We’ve been testing and reviewing water treatment products for nearly a decade. We personally tested and selected the best water filters in 2025 using our objective and data-driven scoring system. We’ve organized our picks based on filter type, so you’ll find what you’re looking for easily.
AquaTru
Cloud RO
Springwell CF
Table of Contents
Our Testing & Selection Process
We test water filters using a bespoke performance analysis that helps us to get a comprehensive understanding of their abilities across the board.
For our Best Water Filters guide, we selected the filters that received the highest overall performance scores, demonstrating their superiority over the other filters tested by us.
Within our testing, we assess filters for their contaminant reduction abilities, design quality, filtration speed, setup and maintenance requirements, and company offerings (such as warranty and guarantee). We also considered their upfront price and factors that only applied to specific systems, such as efficiency ratio for reverse osmosis systems.
We use objective and quantifiable data wherever possible in our testing process. But for some testing categories, it’s only feasible for us to conduct our own subjective assessment, which is supported by data where possible.
You can see our complete testing and scoring process here.
To choose the best water filters, we compared the performance statistics for all the filters we’ve reviewed and examined their testing data side-by-side.
We selected the products with the highest scores, with a particular focus on the contaminant reduction category.
Each of the filters on this list is unique in its filtration processes, application, and outcomes. We’ve aimed to share reviews of a range of filter technologies, so there’s a high chance that we’ve tested a filter in the category you’re interested in (if we haven’t, let us know!).
We automatically excluded some products from this guide, including:
– Water softeners, systems exclusively designed for well water, and treatment devices that are used to alter the water’s composition but aren’t primarily used for filtration.
– Filters that are unavailable in the US or are repeatedly sold out.
– Systems with setbacks that outweighed their advantages, or those that simply didn’t match up to their competitors across most performance categories.
The Best Water Filters of 2025
| Product | AquaTru | Cloud RO | SpringWell CF |  Waterdrop G3 P800 |  Clearly Filtered Under Sink |  Waterdrop King Tank |  Epic Pure |  Weddell |  Kind E-3000 |
|---|---|---|---|---|---|---|---|---|---|
| Score | 9.54 | 9.25 | 8.52 | 9.21 | 9.18 | 9.10 | 8.90 | 8.71 | 8.51 |
| Type | Countertop RO | Under-Sink RO | Whole House | Under-Sink RO | Under-Sink | Gravity | Gravity | Shower | Whole House |
| Price | $449+ | $749 | $1015 | $539 - $999 | $550 | $229+ | $70 | $90 | $1,798 |
| Certifications | NSF 42, 53, 58, 401, and P473 | NSF 58 | - | NSF/ANSI 53, 58, 372 | NSF 42, 372 | NSF 372 | - | NSF 177 | - |
| Filter Capacity | 600 – 1,200 gallons | 500 - 1,500 gallons | 1M gallons | 550/ 1100/ 2900 gallons | 2,000 gallons | 3,000 gallons | 150 gallons | 8,000 gallons | 80,000 gallons |
| Cost per Gallon | $0.11 | $0.26 | $0.0013 | $0.11 | $0.22 | $0.06 | $0.17 | $0.003 | $0.0018 |
| Warranty | 1 year | 1 year | Lifetime | 1 year | 2 years | 1 year | Lifetime | Lifetime | Limited Lifetime |
| Read Review | Aquatru review | Cloud RO Review | Springwell CF review | Waterdrop G3 RO review | Clearly Filtered under-sink review | Waterdrop King Tank review | Epic Pure review | Kind E-3000 review |
During our decade of using and reviewing water filters, we’ve seen demand for filtration solutions grow exponentially as public knowledge of the harmful contaminants in our drinking water continues to spread. We’re happy to see that the market is now bursting with options for a variety of situations.
Our top picks are sold by reputable, established water filter manufacturers like AquaTru, Clearly Filtered, and SpringWell, as well as newer, up-and-coming brands that are paving the way with revolutionary technology, like Cloud.
AquaTru
The AquaTru countertop RO system got the highest overall score of any water filter we’ve tested so far. It performed better than any other filter in our contaminant reduction testing, has performance certifications for every single contaminant that AquaTru claims it can remove, and impressed us with its super simple setup and durable design.
Best For
Anyone looking for the best-performing countertop reverse osmosis system that doesn’t require installation, is affordable to maintain, and certified for 100% of the manufacturer’s contaminant reduction claims.
What We Like
What We Don’t Like
Product Specs
| Price | $449.00+ |
| Contaminants Removed | 83+ |
| Certifications | NSF 42, 53, 58, 401, and P473 |
| Process | Mechanical + RO + Carbon |
| Filtration Capacity | 600 – 1,200 gallons |
| Annual Cost | ~$100 |
| Warranty | Lifetime |
We used the AquaTru Classic and Alkaline Classic RO systems to purify our city water in Colorado. The system comes in four configurations:
- The Classic model
- The Alkaline Classic with a remineralization filter
- The Classic Connect with connection to an app
- The Alkaline Connect, with both of these extra features.
In terms of costs, the system will set you back around $450 upfront, with the upgraded configurations adding $20-$70 to the price. This is on the lower end of the scale compared to the other countertop RO systems we’ve tested.
The AquaTru has a predominantly plastic design (it’s made from Tritan plastic, which is BPA- and BPS-free), with a robust construction and certifications for materials safety and structural integrity. It also holds an NSF 372 certification for lead-free design. It’s not the most high-tech or feature-heavy countertop RO system we’ve come across, but nor does it need to be.
Removed All Contaminants with Health Effects From Our Water
Right off the bat, our contaminant reduction testing for the AquaTru provided the best results of all the filters we’ve tested so far.
We used a lab testing service called Tap Score to test the system three times: once with the Classic VOC filter, and once with the Alkaline Remineralizing VOC filter, and once with the AquaTru Carafe.
When we tested the AquaTru Classic, the system removed 100% of all the trace levels of 11 contaminants with possible health effects detected in our water, including the three contaminants detected at concentrations above the lab’s Health Guideline Level: fluoride, lead, and uranium. This contributed to its high contaminant reduction score of 9.91.
In our Alkaline Classic test, fluoride and uranium were also detected above the HGL, and the AquaTru removed these completely. Additionally, chloroform (a disinfection byproduct) was detected in our unfiltered water, and once again, the AquaTru removed it down to 0.
| Contaminant | Measurement | Pre-Filtration | Post-Filtration | % Change |
|---|---|---|---|---|
| Total THMs | μg/L | 2.08 | 0 | -100.00% |
| Chloroform | μg/L | 2.08 | 0 | -100.00% |
| Chloride | mg/L | 28.5 | 0 | -100.00% |
| Sulfate | mg/L | 8 | 0 | -100.00% |
| Nitrate (as N) | mg/L | 4.2 | 0 | -100.00% |
| Fluoride | mg/L | 0.9 | 0 | -100.00% |
| Molybdenum | mg/L | 0.0019 | 0 | -100.00% |
| Copper | mg/L | 0.31 | 0 | -100.00% |
| Barium | mg/L | 0.0228 | 0 | -100.00% |
| Strontium | mg/L | 0.135 | 0 | -100.00% |
| Uranium | mg/L | 0.0096 | 0 | -100.00% |
| Potassium | mg/L | 0 | 1.1 | n/a |
| Carbonate | mg/L | 0.08 | 14.3 | 17775.00% |
| Sodium | mg/L | 11.2 | 1.67 | -85.09% |
| Bicarbonate | mg/L | 82.75 | 6.18 | -92.53% |
| Magnesium | mg/L | 7.32 | 9.78 | 33.61% |
| Calcium | mg/L | 30.5 | 0.9 | -97.05% |
| Total Dissolved Solids | mg/L | 164 | 71 | -56.71% |
| Hardness (Total) | mg/L | 106.96 | 42.52 | -60.25% |
That makes the AquaTru better-performing than any other filter we’ve tested, as it’s the only system so far that has completely eliminated all health-related contaminants in our water.
The only side-effect of the system’s extremely thorough reverse osmosis purification is that calcium, magnesium, and several other beneficial minerals and salts were also reduced in our water, even when we used the Alkaline Classic model with the remineralization filter. However, there were some differences in the data between the two tests:
In the initial test with the standard VOC filter, calcium in our water was reduced by 97%, magnesium by 94%, and chloride and sodium were both completely removed. The pH of our water actually increased slightly from 7.17 to 8.
In the second test with the alkaline remineralizing filter, calcium still decreased by 97.5%, but magnesium was only reduced by 33%. Additionally, the pH of our water increased significantly, from 7.3 to 10.7, which is seriously impressive. This shows that the remineralization filter was working as intended.
Certified to Reduce 100% of 82 Contaminants
The AquaTru has been IAPMO certified to NSF Standards 42, 53, 58, 401, and P473 for the removal of 83 contaminants, making it the only filter we have tested so far that can reduce 100% of all the contaminants in the manufacturer’s reduction claims.
Easy Setup & Maintenance
The AquaTru is a plug-and-play system, so it has one of the simplest setup processes of all the filters in this guide. We just had to set it up on our countertop, install the filters, wash and fill the tanks, and plug in the unit. We primed the filters by running tanks of water through the system. We awarded it a 10.00 in this category.
We found the system to be low-maintenance given that it uses multiple filtration stages. We had to periodically wash out the water tanks, clean the outside of the unit, and replace the three filters according to their individual schedules (every 6-24 months). The display screen indicates whenever a particular filter needs to be replaced.
The overall cost per gallon for the filters is $0.11/ gallon, which makes the AquaTru one of the cheaper-to-maintain systems we’ve tested, despite using multiple different filter stages. It received another high score in the maintenance category: 9.75.
The final point that we want to mention here is filtration speed. We timed the unit in our testing, and it purified 11 cups in 15 minutes and 53 seconds, giving it a flow rate of 0.04 GPM
The purified water gets stored in a gravity tank, ready for dispensing. We found that the flow of water exiting the tank was slow – and it only got slower as the tank emptied. This pulled the filtration rate score down to 7.00.
Read the full review here: AquaTru Review
Aquatru Carafe
The Carafe version uses the exact same filter technology, but filters the water into a glass vessel, rather than plastic. It also has a slightly smaller footprint.
| Criteria | Results |
|---|---|
| Health Related Contaminants | 9.90 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Certified for 100% of reduction claims |
| Filtration Rate | 0.04 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 |
Cloud RO
Cloud RO is the best-scoring under-sink reverse osmosis system we’ve reviewed so far. It also got the second-highest performance score, after the AquaTru, of all the systems we’ve tested. The unit removed up to 100% of all contaminants with health effects detected in our water. It’s also NSF certified and impressed us with its design quality and ease of maintenance.
Best For
Folks who like the idea of an under-sink RO filtration system that purifies water on demand, but without the excessive water waste and bulky design of a conventional under-counter unit.
What We Like
What We Don’t Like
Product Specs
| Price | $749 |
| Contaminants Reduced | 200+ |
| Certifications | NSF 58 |
| Process | Carbon + Reverse Osmosis + Remineralization |
| Filter Capacity | Pre/Post Filters 500 gallons, RO membrane 1,500 gallons |
| Annual Cost | ~$200 |
| Warranty | 1 year |
We tested Cloud RO (or Cloud, for short) to assess its ability to purify our municipal water in a townhome in Denver, Colorado. The unit is a conventional tank-based RO system, but with a modern twist.
It’s made from BPA-free food-grade plastic and comes with a lead-free, stainless steel faucet, a small 3.2-gallon water tank, and built-in sensors that track water consumption, tank volume, and water filter lifespan. It’s battery-powered, so no electricity connection is needed.
The system has a fairly high price tag at around $750, so it’s on the more expensive end for a point-of-use filter, but the price is fair for what you get.
Comprehensive RO Purification
Cloud RO is another reverse osmosis system, so, like the AquaTru, we expected it to purify our water (as opposed to just reducing specific contaminants).
Our unfiltered water contained a handful of contaminants with possible health effects, including fluoride and two types of disinfection byproducts (which were both detected above the HGL), aluminum, and copper.
Cloud RO reduced 100% of fluoride and both disinfection byproducts, aluminum, copper, manganese, molybdenum, and strontium, and greatly reduced barium (by 78%) and sulfate (by 94%).
So, it reduced all contaminants significantly, but it wasn’t quite as thorough as the AquaTru, giving it a slightly lower score of 9.42.
| Property | Type | Measurement | Pre-Filtration | Post-Filtration | % Reduction |
|---|---|---|---|---|---|
| Chloroform | Disinfection Byproducts | PPB | 8.22 | 0 | -100.00% |
| Total THMs | Disinfection Byproducts | PPB | 10.87 | 0 | -100.00% |
| Bromodichloromethane | Disinfection Byproducts | PPB | 2.65 | 0 | -100.00% |
| Fluoride | Inorganics | PPM | 0.6 | 0 | -100.00% |
| Sulfate | Inorganics | PPM | 20 | 1.1 | -94.50% |
| Chloride | Inorganics | PPM | 15 | 1 | -93.33% |
| Aluminum | Metals | PPM | 0.164 | 0 | -100.00% |
| Barium | Metals | PPM | 0.0264 | 0.0057 | -78.41% |
| Copper | Metals | PPM | 0.0099 | 0 | -100.00% |
| Manganese | Metals | PPM | 0.0016 | 0 | -100.00% |
| Molybdenum | Metals | PPM | 0.002 | 0 | -100.00% |
| Strontium | Metals | PPM | 0.097 | 0 | -100.00% |
| Zinc | Metals | PPM | 0 | 0.024 | #DIV/0! |
| Bicarbonate | Minerals | PPM | 62.98 | 10.36 | -83.55% |
| Calcium | Minerals | PPM | 18.1 | 1.2 | -93.37% |
| Carbonate | Minerals | PPM | 0.729 | 2.39 | 227.85% |
| Magnesium | Minerals | PPM | 3.4 | 1.53 | -55.00% |
| Potassium | Minerals | PPM | 1.03 | 0 | -100.00% |
| Sodium | Minerals | PPM | 15.3 | 1.44 | -90.59% |
| Hardness (Total) | Properties | PPM | 59.95 | 9.34 | -84.42% |
| pH | Properties | 8.4 | 9.7 | 15.48% | |
| Total Dissolved Solids | Properties | PPM | 76 | 14 | -81.58% |
The system has a built-in remineralization filter, rather than this being an optional upgrade, which increased the pH of our water from 8.4 to 9.7.
Calcium in our water was reduced by 93%, magnesium by 55%, potassium by 100%, and sodium by 90%. Without the remineralization filter to reintroduce minerals, these reduction rates would likely have been higher.
NSF Certified for TDS Reduction
Another benefit that Cloud RO shares with AquaTru is an official performance certification, although Cloud’s isn’t as impressive: it holds an NSF 58 certification for TDS reduction. While a TDS reduction certification is a good start, we’d like to see the manufacturer obtain certifications for the system’s ability to reduce contaminants with health effects.
Cloud also has a materials safety certification as a component of its NSF 58 performance certification.
Challenging Install But Easy to Maintain
One of the biggest setbacks of any under-sink reverse osmosis system is the challenging installation process required.
Cloud has a simplified design: all filters are contained within a single box, and the base is detachable from the main unit body, so you can install the base alone without having to work around the bulk of the filter unit. This reduces unnecessary maintenance tasks, but we still had to connect the system to our water line, drill into our countertop to install the dedicated faucet, and install the drain line. It received a setup score of 7.50 for that reason.
We found the installation process fairly logical, and the instructions were helpful. But the process was time-consuming, and you’ll need some basic DIY and plumbing skills to avoid making mistakes.
Beyond the installation, Cloud is refreshingly easy and affordable to maintain, and we awarded it the top score of 10.00 in this category.
We downloaded the Cloud app, which displays helpful data on the system’s filter and battery status, as well as a TDS reading (if the TDS is higher than optimal, one or several of the filters need to be replaced).
Alongside replacing the filters, we also had to replace the unit’s battery, which lasts 1.5+ years. The manufacturer sends out a new battery pack with the replacement RO membrane.
The ongoing spend for Cloud RO works out at around $0.26/ gallon. That makes it over twice the spend of AquaTru, but it’s still very affordable to maintain.
Purified Water On Demand
When it comes to accessing purified water, Cloud has the edge over AquaTru, and it received a higher score (8.50) in the filtration rate category.
When you turn on the faucet, water is pumped straight from the RO tank. The filtration rate for the system is 80 GPD which gave us quicker access to water in our testing.
The system has an efficiency ratio of 1:1, so it’s not on par with AquaTru here, but it’s still better than the average pure-to-wastewater ratio of 1:4 (for every 1 gallon purified, 4 gallons are wasted).
Read the full review: Cloud RO Review
| Criteria | Results |
|---|---|
| Overall Score | 9.42 |
| Health Related Contaminants | 99 |
| Aesthetic Related Contaminants | 35 |
| Performance Certification | Certified for 16% of reduction claims |
| Filtration Rate | 80 GPD |
| Component Quality | Exceptional |
| Component Certification | Certified |
| Setup | Below Average |
| Servicing Requirements | Exceptional |
| Costs | $0.26/ gallon |
| Warranty Length | 1 year |
| Shipping | Free on all orders in the US |
| Returns | 12 month guarantee |
Springwell CF
The SpringWell CF is the highest-scoring whole-house water filter we’ve tested so far. This tank-based system has a high media capacity of up to 1,000,000 gallons and reduced more than 20 contaminants in our water.
Best For
People looking to filter their entire home’s water supply with a low-maintenance, dependable whole-house water filter system.
What We Like
What We Don’t Like
Product Specs
| Price | $1015+ |
| Contaminants Reduced | 10+ |
| Certifications | Not certified |
| Process | KDF + Catalytic Carbon |
| Filter Capacity | 1,000,000 gallons |
| Annual Cost | ~$40 |
| Warranty | Lifetime |
We tested the SpringWell CF in our 2-bathroom home in Arvada, Colorado. The system consists of a large tank that contains the KDF and coconut catalytic carbon media, and a separate 5-micron sediment filter.
The CF is priced at just over $1,000. Compared to similar units, it’s not the most affordable, but it’s not unusually expensive, either. Tank-based POE systems like this one are up to twice the price of whole-house cartridge filters because of the longevity of their filtration media.
Reduced 15 Contaminants with Health Effects
Our Tap Score test for the CF detected 15 contaminants with health effects in our unfiltered water. Lead, nickel, and two disinfection byproducts (chloroform and bromodichloromethane) were the most concerning to us because they were detected above the lab’s HGL.
The SpringWell CF eliminated six of these contaminants, including the disinfection byproducts. Our filtered water test results also showed a 96% reduction in lead.
We believe some of the lead contamination was coming from the home’s plumbing system post-filtration. So, if you suspect you have lead in your house, we’d recommend additional point of use treatment.
| Contaminant | Measurement | Pre-Filtration | Post-Filtration | % Change |
|---|---|---|---|---|
| Barium | PPM | 0.0267 | 0.0158 | -41% |
| Bromodichloromethane | PPB | 0.00832 | 0 | -100% |
| Chloroform | PPB | 0.0208 | 0 | -100% |
| Cobalt | PPM | 0.0011 | 0 | -100% |
| Copper | PPM | 0.222 | 0.0532 | -76% |
| Fluoride | PPM | 0.6 | 0.5 | -17% |
| Lead | PPM | 0.0182 | 0.0007 | -96% |
| Manganese | PPM | 0.002 | 0.0013 | -35% |
| Molybdenum | PPM | 0.0016 | 0 | -100% |
| Nickel | PPM | 0.0125 | 0 | -100% |
| Strontium | PPM | 0.125 | 0.09 | -28% |
| Sulfate | PPM | 36 | 27.2 | -24% |
| Total THMs | PPB | 0.02912 | 0 | -100% |
| Zinc | PPM | 0.917 | 0.255 | -72% |
The CF removed nickel and cobalt completely, and reduced copper (a plumbing-related contaminant) by 76%, zinc by 72%, and barium by 41%. It only reduced fluoride by 17%, but it doesn’t contain filtration media that targets this mineral, and it’s not marketed for this purpose.
While the CF didn’t purify our water like our top-pick RO systems, it still did a great job of reducing or removing most of the contaminants we were concerned about, earning it a respectable score of 8.31 in this category.
Our only disappointment was that it isn’t currently performance-certified, so it’s behind the AquaTru and Cloud systems in this respect.
Fast Filtration Rate
The SpringWell CF is available in three sizes, with three different flow rates:
- The 9 GPM SpringWell CF1 Whole House Water Filter – for 1-3 bathrooms
- The 12 GPM SpringWell CF4 Whole House Filter System – for 4-6 bathrooms
- The 20 GPM SpingWell CF+ Whole House Water Filtration System – for commercial use
We tested the SpringWell CF1, with a flow rate of 9 GPM, and we noticed no change in our flow rate or water pressure once it was installed. This is particularly important in a point-of-entry system as a reduction in water pressure could have affected the performance and efficiency of our home’s appliances and fixtures.
The CF’s great flow rate awarded it the top score of 10.00 in this category.
High Filter Media Capacity
The SpringWell CF comes with a pre-loaded media inside the tank. As a point-of-entry system, installing the CF requires some plumbing knowledge and confidence, and we chose to get it installed by a professional.
The process took around 2 hours and required re-routing our plumbing to a room where the filter would fit (an issue that was specific to our situation). Also, our plumber had to buy some additional parts for the job. This more challenging install resulted in a lower score for the system in this category: 7.00.
But once the system was installed, maintenance was easy and affordable because the filtration media has a capacity of 1,000,000 gallons, which equates to 3-5 years. Only the sediment filter needs replacing every 6-9 months, making this one of the lowest-maintenance water filters we’ve tested.
Plus, the CF’s ongoing cost came in at just $0.0013/ gallon, making it substantially more affordable than most of the smaller point-of-use filters we tested. The unit received one of the highest maintenance scores we’ve ever awarded: 9.75.
Read the full review: SpringWell CF Review
| Criteria | Results |
|---|---|
| Overall Score | 8.52 |
| Health Related Contaminants | 8.50 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified for any reduction claims |
| Filtration Rate | 9, 12, 20 GPM |
| Component Quality | Exceptional |
| Component Certification | Not certified |
| Setup | Weak |
| Servicing Requirements | Outstanding |
| Costs | $0.0013/ gallon |
| Warranty Length | Lifetime |
| Shipping | Free on orders over $29.99 in the continental US |
| Returns | 6 months with return shipping and 25% restocking fee |
Waterdrop G3 P800
Of all the tankless RO systems we’ve tested, the Waterdrop G3 P800 offered the best all-round performance. It has a fast filtration rate, a high-tech design, and simple maintenance requirements, and eliminated most of the impurities in our water.
Best For
Anyone looking for the best under-sink RO filtration system for a small under-sink space, or folks who simply prefer the convenience of a tankless unit.
What We Like
What We Don’t Like
Product Specs
| Price | $539 – $999 |
| Contaminants Removed | 1,000+ |
| Certifications | NSF/ANSI 58, 372 |
| Process | RO |
| Filtration Capacity | 550/ 1100/ 2900 gallons |
| Annual Cost | ~$145 |
| Warranty | 1 year |
We used the Waterdrop G3 P800 to purify city water in Parker, Colorado. The system is a smart take on the conventional under-sink reverse osmosis system, with a space-saving design thanks to its lack of a tank (water is pumped straight through the system to the faucet).
There are TDS meters on the smart faucet and the unit body and a filter life tracker, so we could check the filter performance and know exactly when to replace the filters.
The unit comes with a UV purifier (with a 99.9% sterilization rate), protecting against the potential for bacteria growth within the system. We were slightly disappointed that, unlike Cloud, it doesn’t have a built-in remineralization filter – Waterdrop sells one that needs to be installed separately and costs an extra $30.
The G3 P800 is one of the most expensive POU systems we’ve tested, costing just under $1,100. Waterdrop is a high-end brand known for the high prices of its RO systems, and this G3 model is costlier than similar units because of its tankless design.
Purified Our Drinking Water
The Waterdrop G3 P800 is a reverse osmosis system, and its contaminant reduction performance was comparable to AquaTru’s and Cloud’s.
The system eliminated 6 out of 9 of the contaminants with potential health effects detected in our unfiltered water, including arsenic and lead, which were detected at concentrations above the HGL.
Strontium, barium, and nitrate were also greatly reduced down to trace amounts.
The system also reduced the calcium and magnesium minerals in our water by 87%, and the pH reading dropped from 7.3 to 6.3.
This low pH meant the overall contaminant reduction score (9.28) was lower than it probably would have been if we’d installed the separate remineralization filter.
| Contaminant | Measurement | Pre-Install | Post-Install | % Change |
|---|---|---|---|---|
| Total Dissolved Solids | PPM | 84 | 15 | -82.14% |
| Arsenic | PPM | 0.0029 | 0 | -100.00% |
| Barium | PPM | 0.0283 | 0.0033 | -88.34% |
| Calcium | PPM | 20.2 | 2.6 | -87.13% |
| Chloride | PPM | 2.2 | 0 | -100.00% |
| Copper | PPM | 0.203 | 0 | -100.00% |
| Fluoride | PPM | 0.3 | 0 | -100.00% |
| Lead | PPM | 0.0008 | 0 | -100.00% |
| Magnesium | PPM | 2.13 | 0.27 | -87.32% |
| Manganese | PPM | 0.0048 | 0 | -100.00% |
| Nitrate (as N) | PPM | 1.1 | 0.1 | -90.91% |
| Potassium | PPM | 2.12 | 0 | -100.00% |
| Selenium | PPM | 0.0015 | 0 | -100.00% |
| Sodium | PPM | 9.33 | 1.65 | -82.32% |
| Strontium | PPM | 0.199 | 0.025 | -87.44% |
| Sulfate | PPM | 7.8 | 0 | -100.00% |
IAPMO Performance Certified
The G3 P800 has been IAPMO certified to NSF 42, for removing chlorine, and NSF 58 and NSF 53, for reducing TDS, fluoride, cadmium, hexavalent chromium, and selenium.
That’s a big advantage of this system for folks who are keen to buy a tankless RO system with extensive proof of performance. While it’s not certified to reduce as many contaminants as AquaTru, it does better than Cloud in this category.
800 GPD Filtration Rate
The Waterdrop G3 P800 received a score of 10.00 from us in the filtration rate category. Its 800 GPD filtration rate is much higher than you’d actually need, meaning that you can be pretty certain of its ability to deliver purified water almost instantly.
The tankless design means water flows straight through the filters to the faucet, so a fast flow rate is particularly important.
The unit has a 3:1 pure-to-wastewater ratio, meaning for every 3 gallons purified, only 1 gallon of water is lost. This isn’t far behind AquaTru’s 4:1 efficiency ratio, and it’s particularly impressive given that the G3 offers on-demand under-sink filtration.
Note: Tankless RO units are susceptible to TDS creep, which can temporarily increase the TDS in purified water and reduce the water output, affecting the system’s performance efficiency. You can learn more about TDS creep in our guide.
Our Setup & Maintenance Experience
We awarded the G3 P800 a lower score of 7.00 for setup, and this was primarily because of the challenge of installing the drain line and dedicated faucet. Unlike Cloud, we didn’t have to worry about installing a tank, but the process still took us around 1 hour 30 minutes from start to finish.
But when it came to maintenance, the G3 was another RO system to surprise us with its ease and affordability of filter changes, awarding it a 10.00 score in this category. The built-in filter change reminder meant we didn’t have to make our own reminders for replacing the three filters, and we calculated the unit’s ongoing spend without the remineralization filter at just $0.11/ gallon. With the remineralization filter, its cost per gallon is $0.13/ gallon.
Read the full review: Waterdrop G3 P800 Review
| Criteria | Results |
|---|---|
| Health Related Contaminants | 9.50 |
| Aesthetic Related Contaminants | 3.50 |
| Performance Certification | Certified for 100% of reduction claims |
| Filtration Rate | 600 or 800 GPD |
| Component Quality | Outstanding |
| Component Certification | Certified |
| Setup | Weak |
| Servicing Requirements | Exceptional |
| Costs | $0.11/ gallon (w/o remineralization), $0.13/ gallon (w/ remineralization) |
| Company | Good |
Clearly Filtered Under Sink
The Clearly Filtered Under Sink system was the highest-scoring non-RO under-sink filter of all the systems we have tested so far, and has a much more DIY-friendly install than the RO models.
Best For
People wanting to filter their tap water with one of the top-performing direct-connect under-sink systems, without the difficult installation and mineral loss of an RO unit.
What We Like
What We Don’t Like
Product Specs
| Price | $550.00 |
| Contaminants Reduced | 232+ |
| Certifications | NSF 42, 372 |
| Process | Carbon + Ion Exchange |
| Filter Capacity | 2,000 gallons |
| Annual Cost | ~$440 |
| Warranty | Lifetime |
We tested the Clearly Filtered 3-Stage Under the Sink System on a shared, treated well water supply in Colorado. The system consists of three separate filter cartridges that are mounted together on a single housing.
It doesn’t offer the high-tech features of our top-pick reverse osmosis systems, like filter lifespan trackers and TDS readers, but its simplistic design is one of the reasons why it’s more affordable.
The upfront price is around $550, which is steep for a non-RO system, but its contaminant reduction performance is also much more comprehensive than for similar units (it’s tested to remove up to 99.99% of 232+ contaminants).
Reduced Uranium, Fluoride, & More
When we tested the Clearly Filtered Under-Sink system, 10 contaminants with possible health effects were detected in our unfiltered water, including uranium, chloroform, fluoride, and copper, which were detected at concentrations above the Tap Score HGL.
The unit did a great job at eliminating the first four of these contaminants, and reducing copper by 99.39%. It also removed 100% of barium and strontium, but it only reduced 23% nitrate, 5.6% molybdenum, and 21.25% sulfate. But Clearly Filtered doesn’t claim to reduce these contaminants.
There were a couple of interesting outcomes: sodium increased by 107% and potassium by over 1,000%, while calcium decreased by 92% and magnesium by 6%.
We think this is because one of the filter cartridges contains a combined sodium and potassium-loaded ion exchange resin, which exchanges these ions with minerals like calcium, magnesium, and uranium.
WQA Performance Certified
The Clearly Filtered Under-Sink system also has a WQA performance certification to NSF/ANSI Standard 42, for the reduction of chlorine, tastes, and odors.
But given that Clearly Filtered says it can reduce 232+ contaminants, we’d like to see them obtain additional certifications for contaminants with health effects, like lead and arsenic.
The system obtained a score of 8.98 overall for contaminant reduction.
Easy to Install & Use
We awarded the Clearly Filtered Under-Sink filter a setup score of 9.5 based on its quick and easy installation process. It has only a few parts, no drain line, and no dedicated faucet. The whole process took us 15 minutes from start to finish.
We just shut off our under-sink water supply, disconnected our cold water line from the cold water valve, and connected the inlet and outlet hoses. We then flushed the system by leaving the faucet on for 3-5 minutes.
Once set up, we measured the filter’s flow rate by timing how long it took to fill a glass. We filtered 2 cups of water in 7.47 seconds, which is equal to a flow rate of 1.01 GPM – so around half the speed that you’d usually get from your kitchen faucet. We thought this was pretty good for an under-sink filtration system, although not the fastest we’ve ever come across.
In terms of its servicing requirements, three of the system’s filters have the same lifespan, so we had the convenience of being able to change them at the same time. The filter maintenance cost was affordable at around $0.22 per gallon.
Read the full review: Clearly Filtered Under Sink Review
| Criteria | Results |
|---|---|
| Overall Score | 8.79 |
| Health Related Contaminants | 95 |
| Aesthetic Related Contaminants | 99 |
| Performance Certification | Certified for <1% of reduction claims |
| Filtration Rate | 1.08 GPM |
| Component Quality | Outstanding |
| Component Certification | Certified |
| Setup | Outstanding |
| Servicing Requirements | Outstanding |
| Costs | $0.22/ gallon |
| Warranty Length | 2 years |
| Shipping | Free shipping, all orders to all states |
| Returns | 30 days |
Waterdrop King Tank
We’ve tested the majority of popular gravity-fed water filters on the market, and the Waterdrop King Tank received the best overall score for its performance. The system also has the best contaminant reduction score of all stainless steel countertop systems we’ve used, and doesn’t use electricity or require a plumbing connection.
Best For
Folks who want a portable, high-capacity, no-install filtration system with the ability to reduce dozens of common contaminants with long-lasting filters.
What We Like
What We Don’t Like
Product Specs
| Price | $229+ |
| Contaminants Removed | 10+ |
| Certifications | NSF/ANSI 372 |
| Process | Carbon + Ion Exchange |
| Filter Capacity | 3,000 gallons |
| Annual Cost | ~$60 |
| Warranty | 1 year |
We tested the Waterdrop King Tank with a municipal water supply in Colorado. The system has the conventional “Berkey-style” stainless steel cylindrical design, and we awarded it a 9.40 score in this category.
Unlike many of its competitors, it uses a steel/glass sight spigot rather than plastic and is IAPMO certified to NSF 372 for lead-free design.
The King Tank has a more affordable price point than many of the other POU filters on this list, costing around $250. That’s a fair price given its long filter lifespan and its large 2.25-gallon water-holding capacity.
Thoroughly Filtered Our Water
We awarded the Waterdrop King Tank a 9.51 score for contaminant reduction. It eliminated the majority of contaminants with health effects in our water, including aluminum, chloroform, manganese, total THMs, and lead.
It also reduced 100% chlorine, 93% copper, 40% barium, and 28% sulfate.
The King Tank has separate fluoride filters that are included with the purchase, and it reduced 100% fluoride in our testing.
The only disappointment here is that the King Tank is the first on this list so far that hasn’t been performance-certified. Given that it did a great job of removing contaminants from our water, we think Waterdrop is underselling the King Tank by failing to provide this information.
Tricky Setup But Long-Lasting Filters
The Waterdrop King Tank got a lower score of 6.50 for setup, and that was because of the filter priming process: we found it time-consuming and tedious.
Getting a seal with the tan priming washer on our faucet was almost impossible, and the blue priming nipple only works with older faucets. You won’t be able to use either priming method if you have a modern faucet, like a spray or pullout faucet.
It took us over an hour to prime all 4 filters, plus 20 minutes to set up the body of the unit.
Thankfully, the filters have a long lifespan, and our ongoing cost per gallon for all the filters in the system was $0.06/gallon.
Read the full review: Waterdrop King Tank Review
| Criteria | Results |
|---|---|
| Health Related Contaminants | 9.90 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified |
| Filtration Rate | 4 GPH |
| Component Quality | Excellent |
| Component Certification | NSF/ANSI 372 |
| Setup | Failing |
| Servicing Requirements | Weak |
| Costs | $0.06/gallon |
| Company | Good |
Epic Pure
The Epic Pure pitcher got the best contaminant reduction score and overall performance score out of all the water filter pitchers we tested, making it our top recommendation for folks interested in this affordable, low-commitment method of filtration.
Best For
Anyone looking for an affordable, portable filtration solution that’s easy to set up and maintain.
What We Like
What We Don’t Like
Product Specs
| Price | $70.00 |
| Contaminants Reduced | 200+ |
| Certifications | Not certified |
| Process | Solid Activated Carbon Block |
| Filter Capacity | 150 gallons |
| Annual Cost | ~$150 |
| Warranty | Lifetime |
We used the Epic Pure pitcher to filter a treated, shared well water supply in Colorado. The pitcher holds 10 cups of water and has a much smaller footprint than the best countertop gravity system on this list, so it’s a good option for homes with limited counterspace.
If you do want a bigger filtered water holding capacity, the same filter can be used in the Epic Pure dispenser—we’ve tested this too; it holds around 1.75 gallons of filtered water and is essentially a larger, rectangular version of the pitcher with no handle.
The pitcher costs just under $70, or around $63 if you sign up to receive replacement filters on schedule, so it’s a great solution for folks who want to protect their families from common drinking water contaminants but can’t (or don’t want to) spend hundreds of dollars upfront.
Removed Contaminants More Effectively than Any Other Pitcher
We awarded the Epic Pure a 9.30 for reducing health-related contaminants in our water.
Specifically, the filter reduced 100% uranium, copper, and phosphorous, as well as 92% sulfate, 57% molybdenum, 41% barium, 27% fluoride, and 20% nitrate.
The system also reduced 100% chlorine in our water, awarding it a 9.90 for improving our water’s aesthetics.
Unfortunately, though, the filter isn’t currently performance-certified, which meant its overall contaminant reduction score was slightly reduced to 9.00.
Low-Hassle Setup & Maintenance
The Epic Pure was also quick and easy to set up and maintain and received scores of 9.50 in both categories.
It took us only a few minutes to wash and assemble the pitcher, and the filter didn’t need priming. We just filtered and discarded the first two pitchers of water.
As for maintenance, there’s just one filter to replace, and hopefully, the pitcher has an LED countdown timer that guided us on when to buy new filters.
The 150-gallon water filtration capacity is one of the best we’ve seen for a pitcher, although we did have to replace the filter more often than with many of the other systems we tested (once every 3-4 months on average). This meant our calculated ongoing maintenance cost was slightly higher at $0.31/ gallon.
Slow-and-Steady Gravity Filtration
The Epic Pure filtered 0.453 gallons of water in 12 minutes and 13 seconds, which gave it a filtration rate of 2.23 GPH.
This was pretty much exactly the same as the other water filter pitchers we’d tested, but it’s a gravity filter, so don’t expect to have filtered water instantly available.
Read the full review: Epic Pure Water Filter Pitcher Review
| Criteria | Results |
|---|---|
| Health Related Contaminants | 9.30 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified for any reduction claims |
| Filtration Rate | 2.23 GPH |
| Component Quality | Unsatisfactory |
| Component Certification | Not certified |
| Setup | Outstanding |
| Servicing Requirements | Outstanding |
| Costs | $0.31/gallon |
| Warranty Length | Lifetime |
| Shipping | Free shipping for the Clean Water Club only |
| Returns | Lifetime |
Weddell
The best shower filter we’ve tested so far is the Weddel Duo. This filter got good scores for its contaminant reduction and filtration rate and has an NSF 177 certification for reducing chlorine—something we rarely see for filters of this kind.
Best For
People who want a modern shower filter that uses a more thorough filtration process than many of its competitors and is certified for chlorine reduction.
What We Like
What We Don’t Like
Product Specs
| Price | $89.99 |
| Contaminants Reduced | 5+ |
| Certifications | NSF 177 |
| Process | Solid Activated Carbon Block |
| Filter Capacity | 8,000 gallons |
| Annual Cost | ~$25 |
| Warranty | Lifetime |
We installed the Weddell Duo on our bathroom shower that uses city water. It’s an inline filter, so it connects to your shower arm without replacing the showerhead.
There are two filters, one on each side of the unit, which has a clear and black/white plastic exterior.
The filter costs just under $90, so it’s one of the more expensive shower filters we’ve tested. But it’s also one of the only performance-certified shower filters we’ve used so far, so if proof of contaminant reduction is important to you, you might be happy to pay slightly more upfront.
Removed Chlorine, Disinfection Byproducts, & More
Before filtration, our shower water contained traces of three disinfection byproducts (chloroform, bromodichloromethane, and dibromochloromethane), as well as uranium, lead, and arsenic. These contaminants were all detected at concentrations above the Tap Score HGL.
Our water also contained chlorine, a chemical that’s commonly used for disinfection purposes and is one of the key contaminants that a shower filter is designed to remove. Several other metals, as well as fluoride, nitrate, and another disinfection byproduct were also detected at trace levels.
Our test results showed that the Weddell Duo filter effectively removed 100% chlorine and all disinfection byproducts, which was likely achieved by its solid carbon block filter (it’s the only shower filter we’ve tested to use this type of activated carbon).
It also removed 100% lead, but uranium and arsenic remained above the HGL. These contaminants require a different treatment process, and Weddell doesn’t claim that the Duo filter can remove them. But this affected the overall contaminant reduction score, bringing it down to 8.43.
As we mentioned, the Duo has an NSF certification to Standard 177 for chlorine reduction, but it hasn’t been certified to reduce any of the other contaminants claimed by the manufacturer (PFAS, microplastics, lead, and unpleasant odors).
Forward-Thinking Design Simplifies Installation & Maintenance
We awarded the Weddell Duo a score of 9.00 for setup, and this was largely thanks to its well-thought-out design. We were able to install it in less than five minutes with no tools, and it simply screws onto your existing shower arm, so it’s rental-friendly.
We had to flush the filter before it was ready to use, and this was easy: we just ran water from our shower for three minutes.
And on the subject of running water, we measured a flow rate of 1.43 GPM from the Duo filters. This was unsurprising given that it’s one of the only shower units to use two filters, doubling the amount of resistance that water comes up against. The average water-saving showerhead has a flow rate of 2 GPM.
Many of the shower filters we’ve tested required us to remove our showerhead and unscrew the filter unit to change the filter, but the Weddell Duo has a filter on either side of the unit. That meant we could unscrew the filter housings and replace the filters without touching our shower or uninstalling the entire unit.
Filters need replacing every 5-6 months or when you see a significant decrease in water pressure. Helpfully, the filter housings are clear, so we could also check for discoloration of filter number 1 (another sign that replacements are needed). The filters have a super low ongoing cost of $0.003/ gallon.
| Criteria | Results |
|---|---|
| Health Related Contaminants | 8.40 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Certified for 20% of reduction claims |
| Filtration Rate | 1.43 GPM |
| Component Quality | Excellent |
| Component Certification | Not certified |
| Setup | Excellent |
| Servicing Requirements | Excellent |
| Costs | $0.003/ gallon |
| Warranty Length | Lifetime |
| Shipping | Free shipping for lower 48 US states |
| Returns | 30 days, minus 10% restock fee |
Kind E-3000
The Kind E-3000 system received the best overall score of all the cartridge-based point-of-entry filtration units we’ve tested so far. We particularly had a good experience with its filtration rate and maintenance requirements.
Best For
Anyone who wants to filter their entire home’s water supply but with a more affordable option than the more expensive tank-based POE systems.
What We Like
What We Don’t Like
Product Specs
| Price | $1,998.00 |
| Contaminants Reduced | 160+ |
| Certifications | None |
| Process | Mechanical + Catalytic Carbon |
| Filter Capacity | 80,000 gallons |
| Annual Cost | ~$120 – $300 |
| Warranty | Limited Lifetime |
We tested the Kind E-3000 on municipal water in the mountains of Colorado. This simplistic, sturdy, two-cartridge system combines a long-lasting sediment pre-filter and catalytic carbon block filter.
It’s around 30% cheaper than the SpringWell CF (our top-recommended POE system overall) and should be the better option for folks who prefer to spend less money upfront. But it is more maintenance-heavy.
Highly Capable Cartridge Filtration
The Kind E-3000 Whole House Water Filter received an 8.23 score for contaminant reduction in our testing. Our water contained 12 contaminants with health effects, including chloroform and lead, which were present above the HGL.
In our initial test, the system reduced chloroform by 93.5%, but it only reduced lead by 58%. It also reduced fluoride, strontium, barium, and several other contaminants.
Unusually, 0.134 PPM of aluminum appeared in our filtered water, and copper levels increased by more than 100%.
We discovered that we’d tested the system with the filters in the wrong order, so we installed a new set of filters the right way around and repeated the test again.
This time, fluoride only decreased by 20%, nickel and zinc weren’t detected at all, lead was reduced entirely, strontium actually increased by 18%, and copper was almost completely removed (by 97%).
The filter uses solid carbon block media, which doesn’t produce carbon dust, so take it from us that you won’t get black flecks in your filtered water.
Kind hasn’t yet obtained a certification for the E-3000, so this further pulled down its overall contaminant reduction score.
Note: We’re reviewing the filter we tested here, which is the Kind E-3000. This system also contains a descaling TAC media cartridge, and we did notice a reduction in scale formation after installing it. If you don’t want to condition your water, you can buy the Kind E-1000, without the descaling cartridge, which is about $800 cheaper.
Fast Filtration Rate
The King E-3000 is available in just a single size, for homes with up to 6 bathrooms, with a fast 15 GPM flow rate. While the SpringWell CF costs more if you want a high-flow configuration, Kind offers this as their base model.
We noticed no interruptions to the flow rate in our faucets, showerheads, and appliances after installing this system.
DIY-Friendly Install And Maintenance
Whole-house water filters can often be tricky to install, especially if they’re tank-based.
The Kind E-3000 was more difficult to install than a POU system, which is why it received a 7.50 score in this category. But the unit was, at least, one of the easiest whole-house systems we’ve installed. It requires only two connections, and there are no fiddly parts and very little potential for making mistakes.
The installation took us 45 minutes to complete, followed by a 10-minute flush of the filters.
Maintenance is more of a hassle with cartridge-based systems compared to tank-based units like the SpringWell model. But the Kind system is still relatively low-maintenance, with a washable and reusable sediment pre-filter and a catalytic carbon filter lifespan of up to 80,000 gallons, or 1 year. The E-soft descaling cartridge never needs to be replaced.
The Kind E-3000 has one of the lowest ongoing costs of all the whole-house water filtration systems we’ve tested—just $0.0018 per gallon—so it did really well in the maintenance category, receiving a score of 9.50.
Read the full review: Kind E-1000 Review
| Criteria | Results |
|---|---|
| Overall Score | 8.51 |
| Health Related Contaminants | 8.40 |
| Aesthetic Related Contaminants | 9.90 |
| Performance Certification | Not certified |
| Filtration Rate | 15 GPM |
| Component Quality | Exceptional |
| Component Certification | Not certified |
| Setup | Below Average |
| Servicing Requirements | Excellent |
| Costs | $0.0018/ gal |
| Warranty Length | Limited Lifetime |
| Shipping | Free on orders over $99 |
| Returns | 120 days |