Top-Rated Water Filters: Clear Leaders

Pitchers • Faucet-Mount • Countertop • Under-Sink • Showerhead

Finally, a standard exists for evaluating whether water filters are capable of reducing trace amounts of contaminants, such as pharmaceuticals, from drinking water. However, scientists and experts disagree over whether low levels of these contaminants pose a health threat in the first place.

Email to a Friend


It took 6 years, but in August 2014, National Sanitation Foundation (NSF) and industry experts finally introduced a certification standard to evaluate the capability of water filters to reduce levels of so-called emerging contaminants that are in drinking water.

The new standard, NSF/ANSI 401, addresses 15 contaminants, including herbicides, manufacturing chemicals, over-the-counter medications, pesticides and pharmaceuticals. Previously, NSF/ANSI standards in drinking water existed in regard to killing microorganisms. (For a complete list of contaminants that the new standard covers, see “Drinking Water’s New Standard.”)

Despite the new standard, however, no consensus exists on whether trace levels of these contaminants in drinking water pose any threat to public health.

Rick Andrew of NSF tells us that research to identify and understand the “thousands of different chemicals that could be in the water” will take “many years.” He says NSF Joint Committee on Drinking Water Treatment Units will expand NSF/ANSI 401 to include more contaminants in the coming years.

“Understanding the toxicological significance of these compounds and contaminants in the drinking water at low concentrations will take quite some time and study,” Andrew tells Consumers Digest.

As of press time, 122 water-filtration systems from 16 companies were certified by NSF to meet the new standard. They start at $45.

For peace of mind, “you don’t want to be ingesting any of these things,” says Zack Schroeck of manufacturer Culligan International. No Culligan products are certified to meet the new standard. “In most cases, it’s been found that there’s not that much of [the contaminants] in water,” Schroeck says.

BACTERIA PROTECTION. Waterlogic also doesn’t make a water-filtration system that’s certified to meet the NSF/ANSI 401 standard. Nevertheless, the company says “no other drinking-water purifier” delivers the same purity as its 2-year-old countertop Hybrid Water Purifier ($199). In the Hybrid, water flows through an active-carbon filter that reduces contaminants, such as chlorine and lead. This is conventional. However, the water then travels through a quartz spiral where it’s exposed to ultraviolet (UV) light that the company says destroys bacteria. This makes the Hybrid the only countertop water-filtration system that we found that uses UV light, and the model meets the NSF P231 protocol for microbiological purity and the NSF/ANSI 55 Class A standard for UV microbiological water-treatment systems. We found a few under-sink water-filtration systems that incorporate UV light, but they typically cost at least $1,000.

Waterlogic says UV light is necessary, because when a water filter removes chlorine from drinking water (as they all do), it also removes protection against bacterial growth inside of the water filter, says Moshe Gazit of Waterlogic. “Our philosophy is that just filtering the water is not enough,” he says.

Drinking Water’s New Standard

Read Now

Before you start to worry about whether microbiological contaminants form in your filtered drinking water, you should relax. Experts tell us that microbiological contaminants are a concern in the drinking-water systems of some developing countries but not in the United States, at least not on a regular basis.

“Thankfully, we don’t have to worry about bacteria as much as other parts of the world,” says Matt Chilton of ZeroWater.

Waterlogic agrees that bacteria is a bigger problem in developing countries than in the United States, but the company says it wants to provide as many safeguards as possible against bacteria and chemicals.

Andrew agrees. He says microbiological safeguards are useful when a boil advisory exists because of a broken water main or pipe. Furthermore, private-well owners occasionally have problems with contamination. Finally, drinking-water sources, such as lakes and rivers, can be contaminated with cryptosporidium, which is resistant to chemical disinfectants and can cause gastrointestinal issues. If you draw water directly from a lake or river, a certified microbiological-treatment water-filtration system will prevent exposure to cryptosporidium, Andrew says.

“We’ve looked into a bacteria-killing solution, but I don’t think it would be for home use,” Shelton says. “It would be used either while you’re camping or in an emergency situation.”

No other company tells us that it’s developing a similar UV water-filtration system.

Water-Filtration Bottles: Clean Water On The Go

Read Now

IN OR OUT? We noticed that some manufacturers of water-filtering appliances now claim that their various filters leave more naturally occurring minerals (or dissolved solids) in drinking water than do the filters of their competitors. That’s notable, because typically the companies that make water filters claim that their filters remove more contaminants than do those of their competitors.

Aquasana, WaterChef and Waterlogic say their products use selective filtration to retain calcium, magnesium and potassium, which are valuable minerals.

“Some manufacturers have done an effective job of making consumers believe that dissolved solids are a bad thing,” says Derek Mellencamp of Aquasana. “We make a point to create technology that leaves the healthy minerals in there.”

Conversely, ZeroWater makes a point of taking out as many solids as it can. The company says its products (starting at $26) deliver water that registers a reading of zero parts per million on a Total Dissolved Solids (TDS) meter, which is included with ZeroWater products but typically costs $30. Any company’s reverse-osmosis water filter also removes all dissolved solids. Reverse-osmosis filters start at $200.

“The idea of keeping minerals in the water is brought up from time to time, but water goes through so many processes before it gets to your tap that it’s difficult to know where the minerals are coming from,” Chilton says.

So, are the naturally occurring minerals that are in drinking water good or bad for you? That’s difficult to answer, according to NSF and Water Quality Association, which represents the water-treatment industry.

Generally, experts consider calcium, magnesium and potassium to be beneficial for bone and heart health, but most people who have a healthful diet get far more calcium, magnesium and potassium from their food than they do from their drinking water, Andrew says. Fluoride generally is considered to be beneficial for teeth, but experts say too much fluoride can be detrimental.

“There is no easy answer to this one, and it depends entirely on the person’s preferences and their water-supply profile,” Andrew says.

If you wonder about the levels of minerals that are in your drinking water, you won’t find the answers in your public-water supplier’s consumer confidence report, which is an annual report that Environmental Protection Agency requires to be made public for free. EPA has no guidelines for the levels of TDS that can be in drinking water, because the agency believes that TDS levels are an aesthetic issue that merely affects the color, odor and taste of water rather than a health issue.

Andrew tells us that the best way to learn about the amount of TDS that’s in your drinking water is to have an EPA-certified laboratory test your water. You can find a list of certified labs at

That should quench your curiosity.

Robert E. Calem has reported about water filters for 29 years. His work has been published in The New York Times and The Wall Street Journal.

Back to Article