Tap and Well

Reverse osmosis systems

Under-sink reverse osmosis treats one drinking-water tap. NSF/ANSI 58 is the usual standard when a unit is listed for arsenic, nitrate, or fluoride. Confirm the listing for the claim you care about.

It is not a whole-house solution. Hard water wears membranes faster. Pair with a softener if you also want scale control. Plumber recommended if you are not comfortable with a drain saddle and a tank.

12 products with an in-stock listing, sorted by first-year cost. Ranked for a named water profile only on system and ZIP pages.

Affiliate listings These are paid Amazon links. As an Amazon Associate, Tap and Well earns a commission from qualifying purchases if you buy. Rankings come from the matching engine (certification, flagged contaminants, annual cost), not from who pays more. Affiliate disclosure.

ProductCertified forPriceFirst yearInstall
APEC ROES-50 Essence 5-Stage Reverse OsmosisTotal Dissolved SolidsDIY
Aquasana OptimH2O Reverse Osmosis + ClaryumArsenic, Asbestos, Benzene, Chlorine (residual), Total Coliform and 12 moreDIY
Bluevua RO100ROPOT Countertop Reverse Osmosis Systemmanufacturer-reported onlyDIY
Brondell Circle RC100 Reverse Osmosis SystemArsenic, Barium, Benzene, Cadmium, Chlorine (residual) and 13 moreDIY
Express Water RO5DX 5-Stage Reverse Osmosis System (50 GPD)manufacturer-reported onlyDIY
Frizzlife PD600-TAM3 Tankless RO with Alkaline Remineralization (600 GPD)manufacturer-reported onlyDIY
Home Master TMAFC-ERP Artesian Full Contact RO with Permeate Pumpmanufacturer-reported onlyDIY
iSpring RCC7AK 6-Stage Alkaline Reverse OsmosisTotal Dissolved SolidsDIY
SimPure T1-400 Tankless UV Reverse Osmosis System (400 GPD)manufacturer-reported onlyDIY
Waterdrop G2P600 Tankless Reverse Osmosis System (600 GPD)manufacturer-reported onlyDIY
Waterdrop G3P600 Tankless Reverse Osmosis System (600 GPD)Cadmium, Chlorine (residual), Chromium (total), Fluoride, Selenium and 1 moreDIY
Waterdrop G3P800 Tankless Reverse Osmosis with UVPFOA, PFOS, Total Dissolved SolidsDIY