Best Under Sink Water Filter – Reviews, Awards, And Discounts 2021


Under-sink water filters are the perfect choice for those who don’t want to invest in a whole-house system but aren’t satisfied with a faucet filter‘s capacities either.

Among the reasons why people go for under-sink filters is that they’re pretty space-saving and easy to manage. Since they’re installed under your faucets, these water filtration systems are hidden away neatly inside cupboards, where you only have to adjust their settings every once in a while.

Best Under Sink Water Filter

Because the market is overwhelming and there are many products to choose from, we’ve put up a best-of list that you can use as a guide. Water Whizz has covered some of the most important fields of water filtering (see: best pitchers, RO systems, distillers), so you can wholeheartedly trust our expertise. To ensure that there’s a fair choice for everyone, we have included all types, models, and under-sink filter price ranges*. If you find yourself confused at any step of the way, make sure to check out our fully comprehensive water filters review.

*The prices of all under-sink water filters were correct at the time of writing.


Best Under-Sink Water Filters of 2021

1. Waterdrop WDTSCW Under-Sink RO Filter ($124.99)

* Waterdrop’s Spring Sale offers three discounts: SPR10, SPR15, and SPR50 *

Waterdrop manufactures the best under-sink water filter of 2021, and it goes by the WDTSCW tag. Before we get into the product, we must note that the brand is one of the industry’s most respected companies. What started with affordable refrigerator filters shaped into a much larger production pool, including whole-house systems, faucet filters, countertop filters, and more. The premium-grade filter operates with reverse osmosis functions, which means that your water will be filtered twice over for optimal results. The under-sink RO filter is tested against the NSF standards for optimal water treatment, so you know they’re game. 

Thanks to its dual-carbon filtration mechanism, this system can reduce dozens of contaminants from both city and well water supplies, with an effectivity rate of up to 99%. Among the most notorious, Waterdrop secludes chlorine, mercury, lead, VOCs, herbicides, pesticides, fluoride, arsenic, and more. To ensure that each bolt stays in place for as long as you use the filter, Waterdrop has put together an integrated waterway design. This layout will also prevent water leakage and allow you to replace the system’s filters without having to cut off the water supply. The reverse osmosis system is entirely DIY, so you can install the whole thing in less than 30 minutes without using any tools. The RO system also features a handy filter indicator that allows you to check how much your filter’s capacities are used.

The reverse osmosis system’s innovative design doesn’t stop there, as it also prioritizes efficiency. The filter unit is entirely battery-driven, meaning that it doesn’t need an under-sink electric supply to run. Another critical hallmark is that this system doesn’t require water drainage, so you can have an endless stream of pure water without wasting a single drop. Its success rate is granted by its triple filter components, including a PP, CT, and CS filter. To replace the used filters, all you have to do is use the system’s twist and lock feature, which takes less than three seconds. Waterdrop is the victor of many prestigious awards, the most famous of which are the Red Dot and Dieline Awards. This reverse osmosis filter is currently rated at 4.7 (Amazon), which entails that the filter is both practical and reliable.

2. Aquasana Claryum Technology Under-Sink Filter ($142.85)

* Apply the “LS” discount code at the end of your purchase to get a discount of up to 50% *

Anyone who’s had an Aquasana filter before knows they mean business. The premium-grade manufacturer holds some impressive accolades for its legacy in the water treatment industry. Among the most relevant for our purpose here is the Best New Home Product, the Best of the Test, and the 2019th Company of The Year. Aquasana is also among the first US-based brands that tackled PFAS pollutants in water, so you can expect excellent water filtration capacities from the company.

The Aquasana product we’ve brought here is the under-sink filter system that utilizes a technology called Claryum. The innovative filter claims (and is proven) to reduce more than fifteen times as many water contaminants as a regular carbon-based filter. This is all thanks to its four-stage filtration, which we’ll discuss below.  

First, the under-sink filter begins by tackling sediment, silt, dirt, and other large particles that deteriorate your water quality. Sediment is most common in well water locations, but many people supplied by municipal sources have also reported bits of dust, rust, and silt in their waters. Don’t worry though, no matter where you’re residing, Aquasana’s 20-micron filter will go above and beyond to fix your water issue. In the second stage, the under-sink filter uses its activated-carbon mechanisms to reduce chlorine, hydrogen sulfide, VOCs, herbicides, pesticides, and chlorine-resistant cysts. The water filter then utilizes its catalytic carbon filters to reduce any remaining pharmaceuticals and PFOA/PFOS pollutants that are detrimental to ruining our water quality, harming our home appliances, and worsening our health.

Aquasana stands out from the competition because it features another filtration method that’s quite effective yet not commonly used. To reduce any remaining contaminants, this under-sink filter takes advantage of ion-exchange. Here, your water is cleansed from heavy metals like lead, mercury, and bacteria. Aquasana then takes this to another level, as the under-sink filter retains the necessary minerals like calcium and magnesium, so you’ll have fresh, clean, and mineralized water. The Aquasana filter is certified by the NSF for a 99% success rate at combatting these contaminants, so you can wholly trust its claims.

Like most under-sink filters, this system doesn’t require an electrical outlet, water drainage, or much effort with set-up, use, and aftercare. The 600-gallon water filter is currently rated by more than 1500 people, and it holds a 4.5 review score on the brand’s official website.  

3. APEC WFS1000 Under-Sink Filtration System ($139.95)

* If you buy directly from APEC, you can use the “MBFF25” code for a 25% discount *

Like Aquasana, APEC is renowned for designing affordable filter systems that ensure practicality with every drop. Such a device is the WFS1000 under-sink filter that holds about 1000 positive reviews and a 4.6 review score on Amazon. Like most local brands, APEC takes pride in the fact that all its systems are designed, manufactured, and put together in the US. APEC makes these filters last a lifetime, so you won’t have to think about buying a replacement when the system serves its purpose. The APEC filtration units can treat any type of tap water, but they mainly specialize in well water contaminants. For as long as you keep the unit in its best condition, APEC guarantees a limitless supply of clean water on demand.   

The main reason why you can put your trust in APEC is its NSF certification. The brand’s under-sink water filter is certified to reduce, remove, or alter more than 60 water pollutants, except TDS contaminants. The fast-functioning device can significantly interfere with the formation of chlorine, heavy metals, pesticides and herbicides, VOCs, and more. Like its predecessor, this water filtration system also features a multi-stage mechanism that starts with sediment filtering. After the PP filter, the water goes through a premium-extruded carbon block that turns your contaminated water into a colorless, odorless, yet tasteful fluid. The third water filter serves as the unit’s last line of defense, as it neatly removes any remaining contaminants from your water supply. Because the process is repeated many times over, there is little to no chance that you’re left with particles of your previously-polluted water.

On the brand’s official website, this system’s filters are labeled as “super capacity filters,” as they last for a whole year before you have to think about replacing them. This duration is also translated within the system’s warranty since APEC will aid for as long as one year after your initial purchase. The under-sink filter is also accompanied by lifetime customer support, granted by a WQA-certified water specialist. The filter system also comes with a complete lead-free plumbing fixture, including a sleek chrome faucet to enhance your sink. Like remineralizing filters, this clean water alternative will retain your water’s alkalinity, thus making your water taste better in the process. And, for every purchase you make with APEC, they will ship a payment over to communities where they have no access to clean water.  

4. Waterdrop 15UB Under-Sink Filter with Faucet ($79.99)

* For first purchases, Waterdrop offers a 10% discount with the code “WELCOME10” *

It would be unfair to Waterdrop to give it that much praise and not include its runner-up filter model that goes by the 15UB tag. Under-sink water systems usually use carbon-block filters to do their dirty job, but a reverse osmosis system is also utilized every once in a while. The Waterdrop 15UB filter does just that, only by mixing it with a different multi-stage system that will make your water a no-zone for contaminants. Every premium-grade component in this unit is authority-guaranteed, ensuring long-lasting, worry-free use. The under-sink filter is made out of entirely lead-free parts, which its WQA 372 standard assures. The filtration device is also certified by the NSF for removing several contaminants from tap water. 

Even though the contaminant-removal list is extensive, Waterdrop is most praised for tackling sediment, chlorine, heavy metals, VOCs, and other particles. However, what this water filter offers that others don’t is incredible efficiency. According to the brand’s measures, this under-sink filter will initially cost you about nine cents per day in the first year, and on all years after, you’ll only spend about 4 cents per day. Since the system itself is very budget-friendly and its filter replacements even more so, you can start planning your early vacation days right away. The Waterdrop filter system will also greatly reduce the number of single-use water bottles, which will be better for your pockets and healthier for your environment.

One of the most recurring Amazon reviews of this water filter is its simple installation. The water under-sink system currently holds an excellent 4.7 score, which we believe is concerned chiefly with the effortless use this unit entails. The DIY-friendly filter will only take about three minutes to install, and its filters, less than three seconds. The premium-grade filter also features a dedicated stainless-steel faucet, so you can use two plumbing fixtures for an easy switch between filtered and unfiltered water. The Waterdrop filter needs no electricity to run, maintains a high-speed flow rate, and fits just about anywhere. This system’s average filter lifespan surpasses 16,000 gallons, meaning that you can have all the tasty water in the world before you have to replace its filters. And when you do, you’ll have an incredibly healthy mineral source that’s full of calcium, potassium, and magnesium.

5. Alexapure Home Under-Sink Filtration System ($299.95)

* If you sign up on Alexapure’s newsletter, you will get a discount offer tailored for you *

Alexa, who’s the last contender for our top-five under-sink filter list? No true review guide would be complete without Alexapure, and we’ll tell you why. When we reviewed the brand, we saw that Alexapure stays true to its “pioneered for perfection” motto. The renowned company is usually pinned against big brands like Berkey and Brita, the only exception being affordability. Even though this under-sink water system is slightly pricier than the models we’ve checked out before, we believe it is worth investing a couple more bucks in. The fan-favorite filtration system is primarily designed for larger families or heavy-duty water consumption, as its dual-power capacity reigns a little over 1000 gallons. The system is straightforward to assemble, straightforward to use, and effortless to enjoy. 

Before we get into Alexapure’s multi-faceted approach to treating water, we’re pleased to know that this system reduces more than 200 contaminants from water supplies. Yes, this under-sink filter features an NSF-certified technology that eradicated almost every human-known water pollutant, both in city and well water supplies. To name some, we would have to mention heavy metals like lead, mercury, and chromium, VOCs, pesticides and herbicides, chlorine and chloramines, and everything in between. The Alexapure filter system installs directly to your cold water supply, which means that these impurities won’t have a chance to get through your tap. What many buyers loved about this under-sink filter was its seamless, quiet operation, which will take you through gallons of clean water without any noise.

Speaking of customer reviews, it’s worth noting that Alexapure holds a consistent 4.6 score on most of its products on Amazon. Much of these reviews consistent with praise, especially for the system’s on-demand regeneration cycles. Thanks to this feature, you won’t have to wait around for your filter, as the treated water will be the one waiting. The filter’s high success rate is also a worthy mention, and for that, we have WQA‘s certification to thank. As the brand’s manufacturers explain, this model has a 99.99% efficiency in reducing specific contaminants from water supplies. The Alexapure filter also features a P231 certification that ensures it can filter out harmful particles as small as 0.5 microns. If you want to check out the system’s entire contaminant-reduction list, you can do so on the brand’s official website

6. ProOne FS10 Under-Sink Filter ($370)

* Purchasing through this Social Labs code will grant you a discount of up to 20% *

Our next superstar is ProOne, who you may probably know by their old name – Propur. What started as a small, family-owned business quickly turned into a top contender for several awards, prices, and certifications. Like Berkey and Kube Water, ProOne makes some of the best gravity-led whole-house filters, but that’s not where we’ll focus today. The brand’s SF10 under-sink filter is the missing puzzle for many potential buyers, as it is long-lasting, sophisticated, and wondrously effective. The under-sink filter connects directly to your inline water supply, so not only does it filter out the contaminants on your water, but it ensures that your plumbing is in a tiptoe condition too. Because this unit is incredibly space-saving, you can utilize it on any well water system, tap water, RV, or other faucets in your home.

The main reason behind ProOne’s fantastic device is its ProMax, Full Spectrum filter. As the brand explains, this carbon-based filter employs an all-in-one solution to almost all water problems. On ProOne’s website, we could find a list of over 220 contaminants that the FS10 is certified to remove. If you decide on this model, you can kiss all herbicides, pesticides, heavy metals, microorganisms, VOCs, parasites, algae, and pharmaceuticals goodbye. The under-sink water filter also does a great job with chlorine reduction, as several independent lab results have shown that ProOne’s treated water is virtually spotless. As for its NSF-certifications, the FS10 proudly offers its ANSI 42, 53, P231, and 401 standards. If that’s not an impressive water filtration track record, then we don’t know what is.

If you’re a first-time buyer, investing in this water filter will give you the clear-cut solution you’ve probably been looking for. The system’s filters have an average lifespan of up to one year or 1000 gallons – whichever comes first. ProOne also favors the possibility of installing a second faucet so that you can switch between the two for ultimate water-conserving. This will give you an extra year to enjoy, but it will also come at a bulkier price. Because the FS10 requires no electricity, water drainage, or complicated settings, you can effortlessly install it. ProOne will include all the tools, mounting brackets, and lead-free fittings, which can also be used when replacing the unit’s filters. Unfortunately, ProOne doesn’t have a review section for measuring customer reviews, but it seems to be doing quite well on expert assessments. The FS10 also has a better performance than the competition, so it is pretty reliable as well.

7. Tier1 4-Stage Under-Sink Filtration System ($138.99)

* With the “SAVE15” code, you will get a 15% discount on Tier1’s official website *

If you want to buy from a brand that will offer you full customization for your water treatment device, Tier1 is the best way to go. Upon researching the company, we found that it offers some of the best water filtration choices to match your needs ideally. If you sign-up for an account on Tier1, you will immediately be asked to insert your living situation (for the water consumption rate) and water source (city or well water). This is especially favorable since many people go for “well-known” systems that won’t do anything about their water problem. However, we’re confident that the brand’s under-sink filtration system will suit several families at once, mainly because it is practical, reliable, and budget-conscious. 

To ensure that the contaminants in your water are taken care of properly, Tier1 features a four-stage filtration system to die for. First, the dirty water goes through a 5-micron sediment filter that takes out the large particles for the system to do its business properly. In the second stage, the Tier1 unit shows off its intensive water treatment plan by utilizing carbon-block filters that guarantee no water pollutant is safe. The water then enters an additional 1-micron sediment filter that deals with various leftovers from the first two stages. This is often where heavy metals, chlorine, and VOCs are targeted, as they contain filter-resistant components that need some effort to be extracted. In the last stage, Tier1 features a hollow ultra-filtration fiber that tackles smaller particles like herbicides, pesticides, and contaminants of the like.

Before we get down to the specifics, we must note that Tier1 is NSF-certified, so you won’t have to freat about its filtration abilities. Like most products showcased here, this water filter installs directly into your cold water supply. With a 1500-gallon filter life, the under-sink system will suit you, your family, and all your guests to supreme water quality. What’s quite interesting about this filtration unit is that it can also withstand a pressure range of up to 120 PSI and virtually no pressure drop. This means that you will have more or less the same water pressure you did before installing the device – which isn’t the case with most under-sink water filters. Because Tier1 fully believes in its expertise, it has launched all its products with a lifetime satisfaction guarantee. The brand also features a 30-day returns policy, so if you’re unsatisfied with the under-sink unit within a month, you can return it. 

8. Pelican 3-Stage Under-Sink Filter ($154)

* With the “Rev10” code, you will get a discount of up to 10% on Pelican Pentair * 

Here at Water Whizz, we have reviewed hundreds of water treatment products. Still, we can safely say that no best-of-list has ever been fashioned without including a Pelican product. We love the brand so much we gave it two reviews, one for its water softeners range and one for its water filters. Right now, we’re going to put all the spotlight on Pelican’s three-stage under-sink filter that can do wonders for your home, apartment, or RV. Compared to reverse osmosis systems that are pretty generous with water waste, Pelican’s system is incredibly efficient. The under-sink filter requires no electricity to run, has no drainage pipes, and only uses the least amount of water for treating your inline supply.

Pelican’s masterwork will accommodate most small to medium families, and it will produce up to 1,500 gallons of water with each filtration cycle. And, considering its price, we think that’s a real bargain.  

If you were impressed by the other systems’ 5-micron filters, you’re going to love Pelican’s 25-micron alternative. By tackling contaminants with microscopic sizes, the under-sink system ensures that its filters aren’t being wasted unnecessarily, which equals a longer filter life. After the contaminated water is rid of sediment, silt, rust, dust, and dirt, the system goes into a second stage that features a catalytic granulated activated carbon filter. Here, the filtration device deals with chlorine and chloramines, the main culprits in the water’s odd smell and flavor. This process is repeated on a second GAC filter, meaning that the water is thoroughly cleaned before it reaches your tap. The tap is precisely where the system stands out for many buyers, as Pelican features its own faucet that’s incredibly convenient.

Upon purchasing the under-sink filter, you can choose between three faucet finishes, chrome, nickel, or bronze. Whichever model you decide to go with, we believe that its installation, use, and maintenance will be a breeze. To take care of the system, all you have to do is take out the used filters and replace them with new ones every year. The filter’s twist and lock design will help you make this process effortless, so you can go about it without using any tools. The US-based water filter also ensures that all the beneficial minerals in your water are retained within it, so you will love the water you drink and feel better while doing so as well. This under-sink water filter currently has a 4.5 rating on Pelican’s website

9. Kube Advanced Water Filtration System (N/A)

* As soon as we find a discount code for the Kube filter, we will update it here *

We’re slowly going to the end of this list, and we can’t help but include an underdog that’s worth every penny (we are assuming!). While this under-sink filter doesn’t have an official price tag, its benchmark circles around $300. Kube Water is a unique product manufactured by the great Kinetico, which is why it doesn’t share more than it thinks it needs to without an official water test. Like most high-end companies, the Kinetico technicians insist that a proper water evaluation needs to be made so the best device can be suited and not the other way around. However, as far as reliability goes, Kinetico is more than a worthy opponent, and you can hardly go wrong with it.

Since its creation, the brand has received several prestigious awards, including the Best Buy ribbon from Consumables Digest, Build It’s Best Plumbing Device and the Most Efficient Badge by the Water Quality Association. 

What makes this under-sink water filter ideal for you is mainly the practicality with which it comes. The water filtration device has a dual-filter cartridge, meaning that it will process twice the amount of water than regular water filters. Its activated-carbon filters are NSF-certified to reduce chlorine, lead, MTBE, mercury, VOCs, and water cysts. The under-sink filter has a capacity of 1,800 gallons per filter, which will give you a year and some change to treat your water. The premium-grade filter can sustain a pressure of up to 125 PSI, so you won’t notice the water flow change after you install the device. The Kube water filter employs a very compact-sized layout so that you won’t experience any hassles with placing it under the sink and inside your cupboards. The Kinetico system also weighs less than seven pounds and is effortless to set up, so you can try all the faucet fixtures in your home with it. 

Like most high-sustaining brands, Kinetico also ensures that you have an endless supply of clean water, whenever you need it, without any restrictions. The filter cartridges in this unit are neatly secured into the system, so you won’t have to worry about inefficient spending or water leakage. The Kube water filter also features a convenient bypass valve that will come in quite handy when you go all Bob the Builder into your water system. Whenever you need to adjust the device, you can switch the valve and deal with your system without shutting off your entire house’s water supply. This under-sink filter needs no electricity or drainage, and it will cost you about four cents per month. The filter system comes with a two-year warranty and a 30-day money-back guarantee, so test it out and decide for yourself.

10. Hydroviv Under-Sink Water Filter ($179.99)

* With the “BLEM” code, you can get a discount of up to 50% on selecet filters *

For the cherry on top of the cake, we decided to go with Hydroviv’s tailored tap water filter that guarantees to optimize your water quality. Like Tier1, this manufacturer will ensure that the filter of your choice will fully match the conditions in your living area. When you sign up for an account, Hydroviv will take your provided location and suggest the proper filters that combat the contaminants present in your city water. This simple yet effective filter tailoring method is quite appreciated by the brand’s buyers, considering that this product currently has a 4.9 review score.

Hydroviv’s premium product can also remove up to 99% of PFOAs, which, according to them – are never treated properly by the competition’s water filters.

While we like to keep an open mind about other brands’ filtering capacities, Hydroviv makes a very compelling case for itself. Compared to world-class companies like Pur, Brita, Berkey, and Whirlpool, Hidroviv has the best efficiency rates for dealing with PFOAs. This under-sink water filter is also certified by the NSF for removing several other pollutants like lead, mercury, arsenic, VOCs, cysts, pesticides, herbicides, chlorine, chloramines, and a bunch of other abbreviations that will just bore you. What matters is that Hydroviv knows what it’s doing, and it does a fantastic job while at it. Like most high-performing devices, this under-sink system also features an activated carbon filter that does wonders for city and well water.

To compel its potential buyers into purchasing this unit, Hydroviv also states that installing it takes less than 15 minutes. That’s a hallmark we can wholeheartedly believe since the under-sink filter has an efficient design and easy-to-use controls. That means that you will save some extra bucks from hiring a professional plumber and have some DIY time alone with your tools.

The brand has also put together a handy installation video so that you can say farewell to any potential head-scratching too. Most of the 500 customer reviews praised the system’s performance, ease-of-installation, efficiency, and water quality. To ensure that your purchase comes with peace of mind, Hydroviv has attached a five-year warranty and a 30-day money-back guarantee, so go ahead and put down an offer right away.  


Related Topics To Read Next

Best Countertop Water Filter

Best Shower Filter

Best Reverse Osmosis System

Best Faucet Water Filter

Best Whole House Water Filter

Best Water Filter Pitcher

About the Author Clark Robinson

Clark has always been involved in water supply system. If you have any questions you want to ask him personally, you can reach him at clark@waterfilterwhizz.com