The Best Water Filters, According to Our Testing

In the Good Housekeeping Institute, our team of engineers, chemists, product analysts and home improvement experts work together to determine the best water filters for your home. We've tested more than 30 water filters over the years and continue to survey the market for new options.

To test water filters, we take into account their capacity, how easy they are to set up and, if applicable, how easy they are to pour from. We also read each instruction manual for clarity and look at whether pitcher models are dishwasher safe. We test performance factors like how quickly it filters a cup of water and measure how much water the tap water reservoir can hold.

We also verify contaminant removal claims via third-party data. paying particularly close attention to which NSF standard the filters are certified for (some standards cover only lead, like NSF 372, while others also include agricultural and industrial toxins, like NSF 401). We also review how long each filter lasts as well as the yearly cost to replace filters when changing filters on the manufacturer's recommended schedule.

✔️ Type: There are three main options for filtering water for drinking that comes from the kitchen tap.

• Pitcher-style filters are the simplest, most affordable option, but you need to fill them by hand and they can only deliver a certain amount of filtered water at a time.
• Under-sink filters get integrated into your home's plumbing system, delivering filtered water from a dispenser that typically sits next to your kitchen faucet. They're the most unobtrusive way to get filtered water, but also the most expensive.
• Faucet-mounted filters attach directly the kitchen sink; installation is usually tool-free and DIY-friendly. But they look clunky and don't work with popular pull-down faucets.

✔️ Capacity: For pitchers and dispensers that hold water after it’s filtered, pay attention to size and weight. Larger containers mean less refilling, but they're often be heavier and take up space in the fridge. A countertop model saves space in the refrigerator and often holds more water, but it requires real estate on the counter and will be room temperature water.

With under-the-sink and faucet-mounted filters, you don't need to worry about size or capacity because these filter water on demand.

✔️ Filtration method: Many filters incorporate multiple filter types to achieve various contaminant removal. The contaminants they remove can vary widely. The surest way to determine this is by checking which NSF standard the filters are certified for. For example, some standards cover only lead, like NSF 372, while others also include agricultural and industrial toxins, like NSF 401. Otherwise, here are the different water filtering methods:

• Activated carbon is the most common water filter. The carbon-based filter acts like a magnet, absorbing contaminants from the water. Multi-stage filters, or 2-stage filters, might also include a pre-filter to remove larger sediment, as well as a second carbon filter to improve odor and taste. If necessary, sometimes there is even a third filter, maybe with an additional carbon block or a UV sterilizer to kill bacteria and viruses.
• Reverse osmosis (RO) is a newer type of filter that captures contaminants by pushing pressurized water through a semi-permeable membrane. While extremely effective, it's more expensive and less efficient — many systems require a tank that won't fit under your sink. Reverse osmosis filters are only seen with water systems because it needs pressure to work. Our experts first recommend testing your water to determine whether a conventional filter can cover your filtering needs. Most water filters use either a carbon filter or a reverse osmosis water filter, which can also include a carbon filter.
• Ultrafiltration (UF) is another technology you might also hear about. Like RO, it forces water through semipermeable membranes. Because the pore size of the UF membranes is bigger, these systems don't capture all contaminants, including total dissolved solids (TDS) like chlorine and fluoride; we did not review any UF systems for this reason.
• Mineral/alkaline filter adds minerals like potassium, magnesium and calcium. According to the Mayo Clinic, alkaline water has a higher pH level than plain tap water. Some studies also suggest that alkaline water might help slow bone loss. However, further studies are needed to determine whether these benefits are long-term.

✔️ Filter replacement frequency: Check how often you have to replace the filter. If you dread changing the filter or simply forget, you may want to look for a long-lasting filter. Also, if you buy filters for the water pitcher and sink, you’ll have to remember to change each of those separately.

No matter which water filter you opt for, it’s no good if you don’t change the filter as recommended. The performance of the water filter depends on the quality of the water source and whether or not the filters are replaced regularly. Some models come with indicators, but if a model doesn’t include one, a slower flow rate or different-colored water are signs that you need to change the filter.

✔️ Price: Consider both the upfront price of the water filter device and the filter refill costs. A water filter could cost more initially, but the price and frequency of the filter refills may save money over the long term. But that’s not always the case, so be sure to calculate the yearly cost of replacements based on the recommended schedule for changing.

Access to safe drinking water is an issue across the globe, and it affects communities in the U.S. If you’re not sure about your water quality, check the Tap Water Database, managed by the Environmental Working Group (EWG). It’s free and easy to search, and it has information for all states.

Enter your zip code or search your state to find details on your drinking water quality based on EWG standards (which are stricter than those of the government). If your tap water does exceed EWG health guidelines, it may be a good idea to consider buying a water filter.

Opting for bottled water is a short-term solution to potentially unsafe drinking water, but it creates a larger problem with serious long-term implications around pollution. Americans throw away a whopping 30 million tons of plastic a year, only 8% of which is recycled. The majority ends up in landfills because there are many different regulations about what can be recycled. Your best bet is to get a water filter and a reusable water bottle — some even have filters built-in.

This article was first written and tested by Jamie (Kim) Ueda, who is an analyst (and consistent user!) of water filtration products. She’s a freelance writer specializing in product testing and reviews. For this list, she tested several water filters and worked with experts across several Good Housekeeping Institute Labs: Kitchen Appliances and Innovation; Beauty, Health, and Sustainability; Home Improvement and Outdoors; and Media and Tech.

Dan DiClerico has written about the residential water filter market for more than 20 years, reviewing dozens of models from every leading brand. He also keeps up with the latest innovations by attending trade shows and industry events, like CES and the Kitchen & Bath Industry Show.

Nicole Papantoniou also contributed insight on the ease of use of pitchers and bottles.