What's Best: A Whole-House or Under-Sink Water Filter?

The answer depends on your family's needs

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Parent holding a baby while filling up a glass from the kitchen tap.
Choosing the right filter for your home is essential, just like clean water.
Photo: David Oxberry/Getty Images

Did you know that boiling water removes some bacteria but not contaminants like chlorine and lead? In fact, boiling water can actually elevate its lead concentration.

If your goal is to have filtered water for drinking and cooking, an under-sink water filter is probably all you need. Those certified to the NSF/ANSI 42 standard effectively remove odors and off-tastes, and filters certified to the NSF/ANSI 53 standard remove lead and other contaminants.

If your annual water-quality report shows you have a wide range of contaminants or bacteria in your water, a reverse osmosis water filter is your best bet. These filters force water through a semi-permeable membrane to wall off synthetic chemicals like PFAS (Polyfluoroalkyl substances or “forever chemicals”) which have been linked to cancer, high cholesterol and learning delays in children.

More on Water Filters

Whole-house water filters (different from softener systems for hard water) are best for removing large sediment, such as sand and iron. (The latter can stain sinks and clothing.) These water filters can also improve the taste of your water, but the most basic ones don’t filter for the contaminants that under-sink water filters do.

"Some advanced whole-house purification systems can remove potential hazards such as volatile organic compounds [VOCs], pesticides, and heavy metals, but they’re expensive—and can be overkill," says John Galeotafiore, associate director of product testing at CR. For example, you probably don’t need filtered toilet water.

If you’re worried about sediment as well as contaminants, Galeotafiore recommends pairing a basic, less expensive whole-house water filter with an NSF/ANSI-certified point-of-use water filter for the water you ingest.

For filtering large capacities of water over time, standard under-sink water filters also do an effective job of removing contaminants. All eight recently tested options in our under-sink filter ratings are certified to NSF standards for reducing lead and chlorine from water. And all but one earn an Excellent rating in our test for improving flavor and reducing odors, even if some take longer to filter.

Check our water filter buying guide for more information, and see our water filter ratings for an in-depth look at how each model performs in our tests. Here, CR members can see ratings our four top-rated under-sink water filters, listed in alphabetical order:

What’s in Your Water?

Do you have bad-tasting water? Consumer Reports’ Perry Santanachote and James Dickerson explain how to find out about water testing and the best filtration systems.

Editor’s Note: A version of this article also appeared in the May 2020 issue of Consumer Reports magazine.