History of Monochloramine Use  

• It is likely that monochloramine formed in wastewater and in waters containing natural ammonia for some time before the term “chloramine” existed.
• In the early 1900s, the chlorine-ammonia combination received attention when it was found that the cost of chlorination might be reduced if ammonia was added.
• The practice of monochloramine treatment was adopted in 1916 at the treatment plant in Ottawa, Ont.
• The first installation in the United States was in 1917 in Denver, Colo. Both locations used ammonia and hypochlorite and noted improvements in taste . 
  
  Water Utilities with a Long History of Monochloramines Use

City	Approximate Start of Monochloramination
Denver, CO	1917
Portland, OR	1924
Massachusetts Water Resources Authority	1932
St. Louis, MO	1934
Portland, ME	1938
Boston, MA	1944
Indianapolis, IN	1954
Minneapolis, MN	1954
Dallas, TX	1959
Kansas City, MO	1964
Milwaukee, WI	1964
Philadelphia, PA	1969
Houston, TX	1982
Miami, FL	1982
San Diego, CA	1982

 

 

 

 

 

 

 

 

 

Source: Trussel and Kreft

• More than 400 utilities were using monochloramine disinfection by 1938. During World War II, when ammonia supplies were low, the use of monochloramine was reduced.
• Monochloramine was used sparingly until the 1970s when the potentially harmful disinfection byproducts trihalomethanes (THMs) were discovered. Depending on local circumstances, monochloramine produces fewer THMs than free chlorine does, so the use of monochloramine increased. Haloacetic acids (HAAs), another set of disinfection byproducts, were regulated in 1998, further supporting the use of monochloramine.