Everyone can benefit from a water filter, according to Lilli Link, MD a board-certified internist and functional medicine practitioner at Parsley Health New York. Though there’s recently been much publicity about water contamination in cities like Flint, Michigan or Chicago, Illinois where lead has seeped into the water system and caused serious long-term damage to the health of many residents, the fact remains that even seemingly “clean” sources of water contain substances that could be harmful to your wellbeing, she adds.
All water contains a wide array of substances that range in impact on the human body. Some—like lead—can pose serious health risks. Others are far less threatening, especially in small quantities. But here in the United States, water generally goes through a significant filtration process before it winds up coming out of the faucet for us to drink.

How is your water filtered before it reaches your sink?
Local municipalities are responsible for tap water filtering (assuming it doesn’t come from a well, which is generally believed to be safe to drink due to the ground’s natural filtration abilities). During this process, Dr. Link explains, most dirt, dust, heavy metals and microbes are removed. Then, most municipalities add chlorine which kills off even more harmful microbes but also adds a chemical to your water source.
Next, the water travels through the city’s piping system to be delivered to sinks in places like homes, office buildings, public water fountains and restaurants. Here’s where things can go wrong. Water can actually pick up contaminants such as lead and copper during this process, depending on the material used to build the pipes, their age, and their maintenance. So it’s possible that you and your neighbor, who get the same local water, could actually end up with completely different contaminants in your water based on your pipes.