The best countertop reverse osmosis systems are extremely high-performing and can reduce hundreds of impurities from water. They’re also highly efficient and waste less water than conventional RO systems, and are easy to install due to their plug-and-play designs.
We conduct our own hands-on testing to obtain the data we need to review and compare water filters. All the RO systems in this guide were personally tested by Brian, the founder of Water Filter Guru, WQA Certified Water Specialist (CWS), and Certified Water Treatment Representative (CWR), who has been testing and reviewing water filters for 10+ years.
AquaTru
Waterdrop N1
RKIN U1
Table of Contents
Our Testing & Selection Process
We test and rank the filters in our “best” guides using our own data-driven scoring system comprising 6 key scoring factors, made up of 9 sub-factors.
For our Best Countertop Reverse Osmosis System guide, we selected and shortlisted each of the filters based on the scores they obtained for their performance, design quality, value, and more.
Additionally, we compared the systems’ technologies, efficiency ratios, and water-holding capacities, though these are not scoring factors.
Whenever we can, we award our performance scores based on quantifiable data. But some categories – such as setup and design – benefit from our own subjective opinion.
To choose the best systems, we shortlisted the products that had the best overall scores, paying special attention to their contaminant reduction scores.
RO systems are high-end products and tend to be more expensive, but we still wanted to recommend a few different options to suit different budgets and preferences.
We excluded some water filters from this guide for a few reasons, including if they didn’t qualify as reverse osmosis systems (i.e. using a semi-permeable membrane to purify water) or they weren’t available within the USA.
We also ruled out systems that simply weren’t as good as their competitors. For instance, filters that did a poorer job at reducing contaminants, got poor scores for design, setup, and maintenance, were sold by a new or unreliable company, or were of poorer value overall, didn’t make the list.
Note: Our reviewing process takes time. We’re continuously trying and reviewing new RO systems, so if we haven’t yet reviewed a system, it’s probably on our list to try.
The 3 Best Countertop Reverse Osmosis Systems
| Product | AquaTru | Waterdrop N1 | RKIN U1 |
|---|---|---|---|
| Score | 9.59 | 9.17 | 8.83 |
| Price | $449.00+ | $299.00 | $749.95 |
| Certifications | NSF 42, 53, 58, 401, and P473 | – (Not specified) | NSF 58 (in progress) |
| Filter Capacity | 600 – 1,200 gallons | 550 – 1,600 gallons | 6, 12, 24 months |
| Cost per Gallon | $0.11/ gallon | $0.09/ gallon | $0.08/gallon |
| Warranty | Lifetime | 1 year | 1-year warranty & 1 year money-back guarantee |
| Read Review | AquaTru review | Waterdrop N1 review | RKIN U1 review |
AquaTru
The AquaTru is our top recommended countertop reverse osmosis system because it reduced more contaminants than any other RO system in our testing. It also got the best score overall because it did better than any other system across almost every performance category.
Best For
Product Specs
| Price | $449.00+ |
| Contaminants Reduced | 83+ |
| Certifications | NSF 42, 53, 58, 401, and P473 |
| Process | Mechanical + RO + Carbon |
| Production Rate | 600 – 1,200 gallons |
| Annual Cost | ~$100 |
| Warranty | Lifetime |
Why It’s Best
The AquaTru is the best overall countertop RO system because it did better than any other system we tested at reducing contaminants in our water.
Our post-filtration results showed that the AquaTru had reduced 100% of all the trace contaminants in our water, making it the only reverse osmosis unit we tested that purified our water completely.
It’s also the only countertop RO system to have obtained performance certifications for every single contaminant it’s claimed to reduce – and it has a better pure-to-wastewater ratio than any other system.
AquaTru Performance
The AquaTru scored a 9.59 for performance overall – one of the best scores we’ve ever awarded, and currently higher than any other countertop RO system has obtained.
For reducing health-related contaminants in our water, the unit received a score of 9.90. It eliminated 100% of all contaminants with possible health effects, including lead, strontium, uranium, fluoride, molybdenum, and barium. It also got a 9.90 score for aesthetic contaminants because it reduced 100% chlorine in our water.
A standout performance feature of the AquaTru is that it’s IAPMO certified to NSF Standards 42, 53, 58, 401, and P473 for the reduction of all 83 contaminants that AquaTru claims it can reduce. Many of its competitors aren’t certified at all, and others are only certified to reduce a handful of contaminants.
The system also got the best design score of any countertop RO unit we tested: 9.70. We had no complaints about its component quality, and its IAMPO performance certification also incorporates a materials safety certification. Even better, it has an NSF 372 certification for lead-free design.
AquaTru also did better than its competitors with its 4:1 recovery rate, meaning that only 1 gallon of water was wasted for every 4 gallons purified.
We awarded the system 10.00 and 9.75 scores for setup and maintenance. We didn’t have to prime the filters, and the unit arrived partially assembled. The display screen notified us whenever a filter needed replacing, and the unit’s ongoing cost of $0.11/ gallon was super affordable.
We think the AquaTru is the best countertop reverse osmosis system for folks who want a top-performing certified unit with the option for a remineralization upgrade.
| Criteria | Results |
|---|---|
| Overall Score | 9.59 |
| Health Related Contaminants | 9.90 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Certified for 100% of reduction claims |
| Filtration Rate | 0.08 GPM |
| Component Quality | Outstanding |
| Component Certification | Exceptional |
| Setup | Exceptional |
| Servicing Requirements | Outstanding |
| Costs | $0.11/ gallon |
| Warranty Length | 1 year |
| Shipping | Free shipping |
| Returns | 30 days |
Waterdrop N1
The Waterdrop N1 is a more affordable alternative to the AquaTru that performed very similarly in our testing. It reduced or removed 10+ contaminants in our water, including copper, lead, barium, nitrate, uranium, zinc, and strontium.
Best For
Product Specs
| Price | $299.00 |
| Contaminants Reduced | 90% of contaminants |
| Certifications | – (Not specified) |
| Process | PP Cotton + Carbon Block + RO Membrane |
| Filter Capacity | 550 – 1,600 gallons |
| Annual Cost | ~$70 |
| Warranty | 1 year |
Our Verdict
The Waterdrop N1 is our second-choice countertop reverse osmosis water filtration system, which you might prefer if your budget is a little smaller.
It wasn’t quite as high-performing as the AquaTru, but it still got great scores for contaminant reduction, design, setup, and maintenance.
The system eliminated 100% of most contaminants in our water, and we awarded it top scores for reducing health-harmful and aesthetic contaminants. Our only disappointment was that it doesn’t have a remineralization filter.
The N1’s efficiency ratio is 3:1, putting it just behind AquaTru (which has a 4:1 efficiency ratio).
Waterdrop N1 Performance
The Waterdrop N1 received a 9.51 score for contaminant reduction. In our testing, it reduced 100% barium, chlorine, copper, lead, molybdenum, nitrate, phosphorous, strontium, sulfate, uranium, and zinc.
It reduced just over 93% fluoride, which was good, but not as impressive as the RO systems that eliminated this contaminant.
The N1 isn’t performance-certified, which was the main reason why its overall contaminant reduction score was lower than AquaTru’s.
We awarded the unit a score of 8.10 for design. Again, it didn’t quite match up to AquaTru here because it doesn’t have a materials safety certification, which pulled its score down. But in terms of design, feel and quality, it was no different from the AquaTru. It has a majority plastic design, and the components that the water comes into contact with are made from BPA-free Polypropylene (PP).
Setup and maintenance were two performance categories in which the Waterdrop N1 excelled, receiving 9.50 and 10.00 scores for each. Like the AquaTru, the N1 is a plug-and-play machine that comes with the filters pre-installed. We just rinsed and flushed the system a few times following instructions in the manual.
Replacing the filters was easy and didn’t require any special knowledge. The N1 also has a screen that displays filter change reminders, and its ongoing cost is slightly lower than AquaTru’s at just $0.09/ gallon. A unique feature of this system that made maintenance easier was its internal UV light. This sterilizes the purified water holding tank, so it doesn’t have to be taken apart to be cleaned.
We recommend the Waterdrop N1 to anyone who wants a more affordable alternative to the AquaTru, with very similar contaminant reduction and efficiency data but no option to upgrade to a remineralization filter.
| Criteria | Results |
|---|---|
| Overall Score | 9.17 |
| Health Related Contaminants | 9.90 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified for any reduction claims |
| Filtration Rate | 0.1 GPM |
| Component Quality | Fair |
| Component Certification | Not certified |
| Setup | Outstanding |
| Servicing Requirements | Exceptional |
| Costs | $0.09/ gallon |
| Warranty Length | 1 year |
| Shipping | Free shipping to lower 48 |
| Returns | 30 days |
RKIN U1
The RKIN U1 is the most advanced, tech-forward RO system we’ve tested. It eliminated the majority of contaminants in our water and then delivered it at any temperature, hot or cold, at the press of a button. It’s also the only system on this list with a built-in remineralization filter.
Best For
Product Specs
| Price | $749.95 |
| Contaminants Reduced | 99% of most contaminants |
| Certifications | NSF 58 (in progress) |
| Process | Mechanical + Carbon + RO + Alkaline + Hydrogen infusion |
| Filter Capacity | 6, 12, 24 months |
| Annual Cost | ~$180 |
| Warranty | 1-year warranty & 1 year money-back guarantee |
Our Take
The RKIN U1 has the highest price point of any of the countertop filtration systems we’ve tried, but it also offers far more in terms of features and benefits. It’s the only system we tested that delivers hot and cold water, with temperature presets and the option to set your exact desired temperature, and it remineralizes water with a built-in filter.
The unit performed very similarly to AquaTru when reducing contaminants. But it got a slightly lower health-related contaminant score due to the addition of some substances.
RKIN U1 Performance
The RKIN U1 secured a 9.00 score for contaminant reduction. It eliminated 100% chlorine, copper, fluoride, lead, molybdenum, uranium, and zinc, and greatly reduced barium, nitrate, and sulfate.
But its overall score was impacted by the fact that strontium increased from 0.108 PPM to 2.42 PPM in our filtered water, most likely from the remineralization filter. The unit also lacks a performance certification.
The system got good scores in the setup and maintenance categories: 10.00 and 9.75 respectively. The U1 is also a plug-and-play system, and it has a flush function that you can activate by pressing a button, so we didn’t have to manually prime or flush the filters. Our estimated ongoing cost for the system was $0.0809/ gallon, making it the most affordable to maintain in the long run, despite having the highest upfront cost.
The U1’s filtration rate let it down slightly – it was just 0.07 GPM (AquaTru’s measured at 0.08 GPM, while the Waterdrop N1’s was better at 0.1 GPM). It also has a 1:1 efficiency ratio, so it’s not quite as efficient as the AquaTru or N1.
In the design category, we were pleased with the U1’s component quality, but it was lacking a materials safety certification.
In our opinion, the U1 is the best choice for folks who want the leading high-tech RO system with a host of perks and add-ons that are rarely found all in one unit. If you use a lot of hot water and want to purify it easily, the U1 makes sense for you.
| Criteria | Results |
|---|---|
| Overall Score | 8.86 |
| Health Related Contaminants | 9.30 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified for any reduction claims |
| Filtration Rate | 0.07 GPM |
| Component Quality | Outstanding |
| Component Certification | Not certified |
| Setup | Exceptional |
| Servicing Requirements | Exceptional |
| Costs | $0.08/gallon |
| Warranty Length | 1 year |
| Shipping | Free shipping on orders over $175 to lower 48 states |
| Returns | 30 days |
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