6 Best Gravity Water Filter Systems, Tested & Reviewed

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The best gravity water filters are portable, easy to set up and use in any location, and capable of reducing dozens of contaminants without the need for water pressure or electricity. 

We test and compare water filters using our own hands-on comprehensive assessment process, covering all areas of performance. 

I’m a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR), and I’ve used my experience and knowledge to personally test and review each product on this list.

Note: If you plan to use any of these gravity filters off-grid with untreated water, I recommend properly disinfecting the water before consumption, either beforehand with chemicals like chlorine or iodine, or after filtration with boiling or UV.

Our Testing & Selection Process

The 6 Best Gravity Water Filters

ProductWaterdrop King Tank
Waterdrop King Tank
Epic Pure Water Filter Dispenser
Epic Pure
Alexapure Pro
Alexapure Pro
Clearly Filtered Water Pitcher
Clearly Filtered
ZeroWater 40-Cup dispenser
ZeroWater Dispenser
ProOne Big+
ProOne Big+
CertificationsNSF 372 for lead-free designNot certifiedNot CertifiedNSF/ANSI 42 & 53NSF/ANSI 42 & 53NSF 42 (materials safety only)
Filter Capacity6,000 gallons150 gallons200 gallons/cartridge100 gallons25 gallons1,000 – 1,200 gallons
Cost per Gallon$0.06$0.31$0.59$0.55$0.70$0.41
Warranty1 yearLifetime1 year1 yearVessels 90 days, filters 30 days1 year
Read ReviewWaterdrop King Tank reviewAlexapure Pro reviewClearly Filtered reviewProOne Big+ review

Waterdrop King Tank Performance

The Waterdrop King Tank received the top score of all the filters on this list for contaminant reduction: 9.51.

We tested the system with a water supply that contained lead, aluminum, chloroform, total THMs, chlorine, and manganese, and we were pleased to see that it eliminated 100% of these impurities, along with 93% copper, 40% barium, and 28% sulfate. It comes with separate fluoride filters, which reduced 100% fluoride. Our only disappointment was that, as with many stainless steel countertop systems, the King Tank isn’t performance-certified.

The unit got the top score for filtration rate: 10.00. It filtered water faster than all of the other systems we tested for this guide, with a filtration rate of 4 GPH (gallons per hour)

We awarded the system a 9.40 for design. It was the only gravity water filter we shortlisted that has been certified to NSF 372, for lead-free design, it’s a stainless steel system that comes with a stainless steel/glass spigot as a given (rather than an add-on at an extra cost, as we found with other systems), so the quality was generally high. That said, we did note that it seemed thinner and a bit flimsier compared to other similar systems. 

Waterdrop king tank water filter system on countertop

Our only gripe with the Waterdrop King Tank was its unnecessarily difficult setup process. Assembling the unit was fine, but we had to prime the filters manually, and this was tricky and time-consuming. We awarded the system a lower 6.50 score here. Its maintenance score was also influenced because we had to prime our replacement filters too. Its ongoing cost was super affordable, though, at just $0.06.

We think the Waterdrop King Tank is the best gravity-fed water filter for folks who want to reduce as many contaminants as possible with a system that filters water quickly and is super affordable to maintain in the long run.

Overall Score9.10
Health Related Contaminants9.90
Aesthetic Related Contaminants9.90
Performance CertificationNot certified for any reduction claims
Filtration Rate4 GPH
Component QualityExcellent
Component CertificationCertified
Servicing RequirementsWeak
Warranty Length1 year
ShippingFree shipping to lower 48
Returns30 days

Epic Pure Performance

The Epic Pure Dispenser’s overall contaminant reduction score was 9.00 – one of the highest scores of all the gravity filters we tested. We used it to filter our water containing chlorine, uranium, copper, phosphorous, molybdenum barium, fluoride, nitrate, and sulfate.

It eliminated the first four contaminants, and reduced 57% molybdenum, 41% barium, 27% fluoride, and 20% nitrate, and 92% sulfate.

Again, the Pure dispenser isn’t performance-certified, so it did no better than Waterdrop in this category.

We had a great experience with the setup process for the dispenser; much better than with many of the other systems we tested for this guide. We gave it a 9.50 score because we only had to wash and assemble the pitcher and reservoir, then insert the filter. The filter didn’t need to be primed – we just filtered and discarded the first batch of water. 

Epic Pure Water Filter Dispenser on countertop

This Epic system also had a fast filtration rate of 2.23 GPH, and its simple servicing requirements and low ongoing spend of $0.31/ gal also gave it a great score of 9.50 for maintenance. 

The only area of improvement was design. The Pure dispenser isn’t certified for materials safety, and it got a lower design quality score from us because it’s made from plastic, which felt quite thin and flimsy.

We think the Epic Pure dispenser is the best gravity-fed filtration system for people with smaller budgets who want a capable system that’s easier to install than many stainless steel alternatives. 

Overall Score9.05
Health Related Contaminants9.30
Aesthetic Related Contaminants9.90
Performance CertificationNot certified for any reduction claims
Filtration Rate2.23 GPH
Component QualityGood
Component CertificationNot certified
Servicing RequirementsOutstanding
Warranty LengthLifetime
ShippingFree shipping for the Clean Water Club only

Alexapure Pro Performance

The Alexapure Pro got the second-highest score for contaminant reduction: 9.34. We tested the system using two water sources: one was the same water that we filtered in the Waterdrop King Tank, and the other was untreated river water. 

In our river water test, the Alexapure Pro eliminated all bacteria and greatly reduced aluminum. This is one of the unique benefits of this filter – it’s one of the few gravity-fed filters that can filter unpotable water, too.

In our treated water test, the Alexapure Pro performed the same as the King Tank in reducing 100% lead, chloroform, total THMs, chlorine, and manganese. It also did slightly better at reducing 100% copper and aluminum, as well as 43% barium, but only 16% sulfate. 

However, what let the Alexapure Pro down in this category was that the concentrations of fluoride, magnesium, calcium, and strontium actually increased in our filtered water, and potassium and silver appeared when they weren’t present before.

We think this was due to leaching from the initial 100 gallons of a different water source that we sent through the filters before conducting our test, but our results still showed that the Alexapure Pro didn’t effectively reduce fluoride. This was disappointing because we’d anticipated that the system should reduce >97% fluoride (according to Alexapure’s test results) without a separate filter, which would have given it the edge over the Waterdrop system.

Additionally, the Alexapure Pro doesn’t have any performance certifications, so although its contaminant reduction was overall very good, there’s still room for improvement. 

However, there were a few things that we loved about the Alexapure Pro, and design quality was one of them. It secured the highest 10.00 score here because it’s made from high-quality stainless steel parts, including the spigot. It also did well in the setup and maintenance categories, securing high scores of 9.00 and 8.25 respectively. We didn’t have the hassle of priming the filters, so it was quicker and easier to set up and maintain than the Waterdrop King Tank. 

The Alexapure Pro’s maintenance score could have been higher – its ongoing cost of $0.59/ gallon made it more expensive than its top competitors. 

We think the Alexapure Pro is a great choice for folks who want a gravity-fed filter that effectively reduces a whole host of contaminants (but not necessarily fluoride) and has the easiest setup and maintenance and the highest-quality design. 

Overall Score8.93
Health Related Contaminants9.70
Aesthetic Related Contaminants9.90
Performance CertificationNot certified for any reduction claims
Filtration Rate1 GPH
Component QualityExceptional
Component CertificationNot Certified
Servicing RequirementsGood
Warranty Length1 year
ShippingFree shipping to lower 48
Returns30 days

Clearly Filtered Performance

The Clearly Filtered Pitcher got a score of 8.24 for contaminant reduction. Its score would have been higher, likely securing it in a top-three position, if it wasn’t for one disappointing outcome of our testing: 0.0054 PPM of cobalt was detected in our water after filtration, which we assume leached from the filters (we plan to repeat testing in the future to see if this issue occurs again).

That aside, the Clearly Filtered pitcher did an excellent job of eliminating 100% fluoride, uranium, chlorine, and copper, as well as 86% barium, 67% strontium, 53% molybdenum, and low levels of nitrate and sulfate, from our test water. It also has a performance benefit that no other system on this list has so far: a WQA certification to NSF/ANSI Standard 42, for the reduction of chlorine, and Standard 53, for the reduction of PFOA/PFOS. 

The pitcher’s filtration rate measured at 2.27 GPH, making it slightly faster than Epic’s (2.23 GPH), and it got the highest score of 10.00 in this category.

We’ve tested numerous plastic pitchers that feel thin and flimsy, but the Clearly Filtered pitcher got a high 9.70 score in the design category. It’s made from BPA-free Tritan plastic, which might not be comparable to stainless steel, but we noted that it felt thicker, sturdier, and more durable than most other pitchers we tested. It also has a materials safety certification and a WQA certification for lead-free design.

The CF pitcher actually costs around $15 more than the Epic Pure dispenser upfront, and it has the highest cost of any gravity filter on this list ($0.55/ gallon), but we think its certifications and better design quality make it worth this extra cost.

Installing the top reservoir of the Clearly Filtered pitcher

The Clearly Filtered pitcher is the best gravity-fed water filter for folks who value certifications and want a more portable system that offers a superior filtration performance.

Overall Score8.78
Health Related Contaminants8.30
Aesthetic Related Contaminants9.90
Performance CertificationCertified for 0.82% of reduction claims
Filtration Rate2.27 GPH
Component QualityOutstanding
Component CertificationCertified
Servicing RequirementsOutstanding
Warranty Length2 years
ShippingFree shipping
Returns30 days

ZeroWater Performance

The ZeroWater Glass Dispenser secured an 8.34 score – the same as Clearly Filtered – for contaminant reduction. Its overall performance in our testing was exceptional, with our results showing that it reduced 100% fluoride, chlorine, uranium, barium, strontium, molybdenum, nitrate, and sulfate, as well as 97% copper. 

However, as with Clearly Filtered, there was one outcome of our ZeroWater test that pulled down its contaminant reduction score: 3.4 PPB of chloroform was detected in our filtered water. That meant this harmful disinfection byproduct hadn’t been effectively reduced by the filter and was present at levels exceeding the lab’s Health Guideline Level of 0.2 PPB.

On a better note, the dispenser has NSF Standard 42 and Standard 53 certifications for reducing chlorine taste and odors, mercury, lead, PFOA, PFOS, and hexavalent chromium, giving it an advantage over many other gravity-fed filters, especially the stainless steel units.

Brian next to the ZeroWater Glass Dispenser

We were also impressed with ZeroWater’s filtration speed of 2.62 GPH, making it slightly faster than most other gravity-fed systems we shortlisted, although not as fast as Alexapure. 

We also awarded the dispenser a high setup score (9.50), and it was the easiest to assemble of all the systems we tested, requiring no filter flushing, priming, or soaking.

There’s a TDS meter included with the dispenser, which we found helpful in checking the filter’s performance and lifespan. We were instructed in the user manual to replace the filter when the TDS meter reading was 006, so we didn’t have to guess with this aspect of maintenance as we did with other systems.

Zerowater tds meter

But we were disappointed with the filter’s 40-gallon capacity, which meant it needed replacing far more frequently than any other gravity filter we tested. This brought its ongoing cost up to $0.70/ gallon: over 10 times Alexapure’s cost per gallon.

We think the ZeroWater Glass Dispenser is the best performance-certified gravity-fed water filter for folks who want to limit their water’s contact with plastic and prefer the look of a glass dispenser over stainless steel.

Overall Score8.74
Health Related Contaminants8.30
Aesthetic Related Contaminants9.90
Performance CertificationCertified for 25% of reduction claims
Filtration Rate2.62 GPH
Component QualityExceptional
Component CertificationCertified
Servicing RequirementsOutstanding
Warranty LengthVessels 90 days, filters 30 days
ShippingFree on orders over $60 to continental US
ReturnsNo returns

ProOne Big+ Performance

The ProOne Big+ secured a score of 8.44 for contaminant reduction – that’s slightly higher than Clearly Filtered and ZeroWater, but not as high as Epic or the other stainless steel systems. 

It eliminated 100% lead, copper, fluoride, aluminum, and manganese in our testing, but its score was affected by its inability to effectively address disinfection byproducts: it reduced just 47% of total THMs and 56% chloroform. 

In our untreated river water test, we were pleased with our Big+ results, which showed that the filter had eliminated all three bacteria types detected in our unfiltered water.

But there was no difference in the performance certification category: like the other stainless steel gravity filters, the Big+ isn’t certified. 

This ProOne unit combined the best design features of the other two stainless steel systems: the same high-quality, durable steel design as the Alexapure Pro, and a design certification like the Waterdrop King Tank (in this case, a materials safety certification for the filter elements themselves), awarding it the highest 10.00 score in this category.  

We had an easier time setting up the system than we did with Waterdrop, although not quite as easy as Alexapure. The filters didn’t need priming, but we still had to scrub them under cold water with a scouring pad. The lack of filter priming also meant the Big+ secured a good maintenance score of 8.75, although it has a higher ongoing servicing cost of $0.41/ gallon.

The ProOne Big+ is the gravity-fed filter we recommend to folks who want the most affordable stainless steel system with a high-quality design, easy setup and maintenance, and suitability for emergency preparedness situations. 

Overall Score8.56
Health Related Contaminants8.65
Aesthetic Related Contaminants9.90
Performance CertificationNot certified for any reduction claims
Filtration Rate0.77 GPH
Component QualityExceptional
Component CertificationExceptional
Servicing RequirementsGood
Warranty Length5 years
ShippingFree shipping on orders over $69.95 to the lower 48 states
Returns30 days
  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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