Aquasana AQ-4000 Review

Aquasana AQ-4000 Review (2022)

The importance of drinking water and the difference it makes to your health is a no-brainer. However, if you’re choosing water over a cuppa Joe, you’ll want to ensure your expectations are met. While tap water ushers in immense convenience and should be the obvious choice, it’s not always as pure as you might assume.

Given that you typically don’t need to sterilize your water before consumption, it’s easy to assume that there are no qualms with what stems from the faucet. While the chances of being instantly struck down with a case of diarrhea are slim, swigging the water that comes out of your faucet can still cause adverse repercussions.

Here’s where a countertop water filter comes into play. However, finding the best unit can be an uphill battle with the wealth of options that have littered the market. In this Aquasana AQ-4000 review, we’ll explore why it’s one of the best options to consider.

Aquasana AQ-4000W Countertop Drinking Water Filter System, White
  • Removes over 97% of chlorine and reduces 76 other contaminants - NSF certified to remove lead, pharmaceuticals and more

Aquasana AQ-4000 Review: Features

Like other high-end products, the Aquasana AQ-4000 contains amazing features that make it a worthwhile investment for household use.

1. Two-Stage Claryum Filtration

The main task of a water filter is filtration. The unit uses state-of-the-art Claryum technology that entails two filtration stages to guarantee clean, pure water. The stages are further broken down into four segments.

  • The activated carbon filter diminishes organic chemicals such as herbicides and pesticides from the water.
  • Catalytic carbon filtration aids in the elimination of up to 97% of chlorine and chloramine. These are responsible for unpleasant odor and taste in the drinking water.
  • The ion exchange technology guarantees the elimination of lead, mercury, and other heavy metals.
  • Lastly, the sub-micron filters capture and get rid of cysts lurking in the water.

2. NSF Certification

Seventeen different products from Aquasana have NSF certification, including the AQ-4000 countertop filter. The brand maintains consistent compliance with the NSF guidelines. In turn, it’s been able to maintain this certification for years. All its filters undergo rigorous testing and have a data sheet that shows test results. According to the sheet, the AQ-4000 has a 99% success rate in eliminating most water contaminants.

3. Design

The AQ-4000 features a sturdy build that’s complemented by a user-friendly design. Connecting it to the faucet and replacing the filters when need be is a walk in the park. Furthermore, the unit features an activated carbon filter geared towards removing up to 77 contaminants.

4. Filter Unit

The filter is housed in a rectangular white unit that’s designed to sit on kitchen countertops. The unit’s design varies from the generic cylindrical unit and occupies a larger surface area for width. Nonetheless, it’s compact and ideal for those with limited counter space between the wall and kitchen sink.

5. Flexible Faucet Adapter, Hose, and Diverter Valve

You’ll require attaching the AQ-4000 to the faucet of your kitchen sink via the diverter valve and hose. If you lack a standard faucet, you might require using the included adapter to directly connect your faucet to the diverter valve.

6. Warranty

It’s the cherry on top for customers. You can have peace of mind knowing that the AQ-4000 is backed by a one-year warranty and a 90-day money-back guarantee, enhancing their confidence in the unit.

Aquasana AQ-4000 Review: Performance

When it comes to filtering performance, the AQ-4000 is undoubtedly one of the forerunners in the world of countertop water purification and filtration. The unit’s filter has been proven to eliminate 77 contaminants such as PFOs, lead, pesticides, mercury, pharmaceuticals, and herbicides, and it’s more efficient than other filters. Additionally, it can last for 11 times the capacity of the brand’s gravity-fed pitcher.

Once you attach the unit to your faucet, you’ll gain from your home’s water pressure forcing it to flow through the filter at an impressive rate of 30 gallons per hour. That implies you can drink filtered water immediately with no waiting time. If you prefer having immediate access to clean, pure drinking water, the Aquasana AQ-4000 is a no-brainer.

Aquasana AQ-4000 Review Near Faucet

Aquasana AQ-4000 Review: Flow Rate

Once the filter is connected to your faucet, you won’t need to hang around to fill up a pan of water. Although the flow rate might slow down after a while, there’s no denying that it’s impressive at 30 gallons per hour. That will give you an adequate supply for cooking and drinking without any frustrating delays.

It’s also worth noting that contrary to other filtration systems that depend on reverse osmosis, the Aquasana AQ-4000 guarantees no water wastage. Every ounce of water that comes out of your faucet will be purified, filtered, and ready for consumption. Reverse osmosis systems can waste up to 3 gallons of water per purified gallon which isn’t ideal.

Aquasana AQ-4000 Review: Installation

As a countertop filter, the installation doesn’t call for considerable effort and time. Nonetheless, here’s a step-by-step guide for beginners.

  1. For starters, detach the aerator from the faucet by twisting it off
  2. Connect the diverter valve after confirming that the rubber washer is firmly in position
  3. Use the included hex wrench to screw the bass adapter
  4. Keep your eyes peeled for two holes at the base of the system into which you’ll jerk hoses
  5. Insert the white and blue tips into the appropriate caps
  6. Open the faucet and ensure there’s no leak
  7. After pulling the diverter pin, allow the AQ-4000 to flush for 10 to 20 minutes.

The Components

The Aquasana AQ-4000 comprises the following parts.

  • Threaded cartridge caps
  • Plastic hex wrench
  • Two filter cartridges
  • A snap-on cover
  • Two O-rings
  • Rubber washers
  • The hose assembly and faucet diverter valve
  • Two different-sized brass faucet adapters (15/16″ and 13/16″)
Aquasana AQ-4000W Countertop Drinking Water Filter System, White
  • Removes over 97% of chlorine and reduces 76 other contaminants - NSF certified to remove lead, pharmaceuticals and more

Aquasana AQ-4000 Review: Care and Maintenance

Maintenance is crucial to making the most of your water filter and ensuring it serves you well for years down the road. Given that the capacity of the filter is 450 gallons, it requires replacement upon reaching its limit. Although it depends on the quantity of water filtered per day, we advise replacing the filter every six months.

The best part is that you don’t need to rope in a professional plumber for the replacement. It’s a straightforward and quick process that entails turning the filter cap, removing the cartridge, and connecting the new one. When it comes to day-to-day maintenance, it’s worth noting that the unit is only compatible with cold water. Filtering hot water results in premature wear of the components.

Aquasana AQ-4000 Review: Pros and Cons

Investing in a water filter is essential, particularly for people serious about their health and who want to delight in clean, great-tasting water. To help you determine whether the AQ-4000 is a great fit for your home, we’ve rounded up the pros and cons.


  • Excellent Flow Rate

One of the main perks of this unit is the amazing flow rate. With 0.4 gallons per minute, it can produce 30 gallons of purified and filtered water hourly.

  • Portable

This unit’s lightweight nature and compact size make it more portable than other water filters on the market. You can easily transport it with you on your travels and when shifting homes, making it a long-term investment.

  • Easy Installation

With no permanent fixture necessary and a step-by-step instruction manual, the installation takes five to ten minutes.

  • Eco-friendly

With a relatively sufficient filter capacity, the AQ-4000 doesn’t require filter replacements, ultimately reducing plastic waste. Therefore, it’s an eco-friendly option.


  • Pricey Maintenance

The maintenance of this unit surpasses other filters in the market. However, since the cartridges are costly, the annual replacement cost can dent your wallet.

  • Leakage

Some users notice leakage from the bottom of the unit. Nevertheless, manufacturers make up for the loss with free replacement parts.

Aquasana Active Clean Machine vs. Aquasana AQ-4000: What’s The Difference?

It’s no secret that the brand has introduced a boatload of water filters to better people’s lifestyles. However, the Aquasana Active Clean Machine and AQ-4000 each have their strengths and weaknesses. Although they both serve the main purpose of purifying and filtering water, a few underlying differences are discussed below.


One of the main issues with the Aquasana Active Clean Machine is its noisy operation. Contrarily, the AQ-4000 operates silently. So, you’ll hardly notice its presence.

Flow Rate

Another difference between the two units is the flow rate. While the Active Clean Machine has a speed of 0.5 GPM, the flow rate of the AQ-4000 is about 0.4 GPM.


The Active Clean Machine calls for filter replacement every 2 to 3 months, even with minimal usage. On the other hand, the filter of the AQ-4000 usually lasts for six months, making it more cost-effective.

The Bottom Line

From these in-depth Aquasana EQ-4000 review, there’s no denying that it’s an ideal water filter for large and small households. Without the hassle of under-sink installation, it’s portable and easy to fit. While the cost of the drinking water filter is greater than other options on the market, as with everything else in life, you get what you pay for.


Let’s explore the answers to some of the most commonly asked questions about the Aquasana water filter.

How do you know when it’s time to replace the unit’s filters?

The filter capacity of the AQ-4000 is 450 gallons which translate to 6 months. Therefore, you’ll need to change your filters when you 6 months elapse or you’ve filtered 450 gallons of water.

What BPA? Why should you be concerned about it?

BPA is an acronym for Bisphenol-A, a contaminant commonly found in plastics. It can be detrimental to your health if consumed at high levels. The AQ-4000 and other Aquasana systems lack BPA, allowing you to enjoy pure, clean water.

How do you know if the AQ-4000 is compatible with your faucet?

The filter isn’t compatible with two-in-one faucets that have a detachable sprayer at the faucet opening. Nonetheless, the unit is a snug fit in most standard faucets and has two adapters. If your faucet is a non-standard size compared to the adapters or hose connection that come with the AQ-4000, you can take the aerator to your local hardware store and have it measured. Once you know its size, you can buy the perfect-sized adapter.

Can you bypass filtration when you’re washing dishes?

Yes! There’s a bypass lever that allows you to turn off the filter and switch to your unfiltered tap water.

What is Claryum technology, and what purpose does it serve?

It’s a selective filtration process that utilizes adsorption, sub-micron filtration, and micron filtration. Collectively, Claryum technology diminishes up to 99% of contaminants lurking in the water, ranging from asbestos, Led reduction pH 6.5, benzene, turbidity, and giardia to cyst live cryptosporidium. Moreover, it does so while maintaining potassium, magnesium, calcium, and other healthy minerals.

Does the unit’s filter soften water?

The AQ-4000 softens water in numerous ways due to its various filtration techniques. Its utilization of water ionization diminishes and eliminates harsh minerals and metals. However, the unit isn’t a water softener. Partially softened water is just a bonus when it comes to filtration performance.

Is the unit renter-friendly?

The AQ-4000 is compatible with renters, given that it doesn’t require drilling holes or connecting additional water lines to your home. Instead, it sits on your kitchen counter for everyday use.

Does the unit purify water?

Most people don’t realize that purified water is different from filtered water. Purified water undergoes procedures that eliminate everything, including beneficial minerals. The AQ-4000 gets rid of harmful contaminants while retaining the essential minerals that foster good health.

How do you replace and dispose of the filters?

The replacement filters for the AQ-4000 are a breeze to set up and find online. Moreover, they are biodegradable. You have free rein to send your old filters to Aquasana, and they’ll dispose of them on your behalf. Alternatively, you can throw them in the dumpster with little environmental repercussions due to their composition.

Aquasana AQ-4000W Countertop Drinking Water Filter System, White
  • Removes over 97% of chlorine and reduces 76 other contaminants - NSF certified to remove lead, pharmaceuticals and more

Amanda Perkins

Amanda began her career as a technical writer for a healthcare group in 2008. Years after getting married and starting a family, she joined her husband Joshua on the Water Filter Authority journey to educate other families and households about safe, affordable, and effective water filtration systems.