Why is Water Line Chlorination necessary?

Chlorination Rules

There are two agencies that write the rules for chlorination. One is the American Water Works Association, referred to most commonly as AWWA, and California law via California plumbing code. AWWA C651 is the procedure designed for disinfection of water mains, specifically underground water lines. California Plumbing code is a much more broad code which doesn’t delineate underground water lines from building water lines. The California Plumbing code section about chlorination is 609.9 which stipulates that any newly repaired or installed water lines need to be disinfected in order to ensure they are sanitary and bacteriologically safe for normal use. So, if we are chlorinating underground water lines, we generally follow AWWA C651 procedure, and if we’re chlorinating building water lines we follow CPC 609.9.

History of Water Chlorination

Americans take safe drinking water for granted today. Just over a century ago, water chlorination wasn’t standard practice. Surprisingly, the use of chlorine to purify water began with chlorinating water for animals.

Regular chlorination of water for human consumption didn’t take hold in the US until the early 20th century. In 1908, Dr. John Leal, a devoted physician and public health advocate, pioneered mass chlorination in Jersey City, New Jersey. His chlorine disinfection system successfully eliminated harmful pathogens and curbed disease outbreaks. That same year, George Johnson implemented a similar chlorination process for Chicago’s water supply. Impressed by the dramatic results, cities nationwide followed suit by the 1920s.

Once a deadly threat, the typhoid epidemic is now rarely a concern thanks to chlorine. Studies show that chlorination and filtration reduced typhoid fever rates by a staggering 91%, leading to near eradication by 1936.