Let us start by saying that generally, in the U.S. public water is well-regulated and is, for the most part, safe to drink. That’s not to say that there aren’t any impurities that make it into your water supply in trace amounts. “Drinking water supplies in the United States are among the safest in the world. However, even in the U.S., drinking water sources can become contaminated,” notes the Centers for Disease Control and Prevention (CDC).
In particular, people on well water in more rural areas could have a higher risk of health impacts from contaminants in their tap water, making regular testing important. That being said, here are seven substances found in municipal and well water that may warrant a water purifier at home if you’re concerned…
The Environmental Protection Agency (EPA) offers a table of regulated drinking water contaminants, adding the “National Primary Drinking Water Regulations (NPDWR) are legally enforceable primary standards and treatment techniques that apply to public water systems.”
That being said, contaminants including Cryptosporidium and Giardia lamblia (generally in private wells) from fecal matter can make their way into water supplies, causing gastrointestinal illnesses and cramps from long-term exposure, notes the EPA.