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Water: Microbial & Disinfection Byproducts Rules

Chloramines in Drinking Water

Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. The typical purpose of chloramines is to provide longer-lasting water treatment as the water moves through pipes to consumers. This type of disinfection is known as secondary disinfection. Chloramines have been used by water utilities for almost 90 years, and their use is closely regulated. More than one in five Americans uses drinking water treated with chloramines. Water that contains chloramines and meets EPA regulatory standards is safe to use for drinking, cooking, bathing and other household uses.

Many utilities use chlorine as their secondary disinfectant; however, in recent years, some of them changed their secondary disinfectant to chloramines to meet disinfection byproduct regulations. In order to address questions that have been raised by consumers about this switch, EPA scientists and experts have answered 29 of the most frequently asked questions about chloramines. We have also worked with a risk communication expert to help us organize complex information and make it easier for us to express current knowledge.

The question and answer format takes a step-wise approach to communicate complex information to a wide variety of consumers who may have different educational backgrounds or interest in this topic. Each question is answered by three key responses, which are written at an approximately sixth grade reading level. In turn, each key response is supported by three more detailed pieces of information, which are written at an approximately 12th grade reading level. More complex information is provided in the Additional Supporting Information section, which includes links to documents and resources that provide additional technical information.

EPA continues to research drinking water disinfectants and expects to periodically evaluate and possibly update the questions and answers about chloramines when new information becomes available.

You may wish to view each question separately by clicking on the highlighted questions below or may wish to view them as one document.

Basic information about chloramines and drinking water disinfection

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Water systems, disinfection byproducts, and the use of monochloramine

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Chloramines-related research

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Common health questions related to monochloramine

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More information about your drinking water

EPA strongly encourages people to learn more about their drinking water. Your water bill or telephone book’s government listings are a good starting point for local information. Water systems have several different choices when it comes to disinfection. To find out if chloramines are used in your community, contact your local water system.

EPA requires all community water systems to prepare an annual consumer confidence report (CCR) (sometimes called a water quality report) for their customers. The CCR lists the level of contaminants that have been detected over a certain period of time and shows how these levels compare with EPA’s drinking water regulations. Some water suppliers have posted their annual reports on EPA’s Website. If you have not received this annual report, and it is not posted on EPA’s Website, you may request it by calling your water system.

More information about chloramines and disinfection byproducts

More information about health effects and drinking water disinfection from EPA is available in the following locations:

To reach EPA for more information:

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2007 Version of Chloramines Q&A’s

EPA has updated the previous version of the Chloramines Q&A’s in order to better communicate complex issues to a wider audience. EPA expects to continue to review and possibly update the Q&A’s on a periodic basis or as new information becomes available

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