Best Reverse Osmosis Water Filters of 2026

Reverse osmosis is a slow, multistage water purification process in which household tap water is forced through specialized cartridges and a semipermeable membrane under high pressure. This enables the removal of a wide range of contaminants down to microscopic levels.

RO units typically feature a sediment prefilter that traps larger particles like sand and dirt; carbon filters that absorb bad tastes, odors, and some chemicals; and a semipermeable membrane whose microscopic pores separate pure water (“permeate”) from dissolved salts and metals and contaminated water (“concentrate”) that’s flushed down the drain. Many also have an under-sink pressurized storage tank that holds purified water until it’s ready for dispensing. A polishing filter gives the purified water a final cleanse as it’s dispensed, eliminating stale tastes and odors.

Whole-house RO systems are installed on your home’s main water supply line to purify water that goes to all faucets, showers, and appliances. Point-of-use RO systems are attached to a single fixture inside the home, usually under a kitchen sink, and many have a tank that holds the purified water. They typically dispense this filtered water through a dedicated faucet that comes with the unit, although some, like the Multipure Watts model in our ratings, require a separate purchase. 

Tankless RO systems purify tap water using an internal booster pump, dispensing water without storing it in a pressurized tank. We tested one tankless system, the Waterdrop. Others are countertop units that use a manually filled reservoir to fill a carafe, similar to a coffee maker. Countertop ROs typically plug into an electrical outlet and don’t require plumbing modifications or an under-sink water storage tank. CR hasn’t yet tested countertop RO filters.

In recent years, reports of serious water contamination in Flint, Mich., Mississippi, and other places have led more people in the U.S. to reconsider the safety of their drinking water. But the best way to know whether you’ll benefit from the cost and maintenance of a reverse-osmosis system is to find out what contaminants, if any, are present in your tap water.

You can do that by requesting a Consumer Confidence Report from your water supplier, which identifies the presence of regulated substances in the water supplied to your home. If you use well water, have it tested by an EPA-certified lab, such as SimpleLab or WaterCheck from National Testing Laboratories. Then choose a filter that’s certified by an independent organization, such as the National Sanitation Foundation, the Water Quality Association, or the International Association of Plumbing & Mechanical Officials for the removal of those specific contaminants. 

“I’d advise consumers to get their water tested and choose a filter based on the results of that analysis,” says Joan Muratore, the test engineer who oversees CR’s reverse osmosis water filter testing.

CR tested four point-of-use RO filters, and all were solid performers. Their prices range from $350 to $2,200, but you can expect to pay hundreds of dollars more annually for filter replacements. Our ratings include an annual filter replacement cost and a column listing specific cartridge model numbers. The last “filter cost” column reflects the cost of individual cartridges, including optional cartridges that remove more serious contaminants. Because some cartridges last longer than others, annual costs vary.

We verified that all four of the RO filters we tested are certified to remove lead, and the top three also remove chlorine. The two top-rated RO filters, listed below, are certified to remove lead, chlorine, PFAS, and other potentially harmful contaminants.

In addition to RO filters, we also test water-filter pitchers and faucet-mounted, under-sink, and countertop water filters. CR members can access those test results in our comprehensive water filter ratings, and both members and non-members can learn more about different types of water filters in our water filter buying guide.

Testing reverse osmosis water filters is a monthslong process during which we run the RO units continuously (24 hours a day, 7 days a week), allowing both filtered water and wastewater to flow throughout the trial. A calibrated meter tracks total water entering the system. All units are tested using CR’s well water supply, which is naturally very hard and provides a realistic and demanding source for evaluating filter performance under mineral-heavy conditions, Muratore says.

At 50-gallon intervals, we record the flow rates of both wastewater and filtered water during the 800-gallon run. To calculate efficiency, we divide the number of gallons of filtered water by the number of gallons entering the system. 

“This lets us monitor two key indicators of filter health: whether flow rates declined over time, a sign that filters were beginning to clog, and how the ratio of wastewater to filtered water shifted as the system aged,” Muratore says. “Tracking this ratio is particularly important because a rising proportion of wastewater relative to filtered water signals declining efficiency, meaning the unit uses more input water to produce the same amount of drinkable output.”

Test results for flow rate, efficiency, and likelihood of clogging are listed in our ratings. We verify whether the filter claims certification for reducing chlorine, lead, and PFAS. We also list model numbers and estimated pricing for various cartridges.