Aquasana AQ – 4000 Counter Top Water Filter Review

If you have ever searched for quality water filter units before, it is a safe bet to assume you have come across the name Aquasana. Founded in 1998 Aquasana is one of the most trusted brands in the home water filtration market. Don’t take our word for it, they have over 15,000 certified positive reviews on their website. 

From their wide variety of countertop water filters available we have decided to start by carrying out a comprehensive “Aquasana AQ 4000 Review ” for you. We chose the AQ 4000 to review is because it is their top selling unit. With so many customers, it’s no surprise there are contradictory reviews.

Aquasana AQ 4000 Counter Top Water

With so many varied opinions, the reviews can actually confuse you more. so, we will go over the pro’s and con’s and you can make your own mind up if this is the best countertop water filter for your needs. 

After doing extensive research and getting honest Aquasana AQ 4000 reviews from the actual users,  we are here to report everything we found to you. So that at the end of the day, you can make an informed decision about your purchase.

Aquasana AQ 4000 Review

Aquasana is the leading brand in the countertop water filter industry. They are renowned for manufacturing filters that don’t just perform really well, they look great in your kitchen too. Aquasana has been in the industry for many years, constantly developing and researching new and improved technologies in water filtration. Using their experience and industry knowledge to provide great products and benefits to their customers.


Aquasana AQ-4000w Counter Top Water Filter

No plumber required – replacements are a simple twist

About this item

  • 20+ Organic Green Veggie Whole Foods – Wheat Grass, Spirulina, Chlorella & More – Antioxidant, Digestive Enzyme & Probiotic Blends | Vegan Juice Supplement

Their philosophy is entirely different from the competitors and even the technology that they are using is different. They have manufactured their Aquasana AQ 4000 countertop filter by considering the real problems users reported having. But it does still have some shortcomings. Be patient! In this review, you will get every minute detail about this water filter.

Let’s start exploring more about this unit in more detail.


Filtering the water is the core task that water filters have to do, right? Of course it is, and if they failed to do that one thing well you would not buy it, right? Obviously, you would not choose a filter that was not good at filtering your water, right? You wouldn’t, no matter how easy to install and how stylish they were. Aquasana understands that beauty and ease of install are important, but first and foremost it must be a great water filter. 

Aquasana uses proprietary Claryum filter technology. It filters out pollutants from the water while retaining beneficial minerals in the water, something that no other filtration technology currently does. Other filter systems require remineralization of water after filtration.

Claryum technology uses two filtration stages in the whole process.  Furthermore, these two stages are divided into 4 different portions, to ensure that you will get nothing but pure, purified water.

Activated Carbon

Activated carbon is very effective at removing organic chemicals and pesticides that may be present in your water. This is especially important if your water comes from a reservoir in a rural area where pesticides and weed sprays may run off into the water supply.

Catalytic Carbon

It only works to remove two chemicals including chloramine and chlorine. It has been suggested that catalytic carbon effectively removes up to 98% of chloramine and chlorine. Water companies add chlorine to the water to prevent nasty bacterial contaminations.

Although it is reported chlorine is “safe” in small levels you do not know how high the concentrations are. Chlorine also makes your water smell like an indoor swimming pool. 


This is where all the Lead and mercury will get eliminated from the water. Lead and other heavy metals are common contaminants in the water supply, especially if your water travels through old pipes. 

Sub-Micron Mechanical Filtration

Lastly, chlorine-resistant cysts and asbestos get caught at this segment.

Long story short, this filter will remove almost all water contaminants. Including chlorine, chloramine, heavy metals, organic chemicals, pesticides, and other possible pollutants are eliminated by the Aquasana AQ 4000.

But because the Aquasana AQ 4000 does not remove all the beneficial minerals, like potassium, magnesium, and calcium remains you get the health benefits.  Without leaving bland tasteless purified water. You can be sure the water coming out of this filter is the cleanest and healthiest water.

Why You Should Trust Its Filtration Capabilities?

Every filter brand and model claims to do the same thing, but they are not all filtering the water effectively. And many filters on the market are not regulated. So you can’t just believe their claims without having strong evidence in your hand.

You might be thinking to yourself, that Aquasana’s claim is also just a marketing gimmick like so many others. However, Aquasana ensures all its products meet the highest level of scrutiny.

The Filters of Aquasana AQ 4000 are NSF internationally Certified. Aquasana holds NSF/ANSI standards 42, 53, and 401 certificates. You can be confident there is no doubt in the quality of water that is filtered with this great compact unit.

For more satisfaction, you can check out their official testing and certification results Here.

Flow Rate

Counter Top water filters provide you the filtered water on demand. You can easily switch from filtered to unfiltered water when you need it. For instance, you would not fill the sink and wash dirty plates with filtered water. Unlike most reverse osmosis systems, countertop filters don’t have storage tanks. That’s why filling up your glass with purified water from a counter top filter is slower.

The flow rate of Aquasana AQ 4000 is around 0.5 Gallons per minute, producing a maximum of 30 gallons of purified water, in one hour. Which is more than enough filtered water for home consumption. No need to stand and wait as filtered water slowly fills your glass, and no pre-filling containers to store for a quick drink, simply flip the tap and fill your glass.


One thing I really love about a countertop water filter is how simple they are to set up and use. They don’t require any sort of complex installation, you simply place it on the countertop and connect it directly to your faucet.

They don’t require any permanent installation so you can set it up within a couple of minutes.

This is great if you have limited bench space, easily disconnect the unit and take it off your countertop until you need it again. 

For installation instruction, you can consult the Aquasana AQ 4000 instruction manual Or watch the quick video below.


The biggest drawbacks of countertop water filters are their smaller filter size. This means you will need to replace filters far more often than a multistage reverse osmosis filter. However, you will still get great value for money, and the filters are so simple to change that it only takes a minute.

The official guideline is a 6-month filter life, but this is only an estimate based on the average household consumption. Your replacement period will vary, it solely depends on the volume of water you filter in a day. But because the filters are so simple to replace, we suggest changing them sooner than you think you should so you ensure the filter is working at its best. 


As good as the AQ 4000 is, it is not without drawbacks, every filter has its limitations and negative features, and this unit is no exception. 

The filtration capability and the ease of installation, of the AQ 4000 are great. But… these are some limitations that you should consider before making any final decision.

  • The maintenance cost of the filter is higher than many other filters because the filter cartridges are quite expensive. The cost of replacement cartridges can be more than half the cost of an entirely new unit. This is because the filters are where all the technology is, and what makes the AQ 4000 a great water filter. Although, given that filters are only changed every 6-12 months they won’t cost an arm and a leg. And will cost far less than buying ridiculously overpriced bottled water.
  • On rare occasions, there have been units that have leakage from the bottom. Thankfully, Aquasana is known for its excellent customer service. They will respond quickly and be more than happy to send you free replacement parts. This fault is very uncommon but just keep an eye on it.
  • AQ 4000 filters are not recommended for filtering water that comes from a well, they are only suitable for filtering municipal water.

Who Should Buy the Aquasana AQ 4000?

This Aquasana AQ 4000 is an ideal filter for small households not needing a large inline filter system. They are ideal for tenants as the install process is 100% damage-free. They can be removed and taken with you when you move homes. 

Summing it up you should consider buying the AQ 4000 if:

  • You are on a budget and want a great quality water filter. 
  • You are a tenant and are unable to install a permanent inline water filtration system.
  • Your water has a chlorine taste from the Municipal water supply.
  • You want to save money by not buying bottled water. 

Final Thoughts

Overall, after reviewing the Aquasana AQ 4000 we think that it is a very affordable water filter with great water filtration capability. We are impressed by the quality and taste of water filtered using this unit. It impressed us and all of the customers with its sleek design and exceptional filtration capabilities. This is a quality home water filter without a high price tag.

The main unfounded complaint people have is with the maintenance cost, being too high. But at the current price, we think overall it is a very affordable, high-quality unit.

If your main goal is to avoid buying expensive bottled water, then this is the ideal solution that will save you a whole lot of money. We believe this to be the best-performing countertop water filter on the market.

Similar Posts