I am also amazed by what they add also, and now they add chloramine because it lasts longer when just chlorine tends to dissipate in the pipes.
Great points!
theberkeyguy
Chloramine was first used in the San Francisco water system in 1935. It was discontinued in 1944 due to an ammonia shortage in WWII. It was reintroduced into the system in 2004.
The re-introduction of chloramine in 2004 was dues to new EPA regulations that required public utility water systems to drastically lower their maximum trihalomethane (THM) content.
THM's are the natural chemical reaction byproducts of mixing water and chlorine. When the new standards came out, several public systems went to Chloramine, which is a compound of chlorine and ammonia, because it produces less THM's during the water disinfection process.
That's the simple version. It's way more complicated.