Reverse osmosis on the countertop with no plumbing. Certified by IAPMO to NSF/ANSI 42, 53, 58, 401 and 372 for every one of the 83 contaminants it claims to reduce — including PFAS, lead and microplastics. Read more in our water filter guide.

Countertop four-stage reverse osmosis with no plumbing, which AquaTru states is tested and certified by IAPMO to NSF standards to reduce 84 contaminants including lead, chromium 6, PFAS and microplastics.
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Avoid buying a countertop reverse osmosis unit for a kitchen that has no room for it. This is a real appliance with two tanks and a footprint, and it is the reason people return countertop RO. Measure the space and check for an outlet first; if neither exists, an under-sink system hides the same technology in the cabinet.
Straight answer: we're a research team, not a testing lab. Here's exactly what our rating is based on — and what it isn't — so you can weigh it honestly.
Anything that adds a known microplastic, PFAS, or off-gassing source — a non-stick coating, a plastic surface against food or skin, vinyl/PVC — is downgraded or cut. We only list what clears that bar.
Reverse osmosis on the countertop with no plumbing. Certified by IAPMO to NSF/ANSI 42, 53, 58, 401 and 372 for every one of the 83 contaminants it claims to reduce — including PFAS, lead and microplastics. Read more in our water filter guide.
Tankless under-sink reverse osmosis that Waterdrop states is certified to NSF/ANSI 42, 58 and 372, with an 0.0001 micron membrane, a three-to-one pure-to-drain ratio and minerals added back after filtering.
Five-stage under-sink reverse osmosis system carrying the Water Quality Association Gold Seal, rated at 50 gallons a day — the value entry into real RO filtration.
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