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.
- To view all 29 Questions and Answers PDF (29pp, 211K)
Basic information about chloramines and drinking water disinfection
- What are chloramines? PDF (1p, 26K)
- How long has monochloramine been used as a drinking water disinfectant? How is monochloramine typically used? How many people/water utilities use monochloramine? PDF (1p, 27K)
- Why is drinking water disinfected? What is the difference between primary and secondary disinfection? How is monochloramine used in a treatment plant? (PDF) (1p, 28K)
- What disinfectants are available for drinking water? (PDF) (1p, 19K)
- How effective is monochloramine vs. chlorine as a primary disinfectant? (PDF) (1p, 23K)
- How effective is monochloramine vs. chlorine as a secondary disinfectant? (PDF) (1p, 25K)
Water systems, disinfection byproducts, and the use of monochloramine
- Why are disinfection byproducts a public health concern? (PDF) (1p, 23K)
- How does EPA regulate disinfection byproducts (DBPs)? (PDF) (1p, 27K)
- How do the kinds and concentrations of disinfection byproducts formed by monochloramine compare to those formed by chlorine? (PDF) (1p, 25K)
- Why are water utilities switching to monochloramine? (PDF) (1p, 23K)
- Other than chlorine and monochloramine, what options could water utilities consider to control the levels of disinfection byproducts? (PDF) (1p, 23K)
- Does EPA require water utilities to use monochloramine? Who approves the decision for a water utility to use monochloramine? (PDF) (1p, 22K)
- What assistance does EPA provide to water utilities that are considering a switch from chlorine to monochloramine? (PDF )(1p, 24K)
- How did EPA evaluate the safety of monochloramine for use as a drinking water disinfectant? (PDF) (1p, 24K)
- Why does EPA believe that sufficient research has been conducted to approve the use of monochloramine as a drinking water disinfectant? (PDF) (1p, 27K)
- Why does EPA believe monochloramine is safe and appropriate to use? (PDF) (1p, 26K)
- What does EPA see as the advantages of using monochloramine? (PDF) (1p, 23K)
- What does EPA see as the disadvantages of using monochloramine? (PDF) (1p, 26K)
- What is EPA’s current focus regarding chloramines research? What other ongoing research is EPA aware of? (PDF) (1p, 29K)
Common health questions related to monochloramine
- Is it safe to drink and cook with chloraminated water? (PDF) (1p, 28K)
- Can I shower in or use a humidifier with chloraminated water? (PDF) (1p, 23K)
- Can chloraminated or chlorinated water be used for dialysis or in an aquarium? (PDF) (1p, 22K)
- Does monochloramine cause cancer? (PDF) (1p, 23K)
- Does monochloramine cause skin problems? (PDF) (1p, 24K)
- Do chloramines cause breathing problems? (PDF) (1p, 26K)
- Does monochloramine cause digestive problems? (PDF) (1p, 26K)
- Does monochloramine change water chemistry? Does monochloramine use contibute to the release of lead or other contaminants into drinking water? (PDF) (1p, 29K)
- How can I remove monochloramine from my drinking water? (PDF) (1p, 23K)
- Can my doctor tell if my health problems are caused by monochloramine or any other disinfectant in drinking water? (PDF) (1p, 24K)
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:
- EPA’s Integrated Risk Information System (IRIS) Web site.
IRIS includes updated information up to 2005 for the oral and carcinogenicity assessments for chloramine (assessment found under heading monochloramine).
- Drinking Water Health Criteria Document for Chloramines, (155pp, 2M, About PDF)
Health and Ecological Criteria Division, Office of Science and Technology, Office of Water, EPA, 1994. [Note: This document is currently being revised]
- Stage 1 Rule page has further information on exposure and occurrence and summarizes of health information used to set the current chloramine standard.
- Stage 2 Rule Web site has further information on disinfection practices and explains risk-risk tradeoffs associated with disinfection byproducts and pathogen control.
To reach EPA for more information:
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
- 2007 Version of Chloramines Q&A’s PDF. (7pp, 236K)