2/24/2009 US EPA

BASIC INFORMATION ABOUT CHLORAMINES

2) How long has monochloramine been used as a drinking water
disinfectant? How is monochloramine typically used? How many
people/water utilities use monochloramine?

Monochloramine has been used as a drinking water disinfectant for more
than 90 years}

•	Monochloramine has been shown to be an effective disinfectant based on
decades of use in the U.S., Canada, and Great Britain.

•	Monochloramine is typically used along with chlorine as part of the
drinking water treatment process.

•	Monochloramine helps protect people from waterborne diseases.2

Monochloramine is most often used to maintain water quality in the pipes 3

•	Monochloramine provides long-lasting protection of water quality.

•	Monochloramine is effective as a disinfectant because it does not
dissipate quickly

•	Monochloramine helps lower levels of potentially harmful regulated
disinfection byproducts compared to chlorine.

More than one in five Americans use drinking water treated with
monochloramine.

•	Monochloramine use has increased in recent years due in part to new
drinking water regulations developed to limit certain disinfection
byproducts.

•	New drinking water regulations limit the concentration of potentially
harmful disinfection byproducts that may occur in drinking water.4

•	Several large cities such as Denver and Philadelphia have been using
monochloramine as part of their treatment process for decades.

Additional Supporting Information:

1.	For more information on the history of drinking water disinfection visit:
http://www.epa.gov/safewater/consumer/pdf/hist.pdf.

2.	For more information on waterborne disease visit:
http://www.cdc.gov/ncidod/diseases/list waterborne.htm.

3.	Drinking water is typically treated before it is passed through the pipes, however, water is not
sterile and can contain low levels of microorganisms that survive through treatment and
distribution. Microbes can grow on pipe surfaces forming a thin biofilm layer. These microbes,
while typically not harmful, can contribute to various problems, including (1) the release of
coliform bacteria into the water, (2) increased disinfectant demand, (3) aesthetic water quality
problems (e.g., unpleasant taste or odor), and (4) pipe corrosion or nitrification reactions and the
resulting release of contaminants such as nitrite, nitrate, and lead into the water. See question 27
for more information on contaminant release, biofilms, and nitrification. In some cases, biofilms
have been known to harbor pathogens that cause disease, especially in severely
immunocompromised persons. See Drinking Water Distribution Systems - Assessing and
Reducing Risks—chapters 6 and 7, http://www.nap.edu/catalog.php7record id=11728#toc

Also see EPA's Biofilm White Paper:

http://epa.gov/SAFEWATER/disinfection/tcr/pdfs/whitepaper tcr biofilms.pdf.

4.	See the Stage 1 and Stage 2 Disinfection Byproduct Rules for more information on new
drinking water regulations (http://www.epa.gov/safewater/disinfection/index.html').

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