6 Best Countertop Reverse Osmosis Systems (*Update 2024)

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Top Pick: What’s the Best Countertop Reverse Osmosis System?

The best countertop reverse osmosis system in 2024 is the AquaTru, that’s because it is NSF-certified to remove 80+ water contaminants, installation-free, fast, water-saving, easy and affordable to maintain, and it has a long filter life of up to 1,200 gallons.

Finding the perfect countertop reverse osmosis system for your needs can be a daunting task, considering the multitude of good and bad options available.

That’s why our team has invested countless hours in researching and reviewing over 26 of the leading countertop RO systems since our buying guide’s initial publication on August 24, 2018.

Through rigorous evaluation, testing, comparison, and ranking of these products, as well as continuous updates and edits to our guide, our aim is to provide you with the necessary information to make an informed purchasing decision.

Video Update: 10 Countertop Reverse Osmosis Systems Lab-Tested + Reviewed

Sara, one of our inhouse video content creators, has reviewed 10 of the most popular and most promising countertop reverse osmosis systems. This included lab testing for contaminant reduction for all 10 systems! The recommendations we give in this video are the most up-to-date and reflect our current opinion.

Here is how we tested and ranked the 10 countertop ROs:

  • Filtration effectiveness based on real-life contaminant reduction rates achieved in our lab testing
  • NSF certifications and NSF testing
  • Filter process
  • Filtered water taste and odor
  • Usability
  • Pure-to-drain ratio
  • Upfront price and long-term cost for replacement filters
  • Other factors

The Google Sheet mentioned in the video with our full analysis of each of the 10 countertop ROs including lab reports can be found here: https://docs.google.com/spreadsheets/d/1svUVI186tOTNQmvrfTPGTYDmBnB1BX5szhASozXf0KU/edit

Product Links & Discount Codes

1. Best Overall: AquaTru Classic

2. Best Budget Pick: AquaTru Carafe

3. Best for Hot Water: NU Aqua 4-Stage Countertop Reverse Osmosis System and APEC ROCT-PLUS

4. Honorable Mention: Bluevua RO100ROPOT

Other Countertop Reverse Osmosis Systems Reviewed in This Video

No Time to Read? Check Our List of the Best Countertop Reverse Osmosis Systems!

Products Details
AquaTru 4-Stage Compact Countertop Reverse Osmosis System
Best Overall: AquaTru

Overall Rating: 4.5/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 15% Off! Use Code: BOSAQUATRU

Price: $$$
Filter Stages: 4
Filtered Water: 1 Gallon in 10-15 Minutes
NSF Standards: 42, 53, 58, 401, P473
Annual Cost: ~$100-120
Read Review: Click
Alexa’s Video Review: Click
Sara’s Video Review: Click
SimPure Y7P-BW Countertop Reverse Osmosis System
The Runner-Up: SimPure Y7P-BW

Overall Rating: 4.5/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 20% Off! Use Code: SPY7P

Price: $$
Filter Stages: 4
Filtered Water: Not Specified
NSF Standards: 58
Annual Cost: ~$120
Read Review: Click
Alexa’s Video Review: Click
Compact & Portable RO System: Crystal Quest Thunder
Best Portable System: Crystal Quest Thunder

Overall Rating: 4.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 5% Off! Use Code: BOS5OFF

Price: $$
Filter Stages: 10
Filtered Water: 0.03 Gallons Per Minute
NSF Certified:
Annual Cost: ~$65-100
Read Review: Click
Waterdrop G3P600 Reverse Osmosis System
Best for Tankless Purification: Waterdrop G3

Overall Rating: 4.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 10% Off! Use Code: WD10BOS

Price: $$$
Filter Stages: 4
Filtered Water: 1 Gallon in 2-3 Minutes
NSF Standards: 58, 372
Annual Cost: ~$145
Read Review: Click
Alexa’s Video Review: Click

Countertop Reverse Osmosis System Reviews

Our Top Picks

  1. AquaTru Countertop Reverse Osmosis System – Best Overall
  2. SimPure Y7P-BW RO Countertop Water Filter – Runner-Up
  3. Zero Installation Purifier Countertop Reverse Osmosis System – Best for Remineralization
  4. Crystal Quest Thunder Portable Countertop Reverse Osmosis System – Best Portable
  5. Waterdrop WD-G3-W Tankless RO System – Best for Tankless Purification
  6. PuroSmart – Smallest RO System

1. Best Overall: AquaTru (Including Coupon Code!)

In our opinion, the best countertop reverse osmosis system in 2024 is the AquaTru. It’s independently tested and NSF certified against 5 standards (42, 53, 58, 401, P473) to remove up to 99.99% of 82 different water contaminants. In other words, it provides highly pure, safe, and great-tasting drinking water.

But the best thing about the AquaTru countertop RO system is that it’s a plug & play model that doesn’t require any kind of installation/plumbing – ideal for renters and to save money. On top of that, maintenance is a breeze and super low-cost. 4.5 stars!

AquaTru 4-Stage for table or countertop

AquaTru

Price: $$$
Stages: 4
Purified Water: 1 Gallon in 10-15 Minutes
NSF Certifications: 42, 53, 58, 401, P473
Annual Cost: ~$100-120

Overall Rating: 4.5/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 15% Off! Use Code: BOSAQUATRU

Alexa’s Video Review

Alexa, our inhouse video content producer, has ordered and tested the AquaTru Reverse Osmosis System. In other words, she set up the AquaTru with her own hands and used it in her home for several weeks to gain invaluable first-hand experience and insights. Alexa has documented the entire process and shares her opinion on the water filter in the video below:

AquaTru Reverse Osmosis Water Filter Image 1AquaTru Reverse Osmosis Water Filter Image 4AquaTru Reverse Osmosis Water Filter Image 3AquaTru Reverse Osmosis Water Filter Image 2

The 3-part filtration system is quite impressive. It really removes everything out of the water. As far as water filtration systems go this will be a very high quality option for you. (…) Overall my review of this system is going to be a 4.5 out of 5.

Alexa Gibbons – BOS Video Content Creator

Alexa

Sara’s Video Review

Sara has also tested the AquaTru. And here review even includes lab testing, so a comparison of the unfiltered vs. filtered water:

The AquaTru Reverse Osmosis Countertop System has a very effective filtration process backed by NSF certifications, it has very little wastewater, it is an installation-free system and it is very easy to use, and the maintenance is pretty affordable.

Sara Radle – BOS Video Content Creator

Sara

Other Specs

  • Model: AquaTru
  • Last Price: $449.00
  • Filter Process: Sediment/Carbon, RO, Carbon Block
  • Recovery Rate: 80%
  • Filtering Capacity: 600-1,200 Gallons
  • WxHxD: 12″x14″x14″
  • Water Temperature: 39-100 °F
  • Operating Pressure: 40-85 psi
  • Warranty: 1 Year

Key Features & Pros

  • Countertop reverse osmosis water filtration system can be set up in less than 10 minutes without plumbing or drilling for maximum convenience.
  • It’s very easy to use and space-saving.
  • NSF certification standards 42, 53, 58, 401 and protocol P473 guarantee the most effective contaminant removal for healthy and clean drinking water, e.g. chromium-6 (97.2%), cyst (99.99%), fluoride (93.5%), lead (99.1%), chlorine (96.6%), Ibuprofen (95.1%), Bisphenol A (99.0%), PFOA & PFOS (97.5%), VOCs (most >99%).
  • 4 stage filtration process:
    • Stage 1 + 2: Mechanical + activated coconut shell carbon pre-filter traps sediment like dust and other large particles, and adsorbs chemicals and bad taste & odor among other things.
    • Stage 3: RO membrane rejects impurities like fluoride, heavy metals, and overall TDS.
    • Stage 4: Activated coconut shell carbon block post-filter eliminates residual taste, pesticides, organic compounds, …
  • Fast filtration purifies a full gallon of water in 10 to 15 minutes, so no long waiting times.
  • A pressure pump increases water productivity and lowers reject water percentage.
    • 80% recovery rate means only 20% of water goes down the drain as wastewater (other reverse osmosis systems without a pump waste as much as 3-5 gallons of water for every gallon filtered).
  • Clean water can be dispensed via button push. Tank is portable and can be stored in refrigerator for cooling.
  • Wastewater collects in another tank and can be discarded.
  • Material is BPA and BPS-free Tritan plastic.
  • High-capacity filters last 600 gallons of water (6-12 months capacity) and reverse osmosis membrane lasts a full 1,200 gallons (2 years) for lowest maintenance requirements.
    • Cost are surprisingly affordable: About $100-120 per year.
  • Maintenance is straightforward thanks to tool-free replacement process. An indicator light tells you when you need to change the filters and RO membrane.
    • Takes barely 2 minutes.
  • The AquaTru countertop reverse osmosis water filter system is warranted for 1 year.

Cons

  • Potential leaking due to design flaw.
  • Some reviewers said their unit malfunctioned after a while.

Our Rating

  • Filtration Performance: 4.5/5.0
  • Filter Life: 5.0/5.0
  • Price: 4.0/5.0
  • Annual Filter Replacement Cost: 5.0/5.0
  • Overall: 4.5/5.0

Best for

The AquaTru is best for people who want a countertop reverse osmosis system that’s compact, installation-free, easy to use, very effective, and fast.

→ Read Our Full Review of the AquaTru Here

2. The Runner-Up: SimPure Y7P-BW Reverse Osmosis Countertop Water Filter

Our second most favorite countertop reverse osmosis system is the SimPure Y7P-BW. It’s arguably the best looking unit that is part of this guide, which isn’t to be neglected when talking about RO systems designed for countertops.

Besides, the SimPure Y7P-BW is installation-free, it features built-in UV disinfection, and thanks to its circular multi-filtration process, it has one of the best pure-to-drain-water ratios (4:1). Comprehensive NSF 58 testing is the cherry on top. Highly recommended!

SimPure Y7P-BW Countertop Reverse Osmosis System

SimPure Y7P-BW Reverse Osmosis Countertop Water Filter

Price: $$
Stages: 4
Purified Water: Not Specified
NSF Testing: 58
Annual Cost: $120

Overall Rating: 4.5/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 20% Off! Use Code: SPY7P

Alexa’s Video Review

Alexa is one of our inhouse video content producers, and she has ordered and tested the SimPure Y7P-BW Reverse Osmosis System for us. In other words, she set up the system with her own hands and used it in her home for several weeks to gain invaluable first-hand experience and insights. She even sent an unfiltered and a filtered water sample to a lab for direct comparison. Alexa has documented the entire process and shares her opinion on the SimPure Y7P-BW in the video below:

Simpure Y7P-BW Countertop Reverse Osmosis System Image 1Simpure Y7P-BW Countertop Reverse Osmosis System Image 2Simpure Y7P-BW Countertop Reverse Osmosis System Image 3Simpure Y7P-BW Countertop Reverse Osmosis System Image 4

Installation was an A+. And then of course the biggest pro is just that the water tastes good. (…) My husband enjoyed using this in his office. He liked the sleek design (…). He liked being able to just put his cup under it and press the button. (…) I’m gonna give this water filter a 4 out of 5.

Alexa Gibbons – BOS Video Content Creator

Alexa

Other Specs

  • Model: Y7P-BW
  • Last Price: $369.99
  • Filter Process: Sediment/Carbon Block, RO, UV
  • Membrane Rating: 100 gpd
  • Recovery Rate: 80%
  • Filtering Capacity: 528 gal
  • WxHxD: 8″x17″x18″
  • Warranty: 1 Year

Key Features & Pros

  • Compact and stylish design makes the Y7P-BW great for home and office use.
  • System has 3 filters:
    • Sediment and carbon composite filter catches floating particles like sand, silt, and other dirt. Plus, it reduces chlorine and other chemicals. This improves water taste and also protects the RO membrane.
    • Reverse osmosis membrane filters more than 1,000 different water impurities, most importantly lead (98.46%), arsenic (99.65%), parasites, chromium 6 (99.28%), PFOA (98.75%), PFOS (98.3%) …
    • UV post-filter eliminates any harmful microorganisms.
  • Water recycling technology lowers wastewater production. Only 1 gallon goes down the drain per 4 gallons of pure water.
    • Together with the AquaTru, this is the best ratio of all the systems directly compared.
    • Keeps your utility bill low.
  • NSF 58 testing.
  • Countertop RO system features cup size selection: Select 6 oz, 12 oz, 15 oz, or continuous flow.
  • BPA-free.
  • No installation required. Just plug it in.
  • Easy to use: Simply fill the 1.3-gallon feed water tank and wait a bit.
  • Twist-in filter system. It makes filter replacements a breeze.
    • Filter replacement alerts. No need to remember date of last filter change.
    • Sediment + carbon block pre-filter and RO membrane last 528 gallons or 6 months.
  • 1-year warranty.

Cons

  • No official NSF certifications for contaminant reduction.
  • A bit noisy when motor starts for few minutes.
  • Rather short filter life.

Our Rating

  • Filtration Performance: 4.5/5.0
  • Filter Life: 4.0/5.0
  • Price: 4.5/5.0
  • Annual Filter Replacement Cost: 5.0/5.0
  • Overall: 4.5/5.0

Best for

The SimPure Y7P-BW is best for people who care about pure-to-drain-water ratios and a stylish design of their home water filter.

→ Full SimPure Y7P-BW Review

3. Best for Remineralization: Zero Installation Purifier Countertop RO Water Filtration System – AlcaPure Edition

The Zero Installation Purifier is another standalone reverse osmosis water filter that doesn’t require installation. Overall customer feedback is positive with people being most happy about the ease of use. 4 stars!

Zero Installation Purifier RO system for table or countertop

Alkaline RO Water Filtration System: Zero Installation Purifier

Price: $$$
Stages: 4
Purified Water: 1/2 Gallon in 15-20 Minutes
NSF Certifications: 58
Annual Cost: ~$105-125

Overall Rating: 4.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 8% Off! Use Code: BOS8%OFF

Other Specs

  • Model: RKIN-ZIPAL-BLK, RKIN-ZIPAL-WHT
  • Filter Process: Sediment (5 Microns), Carbon Block, RO, Carbon + Remineralizer
  • Membrane Rating: 75 gpd
  • Recovery Rate: 55.08%
  • Filtering Capacity: 12-24 Months
  • WxHxD: 9.5″x16.25″x14.5″
  • Water Temperature: 68-78 °F
  • Warranty: 1 Year

Key Features & Pros

  • Choose between Space Black and Silver White design.
  • This countertop RO machine is installation-free which is ideal for renters and if you don’t want to modify your plumbing or hire a plumber.
  • Very easy to use. Simply fill water into the bottom tank and push start button.
  • 4 filtration stages remove up to 99% of contaminants.
  • At first, a 5-micron sediment filter removes sand, rust, and other dirt to prevent clogging of the rest of the system.
  • Filter stage 2 uses a coconut shell activated carbon filter block to adsorb chlorine, disinfection byproducts, bad taste and odor, chemicals, etc.
    • Optional: Use the anti-scale carbon pre-filter if your water is very hard or high in TDS. Prevents scaling of the other stages for longer filter life span.
  • Filter stage 3: The reverse osmosis membrane removes heavy metals and other pollutants.
  • Filter stage 4 combines a carbon post-filter with remineralization.
    • Gives water a final polish removing residual contaminants.
    • Enriches water with healthy calcium and magnesium. Improves taste + balances pH (alkalinity).
  • NSF Standard 58 certification for the reduction of TDS, lead, chromium 6, fluoride, and PFOA/PFOS.
  • Pressure pump boosts filtration speed and improves recovery rate to 55%.
    • It takes 15-20 minutes to process a gallon of water.
    • Only one gallon of water is wasted for every gallon of clean water (average reverse osmosis water filter system wastes 3-5 gallons).
  • Water tanks are BPA-free.
  • Maintaining the countertop unit doesn’t require much time or effort. A warning light reminds you to replace filters once a year. Long-lasting reverse osmosis membrane has a capacity of about 2 years.
    • Sediment filter and carbon pre-filter feature twist on/off mechanism. The other filter stages use quick-connect fittings.
    • Cost: About $105 to $125 per year which is hard to beat.
  • 1-year money-back satisfaction guarantee for peace of mind (only when bought on purewaterguys.com).
  • Covered by 1-year warranty (limited).

Cons

  • It can be difficult to lock the feed tank in place so that the purification process won’t start or may cause leaking.
  • Some reviewers said their unit quit working entirely as it wouldn’t detect the feed water tank anymore.
  • Leaking from different parts of the system.
  • Some parts don’t feel very sturdy.

Our Rating

  • Filtration Performance: 4.0/5.0
  • Filter Life: 5.0/5.0
  • Price: 4.0/5.0
  • Annual Filter Replacement Cost: 5.0/5.0
  • Overall: 4.0/5.0

Best for

The ZIP is best for people who want RO-purified, remineralized drinking water.

→ Read Our Detailed Zero Installation Purifier Review

4. Best Portable System: Crystal Quest Thunder

In our opinion, the best portable reverse osmosis system in 2024 is the Crystal Quest Thunder. It’s not the only countertop model that’s installation-free but it’s probably the one with the highest portability. Plus, it doesn’t require electricity so it can be a great reverse osmosis water filter system for camping if you have access to a standard-sized faucet. 4 stars!

Please note: The Crystal Quest Thunder misses NSF certifications with specific contaminant reduction rates which is why we prefer the AquaTru when portability is not a must!

Crystal Quest - Portable Countertop Reverse Osmosis System

Crystal Quest Thunder

Price: $$
Stages: 10
Purified Water: 0.03 Gallons Per Minute
NSF Certifications:
Annual Cost: ~$65-100

Overall Rating: 4.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 5% Off! Use Code: BOS5OFF

Other Specs

  • Model: CQE-CT-00142
  • Last Price: $202.23
  • Filter Process: GAC, RO, KDF, Ion Exchange, 1-Micron Filter Pads
  • Membrane Rating: 50 gpd
  • Filtering Capacity: 1-3 Years
  • WxHxD: 16″x7″x7″
  • Water Temperature: 40-85 °F
  • Operating Pressure: 45 psi Minimum
  • Warranty: 1 Year

Key Features & Pros

  • Made in the USA.
  • The Crystal Quest Thunder portable 10-stage countertop reverse osmosis water filter system is easy to install in no time – all hardware included.
  • Measuring 16x7x7 inches, it’s very compact and might even fit in your trunk when travelling – size is similar to the APEC Water Systems RO-CTOP (a.k.a. APEC RO-CTOP).
  • Produces great-tasting water.
  • Uses granular activated carbon (stage 2) to trap chlorine, pesticides, VOCs, bad tastes and odor, and more.
  • Uses RO membrane (stage 4) to reject most organic and inorganic contaminants.
  • Uses copper-zinc oxidation media (Eagle Redox Alloy, stage 6 + 7) to primarily reduce water-soluble heavy metals such as lead, arsenic, and chromium. The blend also prevents bacterial growth inside the system.
  • Uses ion exchange resin (stage 8) to lower heavy metal content even further and also addresses water hardness.
  • Uses granular carbon post-filter (stage 9) to eliminate residual tastes.
  • A 1-micron filter pad before and after each filter stage blocks suspended solids and cyst.
  • Additional filter cartridges can be added to the countertop RO system.
  • The high-capacity filters keeps maintenance at a minimum.
    • Replacement is fast and easy thanks to quick-connect fittings.
    • Cost: $65-100 per year, so not much!
  • Customer service is great.
  • 1-year warranty.
  • Reasonable price.

Cons

  • No data on performance or NSF certifications is provided.
    • Not that important with reverse osmosis systems unless you want to remove one or more specific contaminants.
  • Production is around 2 gallons of purified water per hour so the system is probably best used in combination with a large container to eliminate long waiting times.
  • Fits standard-sized faucets only.

Our Rating

  • Filtration Performance: 4.0/5.0
  • Filter Life: 5.0/5.0
  • Price: 4.5/5.0
  • Annual Filter Replacement Cost: 5.0/5.0
  • Overall: 4.0/5.0

Best for

The Thunder is best for people who want a highly portable reverse osmosis system.

→ Read Our Full Crystal Quest Thunder Review Here

5. Best for Tankless Reverse Osmosis Water Treatment: Waterdrop G3 System

Our #1 tankless reverse osmosis system in 2024 is the Waterdrop G3. Sleek design, straightforward install, effortless filter replacements, and great water taste – people love this water filter which is not a countertop but an under sink unit. 4 stars!

Waterdrop G3P600 Reverse Osmosis Water Filtration System

Waterdrop G3 Tankless RO System

Price: $$$
Stages: 4
Purified Water: 0.42 Gallons Per Minute
NSF Certifications: 58, 372
Annual Cost: ~$145

Overall Rating: 4.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Get 10% Off! Use Code: WD10BOS

Alexa’s Video Review

Being part of the BOS team, Alexa has ordered and tested the Waterdrop G3 Reverse Osmosis System, which means she has installed the system with her own hands and used it for several weeks for some genuine first-hand experience! Alexa has documented the entire process, including her findings and personal verdict, in the video provided below:

Waterdrop G3 Reverse Osmosis Water Filter System Image 1Waterdrop G3 Reverse Osmosis Water Filter System Image 4Waterdrop G3 Reverse Osmosis Water Filter System Image 2Waterdrop G3 Reverse Osmosis Water Filter System Image 3

My overall rating for this water filter is going to be a 3.5 out of 5. I hate to give it below of a 4, because I think that this is a great filter (…). I just had a very difficult time setting it up (…). If you have someone else do this who is very good at plumbing then you won’t even have to worry about that.

Alexa Gibbons – BOS Video Content Creator

Alexa

Other Specs

  • Model: G3P600
  • Last Price: $539.00
  • Filter Process: Sediment, 2x Carbon Block, RO Membrane
  • Membrane Rating: 600 gpd
  • Recovery Rate: 66%
  • Filtering Capacity: 550-2,200 Gallons
  • WxHxD: 5.67″x17.72″x18.12″
  • Water Temperature: 41-100 °F
  • Operating Pressure: 14.5-87 psi
  • Warranty: 1 Year

Key Features & Pros

  • Tankless design saves a lot of space.
  • Internal pump increases pressure for 0.42 gallons per minute clean water flow.
    • One cup of water fills in about 8 seconds. No long waiting times!
    • Higher pressure also lowers the amount of waste water going down the drain to two-third of a gallon for every gallon of filtered water.
  • Stage 1: Composite filter (polypropylene cotton + coconut shell activated carbon block) eliminates chlorine and large solids (sediment).
  • Stage 2: 0.0001-micron reverse osmosis membrane rejects heavy metals, bacteria among other microorganisms, fluoride, and common contaminants such as arsenic.
  • Stage 3: Another activated carbon block filter removes residual chemicals and tastes.
  • System was designed for easy installation to save money.
    • Make sure to follow the provided instructions and helpful explainer videos found on YouTube.
  • All plastic is BPA-free to prevent contamination of the water.
  • Smart faucet uses built-in LED light to indicate filter status so no need to remember when to replace. White: Everything is good. Yellow: Less than 40 gallons or 15 days filtration capacity remaining. Red: Filter change required immediately.
    • Same indicator can be found on the system’s front panel.
    • TDS monitor also tells you about the condition of the filter elements.
  • Filters can be changed with a simple twist, no need for tools. Takes less than 10 seconds. Cost: About $145 per year.
  • 30 days satisfaction guarantee.
  • 1-year manufacturer warranty (only when countertop water filter is used with tap water).

Cons

  • Only NSF certification proving filtration effectiveness is Standard 58 for total dissolved solids. We would have preferred more thorough testing.
  • Some people have to drain about one gallon of water before the system reads TDS <30 ppm. We assume this to be TDS creep.

Our Rating

  • Filtration Performance: 4.0/5.0
  • Filter Life: 5.0/5.0
  • Price: 3.5/5.0
  • Annual Filter Replacement Cost: 4.5/5.0
  • Overall: 4.0/5.0

Best for

The Waterdrop G3 is best for people who want a tankless RO system that doesn’t occupy much space and that’s quick to install, easy to use, and fast.

→ Read Our Full Waterdrop Reverse Osmosis Review Here

6. Smallest RO System: PuroSmart

Still haven’t found the ideal countertop reverse osmosis filter for your needs? Maybe you are looking for something a bit more tiny…

The PuroSmart is probably the smallest RO system of all. You might find it useful if the number one thing you lack in your home or kitchen is space, or if you’re constantly on the move and want a basic water purification system wherever you go.

Not small but mini: PuroSmart

Smallest Reverse Osmosis Water Filter System: PuroSmart

Price: $
Stages: 2
Filtered Water: Up to 50 Gallons a Day
NSF Certifications:
Annual Cost: ~$80

Overall Rating: 3.0/5.0 ⓘRatings based on effectiveness of filtration, filter life, cost, NSF/ANSI standards, our testing, 3rd party user ratings, product support, warranty, and other factors.

Other Specs

  • Model: ‎PSFM50, PSCT50
  • Filter Process: Carbon Block, RO
  • Membrane Rating: 50 gpd
  • Filtering Capacity: 3-12 Months
  • Height: 8.25″
  • Warranty: 1 Year

Key Features & Pros

  • The PuroSmart is easily the most compact countertop reverse osmosis water filter system we’ve ever seen. Length: 8.25 inches.
  • It’s convenient to use and there’s no permanent installation required. Simply replace your kitchen faucet aerator with the diverter valve included in the package. Then mount the unit on the plastic stand and make the tubing connections. From now on you can enjoy clean and refreshing reverse osmosis drinking water straight from the tap!
  • A mini carbon block pre-filter removes chlorine. Capacity: 400 gallons or 3 months filter life.
  • The RO membrane does its thing reducing TDS.
  • Produces up to 50 gallons of purified water per day at 60 psi feed pressure, according to manufacturer.
  • Comes with a limited warranty (one year).

Cons

  • We wouldn’t rely on this reverse osmosis water filtration system to produce water 100 percent safe for consumption.
  • The PuroSmart is more expensive that you’d think, both at initial purchase and when replacing the filter elements. Annual cost: About $80.
  • We doubt that you’ll get 50 gallons of RO water out of this unit per day.

Our Rating

  • Filtration Performance: 3.0/5.0
  • Filter Life: 3.5/5.0
  • Price: 3.5/5.0
  • Annual Filter Replacement Cost: 3.5/5.0
  • Overall: 3.0/5.0

Best for

The PuroSmart is best if you want a reverse osmosis filter system that’s incredibly small.

Comparison List

(Mobile Hint: Swipe to Scroll)

Water Filters Price Filter Process Stages Membrane Rating Pure:Drain Ratio Water Production NSF/ANSI Filter Life Annually Warranty Additional Info
AquaTru Water Filtration/Purification System $$$ Sediment + Carbon Composite, RO, Carbon Block 4 ? 4:1 4-6 gal/h 42, 53, 58, 401, P473 600-1,200 gal ~$100-120 1 Year
SimPure Y7P-BW RO Countertop Filter System $$ Sediment + Carbon Block, RO, UV 4 100 GPD 4:1 Not Specified 58 528 gal $120 1 Year
Zero Installation Purifier Reverse Osmosis Filter $$$ Sediment (5 Microns), Carbon Block, RO, Carbon + Remineralizer 4-Stage Filtration 75 GPD 1:1 1.5-2 gal/h 58 1-2 Years ~$105-125 1 Year (Limited)
Crystal Quest Thunder RO Filter $$ Granular Activated Carbon, RO, KDF, Ion Exchange, 1-Micron Filter Pads 10-Stage Filtration 50 GPD ? 0.03 gpm 1-3 Years ~$65-100 1 Year
Waterdrop WD-G3-W Reverse Osmosis Filter $$$ Sediment + Carbon Composite, RO, Carbon Block 4-Stage Filtration 600 GPD 2:1 0.42 gpm 58, 372 550-2,200 gal ~$145 1 Year
PuroSmart RO Filter $ Carbon Block, RO 2 50 GPD ? Up to 50 Gallons of Drinking Water Per Day 3-12 Months ~$80 1 Year

Buying Guide: How to Choose the Countertop RO System That’s Best for You

The following are key features worth considering when shopping for a countertop reverse osmosis water filter. They will help you choose the right on for your needs and budget.

Faucet Connection

As a general rule, countertop water filters fit standard kitchen faucets only. Yes, there are adapters for bathroom taps and garden hoses etc., but if you are using a designer, pull-down, or sprinkler faucet that’s bad luck!

designer kitchen faucet

In any case, double-check that the faucet in question allows for a standard hose connection. If not, try to find a compatible adapter. By the way, most reverse osmosis countertop systems are shipped with a few adapters to try out.

Certificates

We like to rely on certifications according to NSF standards. They guarantee that a certain water filter model or system is capable of removing/reducing a considerable amount of potentially harmful contaminants in water in addition to those affecting aesthetics.

Searching for the best countertop reverse osmosis water filter system, you should look out for NSF Standard 42 for water aesthetics, Standard 53 for contaminants with health effects, Standard 58 for further substances, Standard 401 for emerging contaminants, and NSF Protocol P473 specifically for the reduction of PFOA and PFOS.

Some of the standards also cover a product’s material safety and structural integrity.

Water Pressure & Wastewater

Reverse osmosis water filters without a built-in pressure pump rely entirely on the water pressure in your home’s pipes to force water through their different filter stages. This has the benefit that no extra power supply is needed.

What might come in handy on a camping trip can be an issue if the water pressure in your home is too low. Because low water pressure not only results in a slow flow rate, it also increases the amount of wastewater going down the drain.

To be more precise, the filtered to drain water ratio declines: Under normal conditions and without applying a pump, reverse osmosis systems waste 2 to 4 gallons of water for every gallon that you can drink or use otherwise. In cases of extremely low pressure, this ratio can increase to 1:6 or even 1:8.

Most RO systems tend to perform best at around 65 psi. Anything less than 35 psi is considered insufficient.

Flow Rate

Simply put, RO systems producing water on demand should have a high enough flow rate to avoid long waiting times.

Maintenance (Cost)

Countertop/portable reverse osmosis water filters are low in maintenance, so no need to worry about that. What you should pay attention to, however, is maintenance cost.

While some units are more expensive to purchase, they might be cheaper to maintain, and vice versa. So don’t forget to check the cost, capacity & longevity, and availability of replacement filter elements. (Of course, that’s exactly what we did with each product reviewed above!)

Design

Do yourself a favor and don’t choose the ugliest system if it’s going to sit on the top of your counter for the next 5 to 10 years.

More on Countertop and Portable Reverse Osmosis Systems

What Is a Countertop Reverse Osmosis System?

Simply put, a countertop (counter-top) reverse osmosis system is a device for filtering water, making it ready for drinking. As the name suggests, countertop RO systems rely on reverse osmosis treatment technology to remove up to 99% water contaminants including lead, chlorine, fluoride, chromium, microorganisms, chemicals, and much more. In other words, they are highly, highly effective.

Apart from reverse osmosis filters that sit on the countertop, there’re under sink units and whole house systems.

Countertop models are either standalone or they connect to a faucet. Furthermore, we can differentiate between systems producing water on demand and those featuring a tank to store the purified water in.

Pure water flow: Anywhere between 2 to 6 gallons per hour.

How Does a Countertop RO Water Filter Work?

Countertop reverse osmosis water filtration systems are either fed through a faucet connection or they have a feed water tank that requires manual refilling. Once in the system, the water goes through several filtration stages – the specific setup varies from model to model – before it’s ready for dispensing. Here’s what a typical reverse osmosis process looks like:

  1. The first filter stage is usually a sediment pre-filter. It protects the rest of the system from clogging.
  2. Next comes an activated carbon filter, either granular or block. The carbon adsorbs chlorine, bad taste and odor, VOCs as well as other chemicals, and discoloration.
  3. At the heart of the countertop water filter is the reverse osmosis membrane which rejects 98-99% of all total dissolved solids. It does the bulk of the contaminant removal.
  4. A second coconut shell GAC stage filters residual tastes.
  5. Some water filtration systems make use of remineralization. It releases calcium and magnesium and possibly other minerals into the water which improves overall water quality.

Natural Osmosis Process Diagram

Reverse Osmosis Process Diagram

Reasons to Invest in a Water Filtration System: Advantages (& Limitations)

Advantages

  • Reverse osmosis water filtration is a tried and tested technology. It removes up to 99.99% of hundreds of different contaminants that could be present in your water supply giving you access to safe and healthy reverse osmosis drinking water.
  • Filtration speed is solid.
  • Setting up a countertop RO unit takes no more than a few minutes and doesn’t involve plumbing or drilling. The non-permanent installation is great if you’re a renter.
  • RO filter system maintenance is nice and easy, and affordable!
  • All countertop reverse osmosis water filter systems are compact. And some are even suited for travelling.
  • Reverse osmosis doesn’t rely on electricity. All you need is a standard-sized faucet with enough water pressure.

Disadvantages

  • Units fit standard kitchen faucets only.
  • Some people don’t like the taste of RO water.
  • Reverse osmosis produces wastewater.
  • RO water lacks minerals. You can use a remineralization filter to solve this!

Small, Compact & Portable – Perfect for Camping?

In our opinion, portable countertop reverse osmosis water purifiers are perfect for camping, since they’re small and compact.

Now you might be thinking, why would I use a water filter when I’m in the great outdoors? I can either bring bottled water or drink the water Mother Nature provides. Yeah, well…

  • Natural and man-made water contamination does not stop at creeks, ponds, lakes or any other surface or groundwater source.
  • Most bottled water is literally municipal tap water filled into a bottle.

So remember: Whenever you go on a camping trip and there’s a standard-sized faucet, always bring your portable RO filter system.

Frequently Asked Questions (FAQ)

  • Is reverse osmosis worth it?
    Definitely. Reverse osmosis water filtration provides exceptionally pure water.
  • Do I need reverse osmosis if I have a whole house filter?
    Most whole house water filters aren’t effective enough to provide water that’s safe to drink. A reverse osmosis water filter system makes a great addition.
  • How much does a home reverse osmosis water filtration system cost?
    It depends on the type. You can spend anywhere between $50 and $500 USD.

How We Chose and Tested the Best Countertop Reverse Osmosis Systems (Why Trust Us)

Our methodology for reviewing countertop reverse osmosis systems involved several steps:

  1. We created a list of 19 criteria to evaluate all products against, based on our experience and research.
  2. We compiled a list of over 26 countertop RO models available online.
  3. We thoroughly examined product manuals, descriptions, third-party certifications (NSF and other), and warranties. We also conducted interviews with several brands (like Waterdrop, NU Aqua, Aquasana, Home Master, AquaTru) to assess their support level. Through this process, we narrowed down our list to 16 systems.
  4. To ensure we included only the best, we checked for feedback and ratings from real users on various platforms, while rejecting any fake reviews.
  5. After these steps, we were left with 8 products, which we ordered and installed – we followed the provided setup instructions carefully – to gain hands-on experience. We evaluated each filter from multiple angles, including ease of installation/maintenance, overall ergonomics, flow rates, and filtered water taste and odor, and allowed them to operate for at least 2 weeks.
  6. We conducted our own lab testing using a service called Tap Score to measure real-life contaminant reduction rates. We also analyzed water pH, TDS, hardness, and more.
  7. Finally, we analyzed all the gathered information, converting technical specifications into easy-to-understand insights, and presented everything in a pros vs cons format.
  8. It is important to note that all the information and ratings presented in our reviews are independent and unbiased. We also have professionals fact-checking our content for accuracy. (The evaluation of contamination reduction claims was a significant task carried out by . This included verification of NSF and other certifications and thorough examination of lab reports/test data.)

About Our Ratings

Currently, our evaluation process for countertop reverse osmosis systems is mostly based on these key factors: NSF-based contamination removal rates (30%), affordability (includes maintenance cost) (25%), direct testing and third-party user ratings (20%), filter capacity (15%), product warranty and support (10%).

We’ve rated each system on a score of 1 to 5, with 5 being the highest rating.

Questions? Ask away!

About the Author Alexandra Uta

Alex is a content writer with an affinity for research and a methodical attention to detail. Since 2020, she has fully immersed herself into the home water treatment industry only to become an expert herself. Alex has been using water filters and similar products for years which has gained her lots of hands-on experience.
Learn more about .

Alex

Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment:

Don Weeks says August 17, 2019

I live alone in Canada and looking for a counter top unit that is modest priced and uses a diverter valve on the sink faucet and where the filter elements and membranes are readily available at Home Depots of Home Hardwares , Walmarts, etc. Are any units you suggest available at any of these retailers? Thanks

Reply
    Gene says August 19, 2019

    Sorry Don, I can’t suggest any system.

    Reply
STEPHANIE L NEWSOM says February 3, 2020

I’d like to see a ROS that’s truly portable. I go places where there’s no water spigots and sometimes no water at all. I’m not stupid enough to fill my containers from those disgusting water dispenser machines.

Reply
    Gene says February 10, 2020

    Stephanie,
    Reverse osmosis requires external pressure. Otherwise it won’t work.

    Reply
Amanda says March 21, 2020

What is your best recommendation for renters? I live in NYC and space is a luxury and we don’t want to put hole in countertop for spout. Any suggestions? Thank you

Reply
    Gene says May 1, 2023

    The AquaTru!

    Reply
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