Common Drinking Water Contaminants

Though adequate water sanitation exists in many communities, some places in the US lack the infrastructure to provide clean drinking water to their residents. Even in areas where proper treatment exists, tap water may contain small amounts of emerging contaminants that are unregulated by the Environmental Protection Agency (EPA), including some pesticides and pharmaceuticals, microplastics, and PFAS chemicals. In addition, media coverage of extreme events in Philadelphia, Camp Lejeune, and East Palestine, Ohio is raising awareness about water contamination issues, leaving many to wonder—is the water I’m drinking safe? Home water filtration systems may help improve the safety and quality of your drinking water. While they shouldn’t be used on water that local officials say is unsafe to drink, they can help reduce exposure to potentially harmful contaminants and provide some peace of mind.

A note on shopping for water filtration systems.

Before you hit that buy button, be sure that the water filter that you’re interested in is certified by a trustworthy third-party organization, like the National Sanitation Foundation (NSF) or the American National Standard Institute (ANSI). These certifications exist to help you verify brand and manufacturer claims about water filtration and should be listed on product websites and packaging.

Heavy metals lead, arsenic, and more,

Filtration solution: Systems that carry activated carbon filters.

PFAS forever chemicals.

Filtration solution: Systems that hold NSF/ANSI 53 certification.

Emerging contaminants and microplastics.

Filtration solution: Systems that hold NSF/ANSI 401 certification.

Chlorine and chloramines.

Filtration solution: Systems that hold NSF/ANSI 42 certification.

What types of water filters reduce heavy metals?

Activated carbon filters have been proven most effective in reducing heavy metals.

Heavy metals is an umbrella term for a range of dense metallic elements. Some—like iron and zinc—are only harmful in higher quantities and are important for human health when consumed at proper levels. Others, like arsenic, are just plain toxic, possibly even at low concentrations.

Municipal water sources and private wells can be contaminated by heavy metals through old pipes, improper manufacturing disposal, landfill runoff, and more.

High doses of heavy metals can be harmful in many ways and can impair brain, liver, and kidney function. Repeated exposure has been linked to various cancers and neurological disorders, including Parkinson's disease and Alzheimer's.

The most reliable way to reduce heavy metals in drinking water is to use an under-sink water filtration system equipped with activated carbon filters.

These charcoal-based filters have been chemically altered to contain a multitude of tiny pores, which help trap contaminants in water—like heavy metals— through a process called adsorption.

What types of water filters reduce PFAS chemicals?

Systems that hold NSF/ANSI 53 certification have been proven most effective in reducing PFAS chemicals.

Think of that non-stick pan in your cupboard or the waxy surface of a fast-food box and you’ll have a good idea of how to spot PFAS forever chemicals in the wild. Short for per- and polyfluoroalkyl, these synthetic chemicals can be found in things we use every day, like cookware, waterproof apparel, skincare and cosmetics, and more.

Since they’re pretty much everywhere, they’re almost impossible to avoid—and can even contaminate the water you drink. Forty-five percent of tap water in the United States contains PFAS, according to a recent U.S. Geological Survey report.

That may not be a good thing for our health. Evidence suggests that PFAS chemical exposure may increase the risks of certain types of cancer, reproduction and fertility issues, and developmental effects in children.

Fortunately, getting the right water filtration system can help reduce your exposure. Countertop, under-sink, or reverse osmosis filtration systems that hold NSF/ANSI 53 certification can reduce PFAS by up to 99 percent.

What types of water filters reduce emerging contaminants and microplastics?

Systems that hold NSF/ANSI 401 certification have been proven most effective in reducing emerging contaminants and microplastics.

The EPA is tasked with regulating water standards and ensuring what’s coming from your tap is safe to drink. But new types of contaminants are being discovered in drinking water every year and it can be difficult for regulators and scientific researchers to keep up.

Pollutants that fall under this category are called emerging contaminants and include many things you don’t want to drink, including pharmaceuticals and over-the-counter drugs, pesticides, microplastics, and more.

Scientists are currently working to figure out how emerging contaminants and microplastics impact the human body. Still, there is growing concern about long-term exposure to pharmaceuticals, pesticides, and industrial chemicals. The same can be said about microplastics, which may negatively affect bodily processes—including the reproductive system—and increase the risk of heart attack and stroke.

You won’t find a filter that reduces all emerging contaminants. However, a countertop, under sink or reverse osmosis system that holds NSF/ANSI 401 certification ensures the reduction of up to 15 emerging contaminants, including industrial chemicals like Bispherol A (BPA), pesticides like DEET, and more. Systems that hold this certification will also help to reduce your exposure to microplastics.

What types of water filters reduce chlorine and chloramines?

Systems that hold NSF/ANSI 42 certification have been proven most effective in reducing chlorine and chloramines.

These disinfectants differ from the others on this list because they are intentionally added by sanitation departments to kill microorganisms in drinking water.

The EPA regulates the levels of chlorine in water, and in those quantities, they’re generally agreed to be safe for human consumption.

That said, these cleaning agents can give water a chemical taste and odor that many find unpleasant. To reduce these sanitizers and improve the aesthetic quality of your water, get a countertop, under sink or reverse osmosis system that holds NSF/ANSI 42 certification.

How do I find out what water contaminants exist in my area?

Check with your local or state water sanitation department to learn about the quality of your tap water. Another helpful tool is the Environmental Working Group’s Tap Water Database, which will provide information on your water supply based on your zip code.