Chlorine vs. chloramine: what your water utility adds and why

Water from a city system is disinfected twice: once at the treatment plant and again with a "residual" disinfectant that keeps the water protected as it travels through miles of pipe to your home. That residual is almost always chlorine or chloramine.

What is chloramine?

Chloramine is formed by adding ammonia to chlorine. It lasts longer in the pipes than chlorine alone, which is why many utilities use it as their secondary disinfectant. [1] In the U.S., about 113 million people receive water treated with chloramines. [1] The Massachusetts Water Resources Authority, which supplies Boston, is one of the utilities that uses it. [2]

How do I know which one my utility uses?

Your utility lists its disinfectant in the annual water quality report (also called the Consumer Confidence Report, or CCR). Our free water report also reads the official EPA records for your ZIP code.

What reduces chlorine and chloramine at home?

Activated carbon reduces both chlorine and chloramines, along with compounds that cause taste and odor. [3] That is why carbon stages appear in whole house systems, reverse osmosis pre-filters and many shower filters.