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Best Reverse Osmosis Systems - NSF Certified

Water Filter Review Process

This review article discusses the different types of reverse osmosis water filters used for common contaminants in your water.

Our primary goal is to answer one question: does the filter do what it says it will do?

To answer this question, we look for three specific criteria:

   1. Number of contaminants the filter claims to remove

   2. Quantity and quality of 3rd party certifications verifying contaminant reduction claims

   3. Supporting testing data that verifies contaminant reduction rates

These three criteria are essential in determining if you are purchasing a high-quality filter.

Filters we recommend have the highest level of certifications to back up their claims and are either directly certified by NSF or they are certified to NSF standards by a reputable 3rd party organization such as the Water Quality Association (WQA) or the International Association of Plumbing and Mechanical Officials (IAPMO)

Our Top Picks

Key Features

The Aquasana SmartFlow is NSF Certified to remove/reduce 90 total contaminants. The filter includes 4 stages – activated carbon, reverse osmosis, activated carbon, and a remineralizer for maximum removal efficiency. The remineralizer section helps increase the acidic pH commonly produced by RO water and increases the mineral and alkalinity levels.

This filter is certified by WQA to NSF standards to remove or reduce the following contaminants. For more details on removal rates see the Performance Data Sheet.

Chlorine, Mercury, Lead, MTBE, Arsenic Pentavalent, Barium, Cadmium, Chromium, Copper, Fluoride, Nitrate/Nitrite, Radium, Selenium, TDS, Turbidity, Atenolol, Bisphenol, Carbamazepine, DEET, Estrone, Ibuprofen, Linuron, Meprobamate, Metolachlor, Naproxen, Nonyl phenol, Phenytoin, TCEP, TCPP, Trimethoprim, Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS), Organic chemicals, VOCs, alachlor, atrazine, benzene, carbofuran, carbon tetrachloride, chlorobenzene, chloropicrin, 2,4-D, dibromochloropropane (DBCP), o-dichlorobenzene, p-dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,2-dichloropropane, cis-1,3-dichloropropylene, dinoseb, endrin, ethylbenzene, ethylene dibromide (EDB), haloacetonitriles (HAN), Bromochloroacetontrile, Dibromoacetontrile, Dichloroacetontrile, Trichloroacetontrile, haloketones (HK), 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone, heptachlor (H-34, Heptox), heptachlor epoxide, hexachlorobutadiene, hexachlorocyclopentadiene, lindane, methoxychlor, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-TP (silvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, Trihalomethanes (THMs), Bromodichloromethane, Bromoform, Chloroform, Chlorodibromomethane, Xylenes

This filter was tested and certified by WQA to NSF/ANSI Standards 42, 53, P473, 58 and 401 for the claims specified on the Performance Data Sheet.

NSF/ANSI 42 – Reduction of aesthetic contaminant concerns such as chlorine, taste and odor, and chloramine.

NSF/ANSI 53 – Over 50 health-related contaminant reduction claims. 

NSF/ANSI 401 – Removal of 15 specific contaminants related to prescription drugs, over-the-counter medications, herbicides, pesticides and chemical compounds.

NSF/ANSI P473 – Remove per- and polyfluoroalkyl substances (PFAS) from drinking water.

NSF/ANSI 58 – Reverse osmosis (RO) water treatment systems that remove a wide range of contaminants

The Carbon Filters will last for 365 gallons or up to 6 months. The RO membranes and remineralizer will each last for 12 months.

Pros

  • Remineralizer increases mineral content, pH, and alkalinity. This has desirable taste and health effects as it makes the water less acidic and returns the water to its normal buffering capacity
  • Wastes less water than most under sink options at a 1:3 ratio
  • Has official NSF Certifications that verify it’s performance
  • Dual Activated Carbon filter results in high removal rates

Cons

  • Requires some DIY Plumbing and cabinet space to store filters and tank
  • Reverse Osmosis has to be replaced once/year, short compared to others on the market
AquaTru Classic Countertop Water Filtration Purification System for PFAS & Other Contaminants with Exclusive Ultra Reverse Osmosis Technology (No Installation Required) | BPA Free (AquaTru Classic)

Key Features

More 3rd party certifications than any other counter top or tankless unit by far. This filter is certified by IAPMO against NSF standards 42, 53, 58. 401, and P473. Very low waste flow at only 25%.

This filter is certified by IAPMO to remove or reduce the following contaminants. For more details on removal rates, see the Performance Data Sheet.

Mercury, Lead, Arsenic, Barium, Cadmium, Chromium, Copper, Fluoride, Nitrate, Nitrite, Selenium, TDS, Turbidity, Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS), Organic chemicals, VOCs, alachlor, atrazine, benzene, carbofuran, carbon tetrachloride, chlorobenzene, chloropicrin, 2,4-D, dibromochloropropane (DBCP), o-dichlorobenzene, p-dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,2-dichloropropane, cis-1,3-dichloropropylene, dinoseb, endrin, ethylbenzene, ethylene dibromide (EDB), Bromochloroacetontrile, Dibromoacetontrile, Dichloroacetontrile, Trichloroacetontrile, 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone, heptachlor (H-34, Heptox), heptachlor epoxide, hexachlorobutadiene, hexachlorocyclopentadiene, lindane, methoxychlor, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-TP (silvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, Trihalomethanes (THMs), Bromodichloromethane, Bromoform, Chloroform, Chlorodibromomethane, Xylenes, cyst, perchlorate, radium, selenium, chloramine, chlorine, meprobamate, phenytoin, atenolol, carbamazepine, TCEP, TCPP, DEET, Metolachlor, trimethoprim, ibuprofen, naproxen, estrone, bisphenol A, linuron, nonyl phenol 

This filter is certified by IAPMO against NSF standards 42, 53, 58, 401, and P473 for claims specified on the Performance Data Sheet.

NSF/ANSI 42 – Reduction of aesthetic contaminant concerns such as chlorine, taste and odor, and chloramine.

NSF/ANSI 53 – Over 50 health-related contaminant reduction claims. 

NSF/ANSI 401 – Removal of 15 specific contaminants related to prescription drugs, over-the-counter medications, herbicides, pesticides, and chemical compounds.

NSF/ANSI P473 – Remove per- and polyfluoroalkyl substances (PFAS) from drinking water.

NSF/ANSI 58 – Reverse osmosis (RO) water treatment systems that remove a wide range of contaminants

Pre/Carbon Filter Part replace every 6 months or 600 gallons.
Reverse Osmosis Membrane Part replace every 24 months or 1200 gallons.
VOC filter Part replace every 12 months or 600 gallons.
VOC Carbon with PH+Mineral Boost filter replace every 12 months or 600 gallons.

Pros

  • The most 3rd party certifications for contaminant removal than any other RO system that is not under-sink
  • Can be purchased in 3 separate models that include remineralizer and/or smart features such as filter life and water usage
  • No plumbing or installation is required, very easy to setup
  • 4 filter stages, including 2 carbon filters in addition to reverse osmosis for maximum removal rates
  • Only Wastes 25% of water. The standard waste rate for most reverse osmosis systems is 75%

Cons

  • Not directly certified by NSF
  • Small storage tank that requires being manually emptied and filled
  • Stagnant water can lead to bacteria growth if the water chamber is not used and cleaned often
Waterdrop G3 Reverse Osmosis System, 8 Stage Tankless Reverse Osmosis Water Filter, NSF/ANSI 42 & 58 & 372 Certified, Under Sink RO System, 2:1 Pure to Drain, Smart LED Faucet

Key Features

Certified by IAPMO against NSF/ANSI standard 58. The only tankless RO that has 3rd party certifications and a contaminant specification sheet detailing removal rates. Available in 600 and 800 gallon/day models.

This filter is certified by IAPMO to NSF/ANSI 58 for TDS reduction. This filter is also independently tested to reduce the below contaminants. For more details on removal rates see thPerformance Data Sheet.

Mercury, Lead, Arsenic, Barium, Cadmium, Chromium, Copper, Fluoride, Nitrate, Selenium, TDS, Turbidity, Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS), Organic chemicals, VOCs, alachlor, atrazine, benzene, carbofuran, carbon tetrachloride, chlorobenzene, chloropicrin, 2,4-D, dibromochloropropane (DBCP), o-dichlorobenzene, p-dichlorobenzene, 1,2-dichloroethane, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,2-dichloropropane, cis-1,3-dichloropropylene, dinoseb, endrin, ethylbenzene, ethylene dibromide (EDB), Bromochloroacetontrile, Dibromoacetontrile, Dichloroacetontrile, Trichloroacetontrile, 1,1-dichloro-2-propanone, 1,1,1-trichloro-2-propanone, heptachlor (H-34, Heptox), heptachlor epoxide,  hexachlorobutadiene, hexachlorocyclopentadiene, lindane, methoxychlor, pentachlorophenol, simazine, styrene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, toluene, 2,4,5-TP (silvex), tribromoacetic acid, 1,2,4-trichlorobenzene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, trichloroethylene, Trihalomethanes (THMs), Bromodichloromethane, Bromoform, Chloroform, Chlorodibromomethane, Xylenes

This filter was tested and certified by IAPMO to NSF/ANSI Standards 42, 53, and 58 for the claims specified on the Performance Data Sheet.

NSF/ANSI 42 – Reduction of aesthetic contaminant concerns such as chlorine, taste and odor, and chloramine.

NSF/ANSI 53 – Over 50 health-related contaminant reduction claims.

NSF/ANSI 58 – Reverse osmosis (RO) water treatment systems that remove a wide range of contaminants.

Smart faucet and filter life indicators that notify you when the filter needs to be changed out. The pre-filter has a 6 month lifetime. The carbon block has a 1 year lifetime. The RO has a 2-year lifetime. Model is available in 600 and 800 gallon/day flow.

Pros

  • RO System has a low drain ratio of 2:1, which means it only wastes 33% of the water flowing in
  • Smart Display that shows TDS levels, this is an excellent way to tell if your filter needs to be changed soon
  • No tank, much lower footprint than traditional under-sink options
  • Includes scale prevention media that helps protect RO membranes in areas with high hardness.
  • Upgradeable to a higher flow rate of 800 gallons/day which includes UV filtration for biological treatment. Ideal for those using well water.

Cons

  • Expensive
  • Only truly certified by NSF 58 reduction claim for TDS, rest of claims are independently tested.
  • Remineralizer sold separately
  • Requires some DIY plumbing to setup
  • Claims to reduce limescale by 95%, we have not found any independent testing to verify.
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