with fewer connections spread out over a large geographic area.
6. Why is my water system conducting a free chlorine conversion?
A free chlorine conversion is typically conducted for two primary reasons:
- It is often conducted as a preventative maintenance measure to kill bacteria that can make the maintenance of disinfection residual problematic.
- The conversion to free chlorine, in conjunction with increased flushing activities, assists in removing excess film from the distribution system and also starves these bacteria. The chlorine conversion helps the system return to an environment where the disinfectant residual can be maintained.
7. Are there any disadvantages to a free chlorine conversion?
Properly conducted free chlorine conversions can often cause the water to have a different taste and/or odor than when using chloramine for disinfection. Customers will likely be able to notice the difference, but there are no health effects associated with the change in taste/odor. Once the water system has returned to using chloramine as the disinfectant, the taste/odor of the water will return to normal
8. What are the drinking water disinfection requirements in Texas?
Public water systems are required to disinfect water prior to its entering the distribution system that carries it through pipes for delivery to consumers. Public water systems in Texas are also required to maintain a minimum amount of residual disinfectant throughout the distribution system to make sure that harmful microorganisms stay low. Treatment prior to distribution may utilize a number of different disinfectants, but a public water system is required to use either chlorine or chloramine in the distribution system.
