We’ve tested dozens of countertop reverse osmosis systems in our 10+ years of developing content for WaterFilterGuru.com. We selected and ranked the 5 systems on this list based on their water treatment process, production rate, efficiency, and overall value for money.
If you’re having trouble knowing which countertop reverse osmosis system is right for you, you’re certainly not alone. Countertop RO is still emerging as a relatively new concept (most RO units are designed for under-sink installation), and reverse osmosis systems in general have a more technical performance that you might struggle to get your head around at first.
But with reverse osmosis being one of the most comprehensive and effective ways to remove contaminants from your water, it’s a water filtration solution that’s definitely worth looking into. Countertop RO systems are particularly beneficial, offering the perks of reverse osmosis without the difficult installation of an under-sink or whole-home unit (making them perfect for use in apartments)
If you’re pretty certain that you want to buy a countertop reverse osmosis system but you don’t know where to begin, you’ve come to the right place. In this guide, we’ve reviewed and shortlisted our top recommended countertop RO systems based on our own personal experience using the systems, which allowed us to impartially provide experience-backed feedback on each product’s performance.
Table of Contents
- 🥇 Best Countertop Reverse Osmosis System
- 📊 Comparison Chart of Countertop Reverse Osmosis Systems
- 🏷️ The Best Countertop Reverse Osmosis Filters in the News: The Latest Deals and Discounts
- ⭐ Countertop Reverse Osmosis System Reviews 2023
- 📚 Methodology: How We Tested The Best Countertop RO Systems
- ❔ Frequently Asked Questions
🥇 Best Countertop Reverse Osmosis System
- Best Overall: RKIN U1
- Popular Chouce: AquaTru
- Runner Up: Waterdrop WD-N1-W
- Best for Hot Water Dispensing: NU Aqua 4-Stage Countertop Reverse Osmosis System
- Budget Option: Crystal Quest Portable Reverse Osmosis System
📊 Comparison Chart of Countertop Reverse Osmosis Systems
|System||RKIN U1||AquaTru||Waterdrop WD-N1-W||NU Aqua CTRO||Crystal Quest
|Filtration||5 stages||4 stages||2 stages||4 stages||10 stages|
|Production Rate||75 GPD||~1 GPM||75 GPD||75 GPD||50 GPD|
|Holding Capacity||0.50 gallon||0.75 gallons||0.39 gallon||1 gallon||0.30 gallon|
|Certifications or Testing||NSF 58 (in progress)||NSF 42, 53, 58, 401, P473||NSF 58, 372||NSF 58||–|
🏷️ The Best Countertop Reverse Osmosis Filters in the News: The Latest Deals and Discounts
A big part of what we do is to help our readers find the best water filters at the best price. We spend a lot of time checking the markets for deals and discounts, and if we’ve found any for the countertop RO systems in this guide, we’ve shared them below.
- Get up to 50% off with Waterdrop’s Black Friday Sale, ends November 16
⭐ Countertop Reverse Osmosis System Reviews 2023
In our opinion, the RKIN U1 is the best overall countertop reverse osmosis system. Newly launched at the end of 2022, this sleek, modern countertop water filter dispenses both hot and cold RO purified water and removes an impressive 99% of all contaminants with five filter stages. We love this system’s 75 gallon per day water production rate, and it’s reassuring to see that it’s backed by a 1-year money-back guarantee and is on its way to obtaining an NSF Standard 58 certification.
|Production Rate||75 GPD|
|Holding Capacity||0.50 gallon|
|Certifications/Testing||NSF 58 (in progress)|
The U1 is the best countertop RO system we’ve ever reviewed when it comes to water treatment performance and features. It’s completely unique from any other countertop unit, with two features we rarely (if ever) see alone, let alone together: hot and cold water dispensing and hydrogen infusion. Out of the box, we thought the system looked the part in our kitchen, with a sleek, modern, silver and black design, similar to a coffee maker – just bigger. It arrived partially assembled, and the filters and water tank were hidden inside or at the back of the unit, so we only had the attractive exterior to look at from the front.
When we got the U1 for testing, it was being sold at around $575 – around $100-150 steeper than other systems, but definitely still great value considering its additional unique offerings. Our anticipated annual spend on maintenance, including replacing the three filters, was $100-$150.
|2-Year Filter Bundle||$290|
Folks who want the very best that countertop reverse osmosis has to offer, with all the mod-cons, presets, and handy features – and are happy to pay a premium price for the experience.
What We Like:
- IAPMO tested performance (official NSF certification impending)
- Sleek, modern design
- Additional unique features, including hydrogen infusion and hot/cold water dispensing
- Remineralization filter included (not as an add-on)
What We Don’t Like:
- More expensive than most similar systems
- Costs extra to extend the warranty – we wish this was included in the price
Superior Performance Features
The RKIN U1 has all the key filtration stages that we’d expect to see from any countertop reverse osmosis unit: a sediment filter, an activated carbon filter, and an RO membrane. What made it unique from any of the other systems we tested was that it also featured an alkaline post filter (rather than being an optional extra, as with most other systems we reviewed), plus a hydrogen infusion filter, which we have otherwise only ever seen on water treatment systems that cost thousands of dollars. We were relieved to see that these 5 filtration stages were packed into just 3 filter cartridges, reducing the number of separate filters we’d have to worry about changing.
We were able to do a before-and-after water test to see how well the U1 could remove contaminants from our water supply in Steamboat Springs, CO. Our initial unfiltered water TDS reading was 112 23 mg/L, and the U1 reduced it by about 79.5%, to 23 mg/L. We also had traces of fluoride, copper, lead, uranium, chloride, molybdenum, and zinc in our water, which the U1 reduced completely, by 100%. The hydrogen infusion stage gave our water a negative ORP reading of 340, and the remineralization filter introduced healthy alkaline minerals, imparting a pleasant mineral taste (as opposed to the “flat” taste of demineralized RO water).
An overview of the RKIN U1’s performance, based on our third-party laboratory analysis, is provided below.
|Barium||0.014 PPM||0.0087 PPM||37.86%|
|Calcium||23.9 PPM||3.6 PPM||84.94%|
|Chloride||9.2 PPM||0 PPM||100%|
|Copper||0.0525 PPM||0 PPM||100%|
|Fluoride||1.5 PPM||0 PPM||100%|
|Lead||0.0009 PPM||0 PPM||100%|
|Magnesium||6.08 PPM||0.39 PPM||93.59%|
|Molybdenum||0.0047 PPM||0 PPM||100%|
|Nitrate (as N)||2.1 PPM||0.2 PPM||90.48%|
|Phosphorus||1.1 PPM||0 PPM||100%|
|Sodium||9.91 PPM||1.2 PPM||87.89%|
|Strontium||0.108 PPM||2.42 PPM||+2140.74%|
|Sulfate||7.6 PPM||1.6 PPM||78.95%|
|Total Dissolved Solids||112 PPM||23 PPM||79.46%|
|Uranium||0.0182 PPM||0 PPM||100%|
|Zinc||0.559 PPM||0 PPM||100%|
We know that many folks feel more reassured spending money on a system with official testing or certifications, so we were pleased to learn that the U1 has IAPMO testing for the reduction of TDS, chromium 3 and 6, fluoride, lead, PFOA, and PFOS. Even better, a customer rep at RKIN told us that they’re currently in the process of obtaining an official NSF certification for the U1.
Modern, Efficient RO Purification Solution
The design team for the U1 has obviously thought long and hard about the features that customers find genuinely helpful on a reverse osmosis system – and they included them all! We loved the smart display screen, which let us select different presets and custom water temperatures (being able to dispense hot water straight from the unit was a next-level benefit for us). We also found the filter life indicator super handy, and the 1:1 efficiency ratio – meaning that only 1 gallon of water was wasted for every 1 gallon purified – is pretty much in line with what we’re used to seeing from more modern systems nowadays.
Were there any performance setbacks for us to note? Nothing out of the ordinary, but there are a few things to keep in mind for a unit of this type. For instance, we found we were emptying and refilling the tanks a lot due to the lack of a connection to our water line. The unit’s filtered water capacity is half a gallon, so if you have a big family, prepare to top up the water and empty the wastewater tank often. Good news, though: the 75 GPD water delivery rate meant the unit could filter a full half-gallon batch in less than 7 minutes, which we thought was pretty fast.
Read the full review: RKIN U1 2023 review
The AquaTru is a close runner-up to our top pick and another highly popular countertop RO system. This system has been IAPMO certified to NSF standards 42, 53, 58, 401, and P473, for the removal of an impressive 82 different contaminants in drinking water. Plus, its flow rate and holding capacity are significantly higher than any other units on this list, and it’s cheaper than our top pick, the RKIN U1. If it’s quality filtration you’re after, the AquaTru should tick your boxes – and all for less than $400.
|Production Rate||~1 GPM|
|Holding Capacity||0.75 gallons|
|Certifications/Testing||NSF 42, 53, 58, 401, P473|
The AquaTru has the same design concept as the RKIN U1, except that it’s less linear, with a narrower front that opens out into a wide back, and a good portion of the unit is taken up by the transparent water tank. When we tested the system, we had the choice of four different configurations:
- The Classic, which provides standard RO filtration.
- The Connect, which is the same as the Classic but also features built-in WiFi and connects to an app that gives you insights into the filter performance.
- The Alkaline Classic, which has an alkaline mineral boost VOC filter instead of the standard VOC filter. (We tested this system!)
- The Alkaline Connect, which has both additional features mentioned above.
|Classic||RO + VOC Filter||$449|
|Connect||Wifi RO + VOC Filter||$499|
|Alkaline Classic||RO + Alkaline Boost VOC Filter||$469|
|Alkaline Connect||Wifi RO + Alkaline Boost VOC Filter||$519|
If you’re wondering why we went for the Alkaline Classic model, we’ll always go for an RO system with a remineralization option whenever it’s available. Like most people, we find the flat taste of demineralized water a bit boring, and given that the Alkaline Classic costs around $20 more than the AquaTru Classic, we thought it was worth the investment rather than worrying about remineralizing our water ourselves. Depending on the model you go for, you’ll spend between $450 and $520 – a bit less than the U1, which makes sense given that the AquaTru doesn’t have all the U1’s unique features. Based on the cost of filter replacements, we think we’ll be spending around $100 annually on maintenance.
Folks who want to spend less money upfront on a countertop RO system that doesn’t quite offer as many features as the RKIN U1 but wastes less water.
What We Like:
- IAMPO certified to remove 80+ contaminants
- One of the best efficiency ratios we’ve seen (4:1)
- Helpful digital display with filter change reminders
- Affordable upgrades to WiFi-connected units and models with remineralization filters
What We Don’t Like
- Only dispenses cold water
- Model with remineralization filter costs extra
Performance Certified By IAPMO
While the RKIN U1 has been IAMPO tested for its performance, it doesn’t yet hold an official certification. We know that a lack of official certifications is a dealbreaker for some folks – and if that’s you, you’ll be happy to hear that the AquaTru holds an IAMPO certification to NSF Standards 42, 53, 401, and P473, for its ability to remove 82 contaminants. These include TDS, radium, nitrate, nitrite, arsenic, fluoride, lead, chromium, and barium. When we taste-tested our filtered water and compared it to our unfiltered water from the faucet, we noticed a significant improvement in freshness, purity, and quality. Because we’d upgraded to the Alkaline Classic system, our water had a slight mineral crispness thanks to the final-stage remineralization VOC filter.
Here’s a summary of AquaTru’s performance as evaluated through our third-party laboratory analysis.
|Barium||0.014 PPM||0 PPM||100.00%|
|Calcium||23.9 PPM||0.7 PPM||97.07%|
|Chloride||9.2 PPM||0 PPM||100.00%|
|Copper||0.0525 PPM||0 PPM||100.00%|
|Fluoride||1.5 PPM||0 PPM||100.00%|
|Lead||0.0009 PPM||0 PPM||100.00%|
|Magnesium||6.08 PPM||0.36 PPM||94.08%|
|Molybdenum||0.0047 PPM||0 PPM||100.00%|
|Nitrate (as N)||2.1 PPM||0 PPM||100.00%|
|Phosphorus||1.1 PPM||0 PPM||100.00%|
|Sodium||9.91 PPM||0 PPM||100.00%|
|Strontium||0.108 PPM||0 PPM||100.00%|
|Sulfate||7.6 PPM||0 PPM||100.00%|
|Total Dissolved Solids||112 PPM||12 PPM||89.29%|
|Uranium||0.0182 PPM||0 PPM||100.00%|
|Zinc||0.559 PPM||0 PPM||100.00%|
Impressive Efficiency Ratio
The AquaTru RO system’s 4:1 performance efficiency is up there with the best we’ve seen – and it’s better than the RKIN U1’s 1:1 efficiency ratio. If you want to waste as little water as possible in the RO purification process, go for the AquaTru system: it only wastes 1 gallon of water for every 4 gallons of water purified. That said, the unit still wastes some water, so we still had to manually empty the wastewater tank whenever it became full.
Another performance feature we wanted to measure was speed of water delivery. The filtration process itself was relatively fast because of an electric booster pump inside the unit, but we needed more patience when it came to actually accessing our water. The purified water gets stored under pressure in a gravity tank, and as the tank empties, the flow of water gets slower. That meant it took longer to fill a glass when the tank was almost drained.
Tech-wise, we didn’t see all the exciting features offered by the U1. There’s no hot and cold water dispensing, but this really is a rare feature in any water treatment system. What we did have was a digital display screen, which helped us to keep track of the filter lifespan without having to make a manual calendar note to buy new filters. And, of course, there’s the option to upgrade to the WiFi Connect system if you like the idea of being able to track metrics like filter lifespan, water consumption, and water quality on a dedicated app.
Read the full review: 2023 AquaTru Review
The Waterdrop WD-N1-WCountertop System is our second runner-up countertop RO system. We think this unit has its own unique appeal, thanks to its sleek, easy-use design, more affordable upfront price, hourly UV sterilization, and no-fuss, thorough filtration performance.
|Production Rate||75 GPD|
|Holding Capacity||0.39 gallon|
|Certifications/Testing||NSF 58, 372|
The Waterdrop N1 has a very similar design to the U1 from the outside, except that it’s slimmer and smaller because its filter stages are consolidated into just two cartridges. Like the U1, the unit looks modern and sleek, with a digital interface and a water dispenser that allows you to fit a tall bottle or pitcher underneath.
Price was a major selling point of the N1 to us. It’s about $100 cheaper than the AquaTru and over half the price of the RKIN U1, at just under $300, so it’s a great option for people with slightly smaller budgets. Our estimated annual spend on filter replacements was also lower than average, within $70, which is thanks to the fact that there are only two filter cartridges to replace (the CF lasts up to 6 months and the MRO filter can last up to 18 months).
|Waterdrop WD-N1-W Addons||Price|
|WD-N1-CF Sediment and Carbon Block Filter||$36.99|
|WD-N1-MRO Reverse Osmosis Membrane||$49.99|
Folks looking for a more affordable alternative to the AquaTru and RKIN systems that still offers the benefits of a modern countertop RO system.
What We Like:
- Affordable upfront cost
- Up to 100% removal of most dissolved solids
- TDS display with filter life indicator and water shortage indicator
- Built-in UV sterilization for protection against pathogens
What We Don’t Like:
- No remineralization stage
- Not performance certified
Removed 100% of Lead, Fluoride, & More
There are three key filter stages in the Waterdrop N1: PP cotton (which acts as a sediment pre-filter), a carbon block layer, and the all-important semi-permeable RO membrane. No remineralization filter, sadly, which meant we’d have to use mineral drops or just drink plain RO water, which is fine – we just think it doesn’t taste as nice. The unit also performs a UV sterilization once every hour, which targets bacteria and viruses in the feed water. We assume this also helps to keep the system’s internal components microorganism-free.
We couldn’t find official certifications for the Waterdrop N1, although the 0.0001-micron semipermeable membrane used in the unit is the same membrane that’s used in some of Waterdrop’s other certified units. We did have access to Waterdrop’s own test results for the system, which list 17 contaminants that the unit has been tested to remove, including nitrate, fluoride, arsenic, chlorine, total coliforms, lead, and mercury. We were able to test our own water supply to see what contaminants it could remove, and it performed exceptionally well, removing copper, lead, barium, nitrate, phosphorous, molybdenum, uranium, zinc, sulfate, and strontium by 100%. It also removed 93% fluoride, as well as 85% TDS, and up to 91% of various other minerals in our water.
See our laboratory testing data for Waterdrop N1 in the table below.
|Total Dissolved Solids||112 PPM||16 PPM||-85.71%|
|Calcium||23.9 PPM||2.1 PPM||-91.21%|
|Chloride||9.2 PPM||1.3 PPM||-85.87%|
|Fluoride||1.5 PPM||0.1 PPM||-93.33%|
|Magnesium||6.08 PPM||0.5 PPM||-91.78%|
|Sodium||9.91 PPM||2.12 PPM||-78.61%|
The Waterdrop N1 ticked our boxes for its efficiency ratio, too: it’s almost matched with the AquaTru, with a 3:1 ratio (versus AquaTru’s 4:1 ratio). That meant only 1 gallon of water was wasted for every 3 gallons purified in the system, so we weren’t having to empty the wastewater tank more often than we were filling the unit. We found the system generally very easy to use thanks to the smart display screen, which didn’t only give us a TDS reading in real time for our water – it also had a filter life indicator, a personalized water volume setting (so we could simply select the volume that filled our glass every time), and even a water shortage indicator, so we knew when the tank needed a refill. Plus, our maintenance responsibilities were minimal because the system occasionally auto-flushed to clean itself, and we only had two cartridges to change.
Read the full review: Waterdrop Countertop Reverse Osmosis Water Filter System Review (Updated: 2023)
NU Aqua 4-Stage Countertop Reverse Osmosis System
Based on our research, the NU Aqua 4-Stage Countertop Reverse Osmosis System is the best countertop reverse osmosis system for hot water dispensing. This system removes up to 99.99% contaminants and has an unbeatable 5:1 efficiency ratio, and it gives the RKIN U1 a run for its money with its ability to dispense both cold and hot water on demand – at a cheaper upfront cost.
|Production Rate||75 GPD|
|Holding Capacity||1 gallon|
The NU Aqua 4-Stage Countertop Reverse Osmosis System has something of a space-age design that manages to be both modern and unique from your regular kitchen countertop appliances. It’s an all-white unit with a digital control display featured on an angled circular screen, with the dispenser nozzle protruding from underneath. Inside, the tap water tank is at the very back, with the two filter cartridges sitting further forward, and the wastewater tank to the right. The display screen gives you a TDS reading of your unfiltered and filtered water, alerts you when the tank needs a refill, and lets you choose the temperature of the dispensed water.
NU Aqua occasionally offers coupons that give you a certain % discount, and at the time of our review, there was a Halloween sale that knocked 10% off the system, bringing the price down from around $450 to just over $400. Given that the unit can deliver both hot and cold water like the RKIN U1, it’s nice to have an option that’s over $300 cheaper. We estimated that we’d spend within $150 a year on filter changes (the filters don’t last as long; they have a lifespan of up to 6 months).
Folks who drink a lot of hot beverages or use a lot of hot water and want a quick and easy way to produce the purest hot water possible, without the extra features and benefits of the RKIN U1.
What We Like:
- Affordable upfront cost
- Dispenses water at your desired temperature
- Unbeatable efficiency ratio
- Independently tested for performance
What We Don’t Like:
- No official performance certification
- No remineralization filter
Hot or Cold Water at the Touch of a Button
Let’s start with what we think are the two biggest performance perks of the NU Aqua Countertop RO system: its hot and cold water dispensing, and its super efficient pure-to-wastewater ratio. Aside from the RKIN U1, the NU Aqua system was the only countertop RO system that you can use to access both hot and cold water instantly. The heating system has several temperature options, including 100 °F for baby bottle warming, as well as 160 °F, 175 °F, and 200 °F. So, if you drink a lot of hot beverages and don’t want the hassle of boiling your RO water manually, this unit makes a lot of sense. Plus, its 5:1 efficiency ratio is unbeatable – even the AquaTru’s 4:1 ratio isn’t quite as efficient.
Researching the NU Aqua system’s performance, it appears to be pretty unique from most RO systems and might not offer the conventional reverse osmosis performance that we’re used to. We know from the product description that the unit uses multiple filtration stages, including activated carbon and micro-nets, but one of the filters in the unit (as pictured) is an RO membrane. We think you can expect membrane separation from this unit, but NU Aqua says that the unit should retain healthy minerals in the water, which is slightly confusing to us given that the RO process usually removes minerals as a side effect of its comprehensive purification technique. We plan to do a before-and-after water quality test with this system soon so we can see exactly what it removes – and whether it really can retain minerals – and we’ll update our review once we have done.
We couldn’t find any third-party test results for this system, but it has apparently been tested by an independent laboratory to NSF Standard 58, and can greatly reduce up to 99.99% of chlorine, sediment, dirt, sand, VOCs, manganese, iron, pesticides, herbicides, metals, minerals, salts, and more.
Crystal Quest Portable Reverse Osmosis System
In our opinion, the Crystal Quest Portable Reverse Osmosis System is the best budget countertop RO unit. This system costs less than $200 – that’s almost a quarter of the price of our top pick on this list, the RKIN U1. Don’t think you have to compromise on value if you spend less, though – this system has a respectable 50 GPD delivery rate and a massive 10 stages of filtration.
|Production Rate||50 GPD|
|Holding Capacity||0.30 gallon|
To help keep its cost budget-friendly, the Crystal Quest RO system doesn’t have a sleek, modern, expensive-looking unit to house the filters. Instead, the two filter cartridges are stacked one on top of the other and are simply placed horizontally on your countertop. Rather than having a dispenser for purified water, the unit comes with a dedicated faucet, so it makes sense to install it at your kitchen sink.
The system is the cheapest of its kind we’ve found upfront, with a starting cost of just $200. There’s the option to tack on additional filtration cartridges, including nitrate, arsenic, fluoride, and mineralization filters. We recommend going for the mineralizer filter for an extra $70 if you want to remineralize your RO water. The unit is also one of the cheapest to run and maintain, costing approximately $70-$90 per year.
People who want to spend the least amount of money on a countertop RO filter system that won’t let them down.
What We Like:
- The most affordable option on this list
- 10 thorough stages of purification
- Doesn’t need electricity
- No tanks to fill or empty
What We Don’t Like:
- Very slow water flow
- No performance certification
10-Stage Water Purification
Performance-wise, the Crystal Quest RO system is as thorough as it gets with 10 stages of purification. The granular activated carbon filter removes chlorine, VOCs, and pesticides; the reverse osmosis membrane eliminates the majority of TDS; a copper-zinc oxidation media removes lead, chromium and arsenic and prevents the growth of bacteria; the ion exchange resin tackles hard water minerals; and the final GAC post-filter gets rid of lingering tastes and odors. We couldn’t find any information about the RO membrane’s efficiency ratio, and as far as we can tell, the unit isn’t performance certified for its contaminant removal abilities.
When it comes to flow rate, the unit provides just 0.02 gallons of water per minute on demand (in comparison, most faucet filters have a 2 GPM flow rate), so there’s no denying that it’s a slow-and-steady purification solution. The manufacturer recommends the unit for “emergency water filtration or individual consumption”, so make sure to manage your expectations if you plan to use it as a long-term solution for your family. A good idea is to batch-fill one or several pitchers or containers, so you have fast access to filtered water throughout the day whenever you might need it.
A benefit of this countertop unit is that you don’t have to fill any tanks because the filters are connected via flexible tubing to your faucet. That means water from your faucet will flow through the filters before exiting the RO faucet. It also means the unit doesn’t use an electric pump or run off electricity, so you can take it with you to anywhere with a drinking water faucet.
📚 Methodology: How We Tested The Best Countertop RO Systems
When we tested, reviewed, and shortlisted the systems in this guide, we made several important considerations – which we suggest that you make too, to help you find the best RO unit for your situation.
- Water source – First, we considered our water source, and what we wanted to remove, when choosing a countertop reverse osmosis system. Reverse osmosis removes the great majority of contaminants from water, but some contaminants, such as hydrogen sulfide, some pesticides, herbicides, and some VOCs may slip through the RO membranes of even the best countertop water filter systems. We recommend testing your water if you haven’t already, which will help you determine which contaminants you want to remove. From there, you can check that your chosen RO system has been tested to remove these impurities.
- Filtration process: Our research into the RO process told us that it typically involves the same few filtration stages to purify water: a sediment pre-filter (which removes sediment, like sand, dust and rust), an activated or granular carbon filter (which uses adsorption to reduce chlorine, chemicals, bad taste and odor), a reverse osmosis membrane (which removes up to 99.9% of all total dissolved solids), and a second carbon filter (which removes lingering impurities). Some of the systems that we reviewed offered additional treatment stages, including hydrogen infusion and UV purification. We considered the comprehensiveness of the filtration process when deciding on which systems to shortlist in this guide.
- Efficiency ratio – The nature of the reverse osmosis process is that as water is produced, water is wasted. We knew that traditional RO systems have a 1:4 ratio, which means that for every 1 gallon of water purified, 4 gallons of wastewater are produced. Countertop RO systems are thankfully more efficient, and when selecting the systems for this guide, we only considered those with a pure-to-waste ratio of at least 1:1, meaning that 1 gallon of water is wasted for every 1 gallon produced. Some of the best systems we reviewed had efficiency ratios of 3:1, 4:1, or even 5:1, which means far less water waste to contend with.
- Water production rate – RO systems have a water production rate that’s measured in GPD, or gallons per day. A good water production rate will keep things moving quickly through your system, allowing for faster access to clean drinking water. We looked for systems with a water production rate of around 75 GPD, which is the best we’ve seen for countertop RO units. However, we kept in mind that some systems stored water post-filtration before dispensing, so flow rate and dispensing speed were separate entities.
- Remineralization needs – Our very top recommended RO water filters designed for countertop use have alkaline remineralization filters. These reintroduce healthy minerals to your drinking water after filtration. If you prefer the taste and health benefits of mineral water, look for a filter that offers an optional remineralization stage.
- Storage capacity – Since most of the countertop reverse osmosis filters we reviewed don’t connect to a faucet, storage tank capacity was another important factor to consider. We wanted the capacity to be high enough that we could access a decent amount of water without constantly having to refill the unit. On average, the best systems we reviewed had a purified water storage capacity of around half a gallon.
- Filter lifespan – We knew that most folks wouldn’t want the hassle and expense of replacing multiple filters more often than necessary, so we looked for systems with long-lasting filters. On average, we found that the filters in the best countertop RO systems lasted 6-24 months, and most units had only 2 filters to replace – 3 at most.
- Unit size & design – With countertop RO systems being intended for countertop setup, we looked for units that had sleek, smart, and space-saving designs. We prioritized systems that had been thoughtfully designed to minimize their footprint, and we generally looked for modern units that would blend in nicely with other countertop appliances, like microwaves and coffee machines.
- Ease of installation & use: We think countertop RO systems are ideal for a homeowner who doesn’t want to deal with the hassle of cutting through their waterline to install a reverse osmosis filter. But they still require some maintenance that under-sink units don’t need: most countertop systems aren’t connected to your plumbing, so you’ll need to fill and empty the tanks yourself. When ranking the systems in this guide, we focused on those with digital display screens that made it easy to know when to top up the water, replace the filters, and dispense the right amount of water for your glass.
- Performance certifications or testing: Official certifications can provide peace of mind that a portable countertop reverse osmosis system has been tested and approved for its contaminant removal claims. The key certification for reverse osmosis filters is NSF/ANSI Standard 58. While an official certification wasn’t essential to us, we generally preferred for our selected systems to at least have third-party testing as proof of their contaminant removal abilities.
❔ Frequently Asked Questions
Are countertop reverse osmosis systems worth it?
Yes, countertop reverse osmosis systems are worth it for anyone who wants to benefit from the RO purification process without the hassle of an under-sink installation. If you’re willing to commit to maintenance (including filter changes every 6-24 months) and you want the very best water purification method, but you also want a system that’s easy to install and relatively portable, a countertop RO system is the answer.
What is the best countertop reverse osmosis system out there?
In our opinion, the best countertop RO system is the RKIN U1 because it offers more features than any other similar system, including a built-in remineralization filter, hydrogen water infusion, and the ability to dispense hot or cold purified water at your chosen temperature.
Do countertop reverse osmosis filters work?
Yes, countertop reverse osmosis filters work to remove up to 99.99% of all dissolved solids – just make sure to buy a system sold by a reputable manufacturer, and if you’re unsure, go for a unit that has been performance certified or at least has third-party test results to support the manufacturer’s performance claims.
Can reverse osmosis be portable?
Yes, reverse osmosis can be portable. Look for a countertop RO system, which just needs to be plugged into a power socket, making it possible to take it to work, vacation homes, and anywhere with access to an electricity supply.