5 Best Countertop Reverse Osmosis Water Filter Reviews (+ Portable RO Systems)

Author: Jason Hollow - Published: 2020/12/04 - Updated: 2023/01/05

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Countertop reverse osmosis systems offer the most thorough filtration of all countertop water filters.

At the same time, they are installation-free – unlike under sink RO systems which need two connections: One to the cold water line and one to the drain line. Setting up an under sink reverse osmosis system also requires you to drill a hole in your kitchen sink or counter to accommodate the extra faucet.

But not with countertop units; they are either standalone or can be quickly connected to any standard faucet. This is the perfect solution for people who can’t or don’t want to make permanent changes to their plumbing.

Another benefit of countertop RO systems is compactness. They are small and thus ideal for small apartments, RVs, and people in general who need a portable water filter.

So, here is our collection of the 7 best countertop and portable reverse osmosis systems. Enjoy!

Best Countertop Reverse Osmosis Systems – Top Picks

ProductsSpecs & FeaturesWhere to Buy
Best Overall
AquaTru Reverse Osmosis Water System AquaTru Reverse Osmosis Water System


  • Price: $$$
  • Filter Stages: 4
  • Water Production: 1 Gallon in 10-15 Minutes
  • NSF/ANSI: 42, 53, 58, 401, P473
  • Best For: Most Comprehensive Filtration (NSF-Certified)

Coupon Code (15% Off): WATERMASTERZ

Or read our review

RKIN Zero Installation Purifier Countertop Reverse Osmosis Water Filter RKIN Zero Installation Purifier Countertop Reverse Osmosis Water Filter

RKIN Zero Installation Purifier

  • Price: $$$
  • Filter Stages: 4
  • Water Production: 1 Gallon in 10-20 Minutes
  • NSF/ANSI: 58
  • Best For: Alkaline Drinking Water

Or read our review

Best Portable
Crystal Quest Thunder Portable Reverse Osmosis System Crystal Quest Thunder Portable Reverse Osmosis System

Crystal Quest Thunder


  • Price: $$
  • Filter Stages: 10
  • Water Production: 0.03 Gallons Per Minute
  • Best For: Portability

Or read our review

Best Countertop Reverse Osmosis System Reviews

The order of the following countertop reverse osmosis system reviews is deliberate. Our favorite products are at the top.

1. Best Overall: AquaTru Reverse Osmosis Water System

Coupon Code (15% Off): WATERMASTERZ

In our opinion, the best countertop reverse osmosis system in 2023 is the AquaTru.

First and foremost, the AquaTru Reverse Osmosis Water System is NSF-certified to remove more than 80 potential contaminants that could be present in your water supply. Tested standards are 42, 53, 58, 401, and P473.

For your information: Buying a water filter that has NSF certifications is the best way to get access safe and healthy drinking water. In addition, the filtered water also tastes and smells much better.

Other benefits of the AquaTru are the simple 5-minute setup and fast and affordable filter replacements.

AquaTru countertop Reverse Osmosis Water System


See More Product Images at waterandwellness.com

Main Specs

  • Price: $$$
  • Filter stages: Four-stage system
  • Flow: System processes 1 gallon of water in 10-15 minutes
  • Estimated annual filter replacement cost: $120
  • NSF: 42, 53, 58, 401, P473
  • Best for: The AquaTru system is the best for RO purification overall.

AquaTru Reverse Osmosis Water System a AquaTru Reverse Osmosis Water System b


  • The AquaTru is easy to use and space-saving.
  • It features 4 stages of filtration: A combination of sediment and activated carbon pre-filter removes rust, silt, sand, and other larger particles to prevent clogging of the rest of the system. The carbon also adsorbs 96.6% chlorine taste and odor, and a range of chemical and organic contaminants. The pre-filtration is followed by the reverse osmosis membrane which rejects 99.1% lead, 97.2% hexavalent chromium, 93.5% fluoride, 96.4% radium[1], and much more. Lastly, a coconut shell carbon block filter catches pesticides and herbicides, volatile organic compounds, 97.5% PFOA & PFOS, and pharmaceuticals.
  • NSF/ANSI Standard 42, 53, 58, 401, and P473 certifications guarantee filtration effectiveness.
  • Processing 1 gallon of water in 10 to 15 minutes is fast. This can be achieved with the help of an internal water pressure pump. The pump also lowers the waste water ratio so that no more than a quarter gallon goes down the drain for every gallon of filtered water (the standard is 3 gallons to 5 gallons of water wasted).
  • The clean water tank comes with a one-button dispenser and can be removed to be stored in your fridge.
  • The dirty water collects in a second tank which you can empty in your sink.
  • Putting the AquaTru together couldn’t be easier – it’s a standalone unit. You certainly don’t need to be a skilled do-it-yourselfer. The whole process barely takes five minutes of your time.
  • The different filters last between 6 months and 2 years. Changing them is self-explanatory. New filter cartridges are quite affordable.
  • All plastic is Tritan and therefore free from BPA and BPS.
  • A 1-year warranty covers the unit against defects in materials or workmanship in manufacturing.
  • Customer service is great.


  • A few people reportedly had issues with leaking systems.
  • For a small percentage of users, the system began to malfunction several months after purchase.

Or read our complete AquaTru water filter review

2. Best for Alkaline Water: RKIN Zero Installation Purifier Countertop Reverse Osmosis Water Filter

Coupon Code (8% Off): WM8Percent

The RKIN Zero Installation Purifier, or short ZIP, is another of our favorites. Just like the AquaTru, it’s a standalone countertop RO system which means its installation doesn’t involve plumbing or anything like that. In fact, assembling the unit before first use only takes a couple of minutes.

What’s different about the RKIN ZIP compared to the AquaTru is that it uses a remineralization filter to enrich the drinking water with healthy minerals.

RKIN Zero Installation Purifier Countertop Reverse Osmosis Water Filter


See More Product Images at Purewaterguys.com

Main Specs

  • Price: $$$
  • Filter stages: Four-stage system
  • Flow: System produces one gallon of pure water in 10-20 minutes
  • Estimated filter replacement cost per year: $70
  • NSF: 58
  • Best for: The RKIN ZIP is ideal for alkaline water.


  • As a standalone RO system the ZIP is easy to use, compact, and doesn’t require much space on your kitchen countertop.
  • The system uses a 5-micron sediment filter, an activated coconut shell carbon block filter, an RO membrane, and a granular activated carbon and remineralization post-filter to remove up to 99% of water contaminants including: Sediments, chlorine, disinfection byproducts, heavy metals, VOCs, and all kinds of chemicals and organics.
  • The remineralization filter adds calcium and magnesium into the purified water for an even better taste and improved alkalinity.
  • Instead of the regular sediment and carbon pre-filter, you can use an anti-scale filter suited for hard water and water high in TDS (total dissolved solids). This helps to increase the overall service life of the two other filter elements.
  • A pump boosts water pressure for higher filtration speed and an improved water recovery rate of 50%.
  • The water tanks are BPA-free.
  • Easy installation.
  • Filters are long-lasting which is great. What’s more, they can be replaced quickly using a twist on/off mechanism or quick-connect fittings. You don’t even need to remember the date of the last filter replacement. An LED light on the front panel will remind you whenever one of the filters has reached the end of its service life.
  • 1 year money-back guarantee means you can try the ZIP for a full year. During this period you can return it for a full refund, no questions asked.
  • There’s a 1-year product warranty.


  • Only the reverse osmosis membrane has been certified according to NSF/ANSI standards.
  • There are known issues with leaking from different parts of the system.
  • The tank which starts the filtration process is known to cause problems with some units.

3. Best for Portability: Crystal Quest Thunder Portable Reverse Osmosis System

In our opinion, the best portable reverse osmosis system in 2023 is the Crystal Quest Thunder. That’s because it is super small and can be attached and removed from any standard-sized kitchen faucet or bathroom tap in less than 1 minute.

Crystal Quest Thunder Countertop Reverse Osmosis System


See More Product Images at crystalquest.com

Main Specs

  • Price: $$
  • Filter stages: 10
  • Flow rate: 0.03 gallons per minute, up to 50 gallons per day
  • Estimated annual filter replacement cost: $75
  • Best for: The Crystal Quest Thunder is ideal for those wanting quality portable filtration.


  • At 16x7x7 inches, the Crystal Quest Thunder Portable Reverse Osmosis Filter System is one of the most compact models on the market – great for travelling. It can be stored in an RV with ease and might even fit in your suitcase.
  • On its way through the system, water has to pass through ten filtration stages: Granular activated carbon (GAC) filtration, RO membrane purification, Eagle Redox alloy oxidation & reduction, and ion exchange resin treatment remove sediments, chlorine (99.9%), benzene, TTHM, cyst, pesticides, herbicides, VOCs, lead, mercury, copper, aluminum, nickel, cadmium, salts, and more. In the end, your home’s water will be clean and free from bad taste and odor. Above that, the Redox alloy controls microorganisms.
  • Between each two filter stages, one-micron filter pads prevent clogging.
  • The Crystal Quest countertop and portable RO system is compatible with any standard faucet. Various adapters are part of the package.
  • The carbon filter lasts up to 18 months; the semi-permeable membrane and the SMART filter 2 to 3 years. In other words, maintaining the Crystal Quest Thunder really is not a big deal.
  • A warranty covers the system for one year.


  • As with most portable RO filter systems, water flow isn’t that high. That’s why it makes sense to use the filter together with a large container which you can fill overnight for example.
  • Crystal Quest does not provide a performance data sheet with reduction rates for certain contaminants. We can only assume that the system hasn’t been tested or certified against NSF standards.

Or read a detailed Crystal Quest RO system review

4. Review: APEC Water Systems RO-CTOP Portable Countertop Reverse Osmosis Water Filter System

The APEC Water Systems portable RO system is a viable alternative to the Crystal Quest Thunder.

Most importantly, it is as easy to connect and use, compact, and provides great-tasting drinking water.

APEC Water Systems Portable Countertop Reverse Osmosis Water Filter System


See More Product Images at amazon.com

Main Specs

  • Price: $$
  • 4-Stage Filtration System
  • Flow: 4 gallons every two hours, around 50 gallons per day
  • Estimated annual filter replacement cost: $120
  • NSF certified: 42
  • Best for: The APEC 4-stage filtration system is best for travelling.


  • The small and lightweight tankless design is perfect for portability.
  • A four-stage filter process – 5-micron polypropylene sediment pre-filter, coconut shell granular activated carbon filter, Dow FILMTEC RO membrane, granular coconut shell activated carbon filter – removes up to 99% of contaminants, says APEC. This includes lead, chlorine, odors and tastes, fluoride, arsenic, chromium 6, radium, sediments, cloudiness, colors, VOCs and other chemicals, bacteria, viruses, and overall TDS (98-99%).
  • You can substitute the last filter stage with a remineralization filter to enrich your water with essential calcium. This helps with flat taste and water acidity.
  • Thanks to a diverter valve you can switch between unfiltered and filtered water without disconnecting the APEC RO-CTOP.
  • Installing the filter is super fast. A set of adapters are part of the package. Only standard-sized taps are compatible.
  • Each filter stage has quick-connect fittings so that changing cartridges is as simple as it possibly gets. The pre-filters need replacement twice a year. Reverse osmosis membrane and post-filter last much longer. Overall, the costs seem legitimate considering that all filters are manufactured domestically.
  • The limited warranty is valid for one year.


  • People have complained about the tubing becoming brittle and therefore prone to leaking or blowing off after some time.
  • The APEC RO-CTOP misses a proper faucet. Water exits via a tube.
  • There is only one NSF/ANSI certification for the removal of chlorine.

Or read our complete APEC RO-CTOP review

5. Best Looks: KFLOW KFL-ROPOT-180 Countertop Reverse Osmosis Water Filter

KFLOW’s KFL-ROPOT-180 water filter comes in at fifth place.

According to the seller, the system removes more than 1,000 water contaminants including lead to “transform ordinary tap water into clean, delicious and alkaline water“. Users say that the water tastes good, however, we are not quite sure yet how the system is supposed to provide alkaline water when there’s no alkalinization or remineralization stage.

One thing is for certain, we are talking about an RO system that requires zero installation: Plug in and use!

KFLOW KFL-ROPOT-180 Countertop Reverse Osmosis Water Filter


See More Product Images at amazon.com

Main Specs

  • Price: $$$
  • Filter stages: Four-stage system
  • Estimated filter change cost per year: $150
  • Best for: The KFLOW is best for those who want a good looking filter.


  • Nice design! You can choose between white and black.
  • The countertop water filter system is advertised to remove taste, odor, turbidity, fracking chemicals, herbicides, fertilizers, drug residue, chromium 6 and other heavy metals, organic impurities, chlorides, nitrosamine, trihalomethane, cadmium, and cysts – and this is only an excerpt. Filter stage one is a 5-micron sediment filter followed by a .5-micron coconut carbon block filter. The third filter stage is the RO membrane. At last comes a coconut carbon block filter.
  • There is no installation requirement. Simply fill the water tank and hit the start button.
  • You are not limited by a water source. You can place and move KFLOW anywhere with a power supply.
  • The system allows for convenient 3-second filter replacements (sounds like a new record). Plus, you can rely on the digital display to tell you how much capacity the filter cartridges have left (the membrane lasts 2 years, all other filter elements 1 year).


  • The KFLOW KFL-ROPOT-180 uses a carafe instead of a water storage tank which is fine. It’s just that the carafe is a bit small.
  • One reviewer said his system broke after 3 months of use no longer making any filtered water.

Countertop Reverse Osmosis Water Filters Comparison Chart

How do the top countertop RO water filters perform when directly compared to each other?

Reverse Osmosis Filters$$$Filter StagesFlow RateAnnuallyNSF/ANSIBest ForDetails
AquaTru Reverse Osmosis Countertop$$$41 Gallon in 10-15 Minutes$12042, 53, 58, 401, P473Best OverallCoconut Shell Activated Carbon Filter + Sediment Filter, BPA-free, Provides High Amounts of Water Per Day, No Installation Required
RKIN ZIP 4-Stage RO Water Filter System$$$41 Gallon in 10-20 Minutes$7058Best for Alkaline WaterEasy to Use, BPA-Free, No Installation Required
Crystal Quest Thunder Purification System$$100.03 gpm, Up to 50 Gallons Per Day$75Best Portable UnitHigh Quality System is Designed for Portability
APEC Water Systems Four-Stage Filtration System$$44 Gallons in 2 Hours, Around 90 Gallons Per Day$12042Best for TravellingPost Activated Carbon Filter, Removes 98-99% TDS (Total Dissolved Solids), Provides Great-Tasting Water on Demand, Easy to Install, Easily Portable
KFLOW KFL-ROPOT-180 Reverse Osmosis Countertop$$$4?$150Best LookingNo Installation Required, Quick-Change Filters

Buying Guide – How to Buy a Countertop or Portable RO Water Filtration System (+ How We Tested)

A countertop reverse osmosis water filtration system has many benefits if you choose one that’s up to standards. Below is our buyer’s guide so you don’t make the wrong purchase decision.

Faucet Connection/Installation

Countertop RO water filters are only compatible with standard-sized faucets or taps. Designer faucets, pull-down faucets, and sprayer faucet won’t work.

To make sure that your faucet is compatible make sure that it allows for a hose connection. Usually, you don’t need to worry about buying an adapter. Most water filtration systems have several adapters included.

NSF/ANSI Certifications

Generally speaking, RO water purification is highly effective and removes a broad range of contaminants. Nevertheless, you want to purchase a filter system tested and/or certified against NSF/ANSI standards. It’s the only way to guarantee effective contaminant removal. Furthermore, some NSF certifications cover material safety and structural integrity.

  • NSF Standard 42 tests for the reduction of aesthetic contaminants, mainly chlorine large particulates.
  • Standard 53 is for the reduction of contaminants that can affect our health. This includes heavy metals like lead and chromium, volatile organic compounds, and various chemicals.
  • Standard 58 was established for RO systems only. Tested contaminants are arsenic, cadmium, chromium 6, fluoride, lead, nitrate, and many others.
  • NSF/ANSI 401 addresses a group of 15 water contaminants which have been emerging in recent years but are not yet regulated by the Environmental Protection Agency – think prescription drugs, pesticides, herbicides, and chemicals.
  • P473 covers highly dangerous Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).


It is much harder to hide a countertop water filter so choose one that you actually like to look at.

Water Pressure and Wastewater

Simply put, all reverse osmosis water filter system produce wastewater. The question is: How much water goes to waste for every gallon of clean water? This is mainly influenced by incoming water pressure. Higher pressure means less wastage.

The good news is, some countertop RO filters have pressure pumps built in, like the AquaTru and the ZIP. This increases the ratio of pure water to reject water, also called recovery rate, significantly.

For example: A system with a recovery rate of 50% means out of 2 gallons of unfiltered water it processes you can drink one while the other ends up in the drain as reject water.

Water Production

What good is a water filter if it cannot meet your demand for clean drinking water on a daily basis? If you want to avoid being thirsty make sure your new countertop RO system filters fast enough. Or use a large container that you can fill.

Maintenance and Filter Life

Reverse osmosis systems used multiple filter stages. Most last between 6 and 12 months. The high capacity reverse osmosis filtration membrane at the heart of a system can last up to several years. As a result, maintenance requirements are low and most of the time replacing filters is a quick and simple process anyway.


You don’t need to buy the highest priced system in order to get RO purified water that’s healthy and clean. But don’t go too cheap or you might end up with substandard quality doing more harm than good. Anywhere between $150 and $450 should be fine.

Furthermore, keep in mind to pay attention to maintenance cost which is the largest expense long-term.

What is a Countertop RO System?

best countertop reverse osmosis systems thumbnail large

A countertop reverse osmosis system provides the best filtration in the realm of countertop water filter systems. Water contaminants that can be removed include heavy metals, salts, chemicals, organics, water disinfectants and their byproducts, and so on and so forth.

Most countertop RO systems use at least 3 filters, one pre-filter, the semipermeable membrane, and one post-filter, in their purification process.

As far as installation is concerned, systems are either standalone or can be easily connected to an existing faucet or tap – so no plumbing required.

Of course, no installation and compact design means high portability. Some systems are even small enough to take with you while you are travelling.

How Does a Countertop Reverse Osmosis Filter Work?

As previously mentioned, just like regular reverse osmosis filters countertop units feature multiple stages of filtration for the removal of a broad range of contaminants.

  • Stage 1 of the filter process is usually a sediment filter. This filter type is great for catching larger particulates and prevent them from clogging the other filter stages.
  • The next step of pre-filtration could be a carbon block. Activated carbon neutralizes water disinfectants like chlorine, their byproducts, all kinds of chemicals, VOCs, and overall bad water taste and odor.
  • A reverse osmosis membrane removes well above 95% of the total dissolved solids (TDS). This is where the majority of impurities will be removed from your water.
  • Granular carbon takes care of the post-filtration. It is used to give the water a finishing touch.
  • Remineralization filters are optional. They enrich RO purified water with calcium and magnesium for a well rounded taste and a balanced pH.

How Reverse Osmosis Works

Let’s briefly touch upon how the reverse osmosis filtration technology works:

The natural osmosis process[2] occurs when two salt solutions of different levels are separated by a semi-permeable membrane. Due to osmotic pressure, the solvent will move from the low to the high salt solution until the salt concentrations on either side of the membrane are equal.

With reverse osmosis, external hydraulic pressure is applied to the side with the high solute concentration. If the hydraulic pressure outweighs the osmotic pressure, the direction of the solvent flow is reversed. It now moves from the high to the low salt solution. Eventually, you have an even higher concentrated salt solution on one side and a very weak solution on the other.

Transferred to real life, the weak salt solution is the filtered water that leaves a reverse osmosis system ready for consumption. The high salt solution is the wastewater. And the external hydraulic pressure is the water pressure in your plumbing system.

Frequently Asked Questions (FAQ)

FAQ thumbnail

Is a reverse osmosis water filtration system worth it?

Yes, it is. A reverse osmosis water filter system provides the best filtration of all water filter types and water quality is much better than bottled water.

What is the disadvantage of RO water?

There are two disadvantages: One is that taste can be flat. The other is the sometimes slightly acidic pH. Both can be resolved through remineralization.

How much does an over-the-counter home reverse osmosis filter cost?

The most affordable models start at less than $100. However, we recommend paying a little more for a high quality unit. Just don’t pay more than $450 to $500. Anything above $500 is definitely overpriced.


A reverse osmosis filter can make a great addition to your home. You just need to buy one that’s up to standards. Our first choice is the AquaTru. The ZIP is also one of the best. If you want an easily portable unit we recommend the Crystal Quest Thunder.

If you have any questions about our countertop reverse osmosis reviews or any other reverse osmosis water filters please leave a comment below!

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Meet Jason Hollow

Jason Hollow Jason is the founder of Water Masterz and head of content creation. After six years in the industry, he has tremendous knowledge and first-hand experience on all things related to water treatment.

His credo: Not a single American should have to drink unhealthy water at home.

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