Review: Aquasana Claryum AQ-4000 Countertop Water Filter

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Please note: Apparently, the Aquasana Claryum AQ-4000 Countertop Water Filter is not available for sale anymore. However, replacement filter cartridges are still sold by Aquasana.

The Aquasana Claryum AQ-4000 is a countertop water filter system that converts plain tap water into clean, great-tasting drinking water on demand.

Thereby, the unit does not require permanent installation to your plumbing system or kitchen sink whatsoever. Quite the contrary: The AQ-4000 attaches to standard-sized faucets in a matter of minutes, no tools required… A solid investment?

Aquasana Claryum AQ-4000 Countertop Water Filter

Aquasana Claryum AQ-4000 Countertop Water Filter

Price: $
Filter Process: Activated Carbon, Catalytic Carbon, Ion Exchange Resin, Submicron Filtration
Filter Life: 450 Gallons
Flow Rate: 0.5 gpm
Annual Cost: ~$120

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Aquasana Claryum AQ-4000 Countertop Water Filter – All Specs

  • Model: AQ-4000
  • Annual Maintenance Cost: ~$120
  • Filter Media/Process: Activated Carbon, Catalytic Carbon, Ion Exchange Resin, Submicron Filtration
  • Filter Stages: 3
  • Flow Rate: 0.5 gpm
  • Filtering Capacity: 450 gal or 6 Months
  • Water Temperature: 40-90 °F
  • Water Pressure: 20-80 psi
  • NSF Certifications: Standards 43, 53, 401
  • Warranty: 1-Year (Limited)

Aquasana Claryum AQ-4000 – Key Features

Once set up, the Aquasana Claryum AQ-4000 Countertop Water Filter uses 2 filter cartridges combining 3 filter stages. Activated carbon, catalytic carbon, and ion exchange filter media as well as submicron filtration help you get rid of:

  • Chlorine and chloramines
  • Heavy metals such as lead
  • Asbestos
  • Chlorine-resistant cysts like giardia and cryptosporidium
  • Organic chemicals including forever chemicals, pesticides, pharmaceuticals, and VOCs

The total number of contaminants that the system has been tested and NSF-certified to remove is 77 with some reduction rates over 99%. Now this is really good!

Which NSF standards? 42, 53 (includes P473), and 401 – awarded by the WQA. In other words, you can rely on the claims made in the performance data sheet, meaning the Aquasana Claryum AQ-4000 is effective at removing most water contamination.

By the way, the flow rate you can expect is around .5 gallons per minute, so a bit slow.

Filter cartridges are rated at 450 gallons or 6 months. We estimate $120 in annual filter replacement cost which is acceptable.

And finally, there are no tools required for installation. You just have to be careful because the Aquasana AQ-4000 is not compatible with all faucets. For example, it does not fit pullout sprayers. Most standard faucets are fine. Also, the package includes two faucet adapters.

Aquasana AQ-4000 Countertop Water Filter Image 1

Aquasana Countertop Water Filter Pros

Usually when a water filter removes that many impurities it also eliminates some of the good stuff – think essential minerals. Not so with the AQ-4000. Most calcium, potassium, and magnesium will be preserved and contribute to your total daily mineral intake.

Another advantage is that you can easily switch between filtered and unfiltered water without having to uninstall the unit. Simply pull or push the pin on the diverted valve as needed.

This plus the compact size is also the reason why this countertop water filter is highly portable. And it doesn’t take up much space on your counter.

Did we mention that everything is covered by a 1-year limited warranty + a 90-day “PURE SATISFACTION” guarantee (full refund of the purchase price, no questions asked)?

What Contaminants Are Being Removed?

With the Aquasana Claryum AQ-4000 Countertop Water Filter, you’ll get rid of:

  • Chlorine – 97.4%
  • Chloramine – 97.4%
  • Particulates class I – 99.9%
  • Asbestos – 99%
  • Cyst – 99.99%
  • Lead – 99.3%
  • Mercury – 95.8-96.5%
  • MTBE – 86.6%
  • PFOA & PFOS – 95.8%
  • Turbidity – 99%
  • Pesticides, Pharmaceuticals, industrial chemicals – up to 98.9%
  • About 50 VOCs – up to 99%

Aquasana Claryum AQ-4000 Countertop Water Filter

The Aquasana Claryum AQ-4000 – learn more on


Like we said, the Aquasana AQ-4000 is really simple to set up without the need for tools – no permanent fixtures or installation required! But remember: The countertop water filter is only compatible with standard-sized faucets. So for example, pullout sprayer-type faucets won’t work.

Here is what you need to do:

Please consider these instructions as a general guideline. Always make sure to check and follow your user manual before getting started.
  1. Remove the aerator from your kitchen faucet.
  2. Make sure the rubber washer on the diverter valve sits in place.
  3. Attach the diverter valve. You may need to use one of the brass adapters (included). If so, tighten the adapter with the plastic hex wrench tool (included).
  4. Push the two hoses into the holes on the bottom of the unit (turning it upside down). The blue tip goes into the blue cap, the white tip into the white cap.
  5. Open your faucet and check for leaks.
  6. Pull out the diverter pin.
  7. Flush for 10 minutes.


The Package (Parts)

  • Filter Unit with Cover
  • 2x Brass Faucet Adapter
  • 2x Rubber Washer
  • Filter Cartridges
  • Threaded Cartridge Caps and O-Rings
  • Faucet Diverter Valve
  • Hose Assembly


In theory, filter replacements couldn’t be more straightforward. All you really have to do is put the unit on its side, twist off the filter caps, take out the old cartridges and insert new ones – shouldn’t take more than 2 minutes, right?

Yeah, not quite. The caps get stuck easily making the whole process a nightmare. Some users would even order a whole new unit because they couldn’t manage to open their old one. A possible solution to this is to remove the blue filter first. Then use the fins on its end to twist the fins of the white filter. And make sure to not install both in the same direction. The white goes in nipple-first, the blue one the other way round.

At least you only have to do this about every 6 months or 450 gallons…

Again, we estimate $120 in annual filter replacement cost which we find acceptable. Also, you can get 15% off with a filter subscription.


Here is a link to the official manual:

NSF and Other Certifications

The WQA (Water Quality Association) has tested and certified this system for NSF/ANSI standards 42, 53 (including P473), and 401. What does this mean for you?

  • NSF 42 covers chlorine, chloramine, particulate class 1, taste, and odor reduction.
  • NSF 53 means this filter will also reduce asbestos, cyst, lead, mercury, MTBE, PFOS, PFOA, turbidity, and VOC (as chloroform).
  • NSF 401 covers Bisphenol A, Estrone, Microplastics, Naproxen, Nonyl Phenol, Phenytoin.

Earlier Product Versions

To our knowledge, this system does not have earlier versions.

Aquasana AQ-4000 Cons

Filter replacements are by far the biggest issue. After 6 months of use the filter caps are likely stuck having caused multiple incidences of bloody knuckles. And for some users, the filters didn’t even last six months.

The next problem is leaking. Either water will pour out the bottom of the unit or out of one of the hoses or the diverter. If the pin is leaking, it’ll spray water all over the place. The good news is that the manufacturer is usually willing to send replacement parts free of charge.

We also found out that some customers experienced a very low flow rate, and having water trickle slowly out of your unit can be annoying.

And lastly, the diverter. It might get stuck due to corrosion or keeps popping out so that you can’t switch between pure and plain tap water anymore. A simple tip we read in one of the customer ratings is to grease the pin with vegetable oil.

Aquasana Claryum AQ-4000 Review: Our Verdict + Best for

Bottom line: The Aquasana AQ-4000 provides pure water with great taste – backed by NSF certification. Although there have been issues, for the vast majority of people the countertop system has done a great job as long as filters are changed on schedule.

The price is affordable. And considering the 90-day money-back guarantee, what can really go wrong? Our verdict: 4.0 stars!

The Aquasana AQ-4000 is best for people looking for an affordable yet effective countertop water filter that’s NSF-certified for removing a wide range of contaminants from drinking water.

Our Rating in Detail:

  • Filtration Performance: 4.5/5.0
  • Filter Capacity (Life): 4.0/5.0
  • Purchase Price: 4.5/5.0
  • Annual Cost: 4.0/5.0
  • Overall: 4.0/5.0

Comparison to Other Countertop Water Filters

Time to compare! This time, we’re taking the Aquasana AQ-4000 against the AquaTru and the ProOne PMC-3000.

AquaTru Reverse Osmosis Water Filtration System


Price: $$$
Filtration Process: Sediment/Carbon, RO, Carbon Block
Filter Life: 600-1,200 gal
Water: 1 Gallon in 10-15 Minutes
Annually: ~$100-120

Overall Rating: 4.5/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Get 15% Off! Use Code: BOSAQUATRU

ProOne ProMax PMC-3000 Countertop Water Filter

ProOne ProMax PMC-3000

Price: $$
Filtration Process: Ceramic Outer Shell, Carbon Block Core
Filter Life: 900-2,600 gal
Water Flow Rate: 0.2-1.0 gpm
Annually: ~$85

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

Aquasana Claryum AQ-4000 Countertop Water Filter

Aquasana Claryum AQ-4000

Price: $
Filtration Process: Activated Carbon, Catalytic Carbon, Ion Exchange Resin, Submicron Filtration
Filter Life: 450 gal
Water Flow Rate: 0.5 gpm
Annually: ~$120

Overall Rating: 4.0/5.0 ⓘRating based on filtration performance, filter life, price and yearly cost, NSF testing/certification, customer support, product warranty, our testing/experience, user feedback, and other factors.

The AquaTru is an installation-free countertop RO system. That means (1) you can set it up for work in just a few minutes, and (2) it saves space. As an RO system, the AquaTru is more thorough than the regular countertop water filter. Normally, that would mean it wastes a lot of water, too, but no. The AquaTru uses an internal pressure pump that raises its recovery rate to 80% — so only 20% of water goes to waste. That’s really impressive, especially since most RO systems waste three to five gallons per gallon of purified water.

Did we mention that the AquaTru is our #1 RO water filter? Apart from the reasons mentioned above, here’s another reason why it’s our favorite:

The AquaTru’s four-stage filtration has been rigorously tested and certified against five NSF standards (42, 53, 58, 401, and P473), covering almost 80 water impurities. What does that mean? You’ll definitely get clean and healthy drinking water, devoid of these contaminants at the specified rates:

  • Chlorine – 96.6%
  • VOCs – 95% to over 99%
  • Chromium 6 – 97.2%
  • TDS – 87.1%
  • Cyst – 99.99%
  • Fluoride – 93.5%
  • Lead – 99.1%
  • Radium 226/228 – 96.4%
  • BPA – 99%
  • Several trace pharmaceuticals and pesticides – 86.7%-96.6%
  • PFOA & PFOS – 97.5%

The AQ-4000 has been tested similarly, so it’s on par with AquaTru here.

Other perks you get with the AquaTru include speedy filtration, easy navigation, and safe design materials (it uses only plastic that does not contain BPA and BPS).

On the flip side, some AquaTru units have stopped working after just a few months. Some also leaked. We learned about these issues from customer reviews, but we didn’t experience them when we used the system. One more thing to note, though, is that the AquaTru is more expensive than the Aquasana AQ-4000 upfront. However, it costs about the same amount to maintain.

The other system, ProOne PMC-3000, consists of layers of foam-structured filter media. Each layer has granulated activated carbon and other specialized media targeting a particular set of contaminants. The system has been thoroughly tested against NSF standards 42 and 53 for over 200 contaminants! It has these reduction rates among others:

  • VOCs – 99.9%
  • Lead – 99.4%
  • Arsenic 3+5 – 98.0%
  • Nickel – 99.0%
  • Chromium 3+6 – 98.3%
  • Several pesticides and herbicides – 95.2-99.9%
  • Semivolatile contaminants – 99.8%
  • Chlorine – 95.5%
  • Chloramine – 96.7%
  • Nitrates – 61.3%
  • Nitrites – 72.4%
  • Sodium fluoride – 90%
  • TDS – 86.7%
  • PFOA/PFOS – 99%
  • Trace Pharmaceuticals and other chemicals – 99.5%

Really thorough and impressive testing, but, unfortunately, no NSF certifications. That means we have to rely on the test data being accurate. The Aquasana, on the other hand, has official NSF certifications but fewer tested contaminants.

And like the Aquasana, the ProOne has faucet adapters and is easy to install. You also get a diverter valve that allows you to switch between filtered and unfiltered water easily. The filters are very easy to change, and they only need replacement once a year or after filtering 900 to 2,600 gallons. You’ll spend about $85 yearly, which is quite affordable. Lastly, a 2-year limited warranty covers the filter.

On the downside, the ProOne system is quite expensive. The flow rate can also be really low, ranging between 1 gpm and 0.2 gpm. While 1 gpm is manageable, 0.2 gpm is just too low.

What can we conclude? If you’re looking for a thoroughly tested and certified RO water filter (with great perks like fast filtration, little wastewater, and zero installation), the AquaTru is the perfect choice. Aquasana and ProOne are both effective options for regular countertop filters.

This completes our review of the Aquasana Claryum AQ-4000 Countertop Water Filter. If you have any questions please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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