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11 Best Under Sink Water Filters of 2021 – Reviews & Buying Guide

If you or your family drink a lot of water, you would probably benefit from an under sink water filter.

Why?

Because filter jugs and other countertop or refrigerator filters just don’t hold enough water if you drink more than a couple of liters a day. And whether you live alone or with scatter-brained teens, you will definitely have come to the kitchen some time to get a nice cool glass of filtered water and found your filter jug empty. 

An under sink filter means that all the water that comes from the faucet it’s attached to (usually the kitchen sink, but some under sink filter lovers add one to bathroom sinks too) is freshly filtered and ready to enjoy.

Why You Need an Under Sink Water Filter

Having an under sink filter is just easier! Many of the options on this list are really affordable and can be installed DIY if you’ve ever held a wrench.  

And once you’ve spent a few minutes plugging your new filter in (or persuaded/paid someone to do it for you) you simply don’t need to think about it again for six months, a year, in some cases longer.

In short, it will save you time and energy. An under sink water filter will also make sure your whole family drinks filtered water - yes, even if your kid comes in from playing soccer and drinks straight from the faucet they’ll be slurping up filtered water!

In addition to that, an under sink filter makes it easy to use filtered water for cooking, cleaning and even doing the dishes. Can you imagine doing all that with a filter jug? You’d need quite a lot of them, and you would look very strange washing carrots or mopping the floor jug in hand!

Whether you just filter your water to get the best possible taste and smell, or you want to remove contaminants like chlorine, lead and rust, or even heavy metals, there’s an under sink water filter on the market that suits your needs.

1. Home Master TMAFC-ERP

The Home Master TMAFC-ERP is a full-contact reverse osmosis water filter system. It’s US made, and NSF certified.

Home Master TMAFC-ERP

Pros

  • A great mid-range option
  • A pump ensure that the flow of your water remains fast
  • Includes remineralization
  • The Home Master promises reduced water waste
  • Filter changes should only be needed annually

Cons

  • More complete/advanced packages bump up the price
  • RO systems leaching minerals is an issue in itself

The system consists of three distinct filters - a spun poly sediment filter, a catalytic carbon filter, a coconut shell granular activated carbon water filter. As this is a reverse osmosis or RO system, it uses pressure to remove contaminants. In doing so, the mineral content of the water is reduced.

But don’t worry! The Home Master includes a patented remineralization system to add calcium and magnesium to the water not once but twice during filtration. This not only means you’re getting what is essentially mineral water on tap, but it helps your under sink filter to last longer because the minerals protect against degradation.

This system promises to remove up to 99% chlorine, chemicals, metals, fluoride, TDS, pharmaceuticals, microplastics, amongst other things. It comes with a 5-year warranty, and with an all-in-one modular design it comes ready for DIY installation. 

Bottom Line

The Home Master is a great midrange RO all-rounder, and the remineralization system is second to none.


2. APEC Water Systems ROES-PH75

This system guarantees the removal of 99% of contaminants like chlorine, VOCs, as well as toxic fluoride, arsenic, lead, nitrates, heavy metals, and any bad tastes or odors. It also promises a water pressure of 40-85 psi.

APEC Water Systems ROES-PH75

Pros

  • This is a good value system
  • The APEC can purify more water daily than most comparable systems
  • Mineral quality is very important to APEC
  • The filtration process is very thorough

Cons

  • The waste water ratio, at 3:1, may simply be too high for some potential users
  • 60 minutes is quite a long DIY install time

The APEC can produce a whopping 90 gallons of pure water per day, which is the most of any 4 RO system I know of. 

The first filter in the system captures bigger particulates. After that, two large carbon block cartridges within suitable housing ensure maximum possible contact time between the filters and your drinking water as they get rid of chlorine and any weird tastes and smells.

Next is the high-rejection TFC RO membrane, which deals with heavy metals amongst other things, and finally a third coconut shell carbon filter to remove any strange flavors or smells picked up during the purification process itself.

This is all coupled with an alkaline filter to ensure delicious, contaminant free alkaline drinking water is available every time you turn on your faucet. 

Of course, with a system this advanced you also get remineralization. APEC are particularly proud of their remineralization technology, which does more than just throw calcium and magnesium at the standard RO demineralization issue. Instead, their remineralization cartridges add a carefully calculated level of US produced calcite.

It takes about an hour to install the APEC ROES-PH75 if you’re vaguely competent with a screwdriver, etc. If that sounds daunting or just boring, a plumber or handyman will be able to install it very easily. 

Bottom Line

If high-quality mineralization is something you value, and you don’t mind the somewhat larger than average 3:1 waste water ratio then this is a solid choice of under sink water filter.


3. Clearly Filtered 3-Stage Under Sink Water Filter System

Clearly Filtered have designed their neat 3-stage under sink water filter system to deliver filtered water instantly from your existing faucet. The system claims to remove up to 99% of 232 contaminants, including fluoride and lead.

Pros

  • The best option for renters
  • Extremely easy installation, removal, and filter changes
  • Avoids reverse osmosis, keeping minerals in your water
  • No bone char is used
  • A slim system that will fit under any sink

Cons

  • Not the cheapest option, but you may well save money in the long run

The real joy of this filter, though, is that installing it is incredibly quick and easy. It takes an average of 15 minutes but has been managed in much less time too! It can be uninstalled just as easily, making it a great option if you rent your home and a move might be in your mid-term future. 

Additionally, changing the filter cartridges in the Clearly Filtered 3-stage is a doddle - and videos are provided on the company’s website for both installation and filter changes, so you don’t have to scour Youtube to find a guide. 

Filters have a 2000 gallon life, which is pretty standard and means changing the cartridges every few months (which as I’ve mentioned is really easy - just make sure you have enough spares in the house when it’s time to change them).

The three stages of filtration within this system are as follows: 

The primer filter is granulated coconut-carbon, and gets rid of nasty tastes, cloudiness, odors, chlorine and VOCS amongst other common chemicals.

Filter two is a special blend filter which removes heavy metals, herbicides and pesticides, PFAs and more.

Bottom Line

If you don’t own your home, or you do but moving is on the horizon, then this high-grade traditional under sink filter with its easy install and uninstall feature is probably perfect for your needs.


4. Claryum 3-Stage

The Claryum 3-stage reduces or removes up to 77 contaminants, plus rust and sediment. With a 600 gallon life to each of its filter cartridges, they only need to be changed roughly every six months.

Pros

  • As this is not an RO filter, your water keeps its mineral content through the filtration process
  • The filter change reminders are a nice touch
  • Auto-delivery of filter cartridges could prove very useful
  • Top value for money
  • Faucet included

Cons

  • Somewhat complex to install
  • 600 gallon filter cartridge life is less than some competitors

As this is not an RO filter system, natural beneficial minerals like calcium, magnesium, and potassium are left in your water.  This means that your filtered water retains all its natural health benefits, but any dangerous contaminants are removed and it has a guaranteed fresh taste and smell.

The Claryum system is made up of a 20-micron pre-filter, an active carbon filter, and an ion-exchange filter. In tandem, these three filters reduce mercury, chlorine-resistant cysts, herbicides, pesticides, VOCs, pharmaceuticals and chlorine. The 3-Stage is NSF and ANSI certified.

The environment is also taken into consideration with this system, and it has minimal disposable plastic parts within its filters and filter casings. 

Filter change is easy, with a simple twist-off cap to each filter housing. Plus, the Claryum 3-Stage alerts you when it’s time to change your filters, so there’s no guessing-game or repeated water tasting required! Plus, with Clarium’s auto-delivery option for fresh filters, you’ll always have one (or three) on hand when needed. 

This system comes with a faucet included, and as you have to fit that faucet you do need at least rudimentary DIY or plumbing skills to install the 3-Stage. 

Bottom Line

If you want a classic under sink filter, but don’t want the faff of a reverse osmosis system, the 3-Stage from forward-thinking Claryum is probably the under sink filter of your dreams!


5. Pelican 3-Stage Drinking Filter

One of the draws of the Pelican 3-Stage is that it doesn’t waste water, which can be a problem with some under sink systems. Taking green design further, the Pelican also ships with minimal packaging, and is designed to be small and have no unnecessary parts, minimizing plastic use in its construction.

Pros

  • No water wastage and minimal use of plastics makes this system relatively environmentally friendly
  • Comes with a 1-year warranty
  • Avoids the issue of RO systems sapping minerals from water
  • Faucet included with system
  • Great value

Cons

  • The faucet options may not be to everyone’s taste
  • Requires professional installation unless you’re quite handy

The system features 25-micron pre-filter and two catalytic GAC carbon filters that use premium activated coconut carbon. The casing is also compact making the whole system really easy to fit under sinks of any size, and the roughly yearly maintenance routine of replacing the three filter cartridges is easy. Just remove the cover and replace the cartridge, no mess and no tools needed.

Water pressure should remain between 40-80 psi when you have a Pelican 3-Stage Drinking Filter installed, and the whole thing has a 1-year warranty in case of any teething problems or more serious issues. 

Relative to some competitors, the Pelican is quite easy to fit. It comes with an install kit that includes color-coded fittings to speed up the installation process, but as you have to fit a faucet you do need to be reasonably handy if you aren’t going to call in professional help. The faucets are available in brushed chrome, brushed nickel and copper, so you should be able to find at least an approximate match to your current decor. 

This system is made in the USA using skilled labor, with a mind to environmental sustainability. 

Bottom Line

If you’re looking for an under sink water filter you can feel good about using, get yourself a Pelican 3-Stage.


6. iSpring RCC7AK 6-Stage Under Sink Filter System

This is definitely the reverse osmosis system under sink filter for anyone with an eye for a bargain.

iSpring RCC7AK 6-Stage

Pros

  • Amazing value for an RO system
  • Built-in alkaline remineralization filter ensures lovely soft water
  • iSpring are making it as easy as possible for you to install DIY, with videos and clear instructions
  • NSF and ANSI certified

Cons

  • As with all RO systems, over-treatment of water is a concern
  • Water waste is a concern with all RO systems, but if you pay for your water it may be even more of a concern as it could ramp up bills

Despite a low price point, the iSpring RCC7AK boasts 6 filtration stages that not only remove 99% of contaminants like chlorine, lead, arsenic, and asbestos, but also softens and remineralizes your water. 

The six stages of this system include three pre-RO stages - a PP sediment filter, a carbon KDF filter, and a carbon block filter. They remove large particulate matter and chemicals like chlorine, all of which would damage the reverse osmosis filter. 

The reverse osmosis filter uses pressure to remove pretty much everything bigger than a water molecule. Finally, a granular activated carbon filter removes any tastes or smells that may be left in the pure water that has come through your filtration system, and your water is ready to be remineralized and softened. The Alkaline Remineralization process ensures your water is packed full of healthy minerals, and is gentle and alkaline rather than acidic and tough on your clothes, surfaces, skin and stomach.

This filter system is NSF and ANSI 58 certified, and comes with extremely clear DIY installation instructions. It also comes with a kitchen faucet, which, as with many of these filter systems, is quite stylish though it may not completely fit with your current kitchen aesthetic.

iSpring have their own technical videos available through their website, as well as great customer support available online or on the phone. 

Bottom Line

If you thought you couldn’t afford an RO undersink filter system, surprise, you can! And its the iSpring RCC7AK!


7. Home Master TMHP HydroPerfection

This is a high-end reverse osmosis system that also uses UV light to kill bacteria and mico-organisms and deliver you the freshest, healthiest water possible right from your faucet.

Home Master TMHP HydroPerfection

Pros

  • More environmentally friendly than most RO systems, with 80% reduced water waste
  • An unusual feature, the UV chamber is none the less practical
  • The remineralization process here is quite nuanced
  • Built-in alkalisation process to leave you with soft, alkaline water
  • An amazing 9-stages of filtration, purification and enhancement

Cons

  • This is a high-end system, with the price tag to prove it
  • There’s a possibility Home Master have over-egged the pudding with all the features
  • Additional features complicate installation and upkeep

The HydroPerfection offers 9-stages of filtration, purification, and enhancement. This allows the system to remove up to 99% of chlorine & chloramines, chemicals, lead, heavy metals, fluoride, microplastics, and more. 

After water has been filtered by the HydroPerfection it enters a UV sterilization chamber, which kills germs and viruses without changing the composition, flavor or temperature of your water.

Finally, Home Master uses a patented full contact artesian remineralization process to rebalance the PH of your water to a gentle alkaline level (twice, in fact) while enhancing it with small amounts of calcium and magnesium. 

This is a system that was designed to deal with some of the issues RO systems are usually called up for. For example, a built-in pump means that the HydroPerfection reduces water waste by up to 80% compared with its competitors, and it doesn’t need electricity to do it! It also claims to maintain the flow rate of your water, and almost never leak. This is backed by a 5-year warranty.

The HydroPerfection comes with a quick-release faucet that can be added to your existing sink set-up and used for washing fruits and vegetables, drinking, washing hands, and cooking. The system does need to be plugged into an outlet as well as being plumbed into your sink, and though it is possible to install the HydroPerfection DIY it would also be an easy job for a handyman or plumber.

Bottom Line

If you want all the bells and whistles under sink water filter system, including environmental credentials, then you could certainly do worse than the HydroPerfection. The UV sterilization chamber is a particularly nice added touch!


8. CuZn UC-200 Under Counter Water Filter

The CuZn has an amazing 5-year working life, backed by a 5-year warranty. The company promises to replace any system that gives up before five years has passed, as long as that system has been used as instructed and on municipal rather than well water.

CuZn UC-200 Under Counter Water Filter

Pros

  • A very simple, great value option
  • Easy to install
  • No upkeep
  • No water waste
  • 5-year warranty

Cons

  • Lacks the additional features of some of its competitors
  • It’s a simple system - this could be a pro or a con!
  • Due to its simplicity, this is probably not the filter for water that would otherwise be dangerous to drink

Although it’s smaller than most under counter water filter systems, the CuZn offers 3-stage filtration, including a micro sediment layer, activated coconut carbon, and a powerful KDF-55 filter. 

The first stage catches small particulate matter, the second deals with bad tastes and odors in your water, and the third reduces levels of lead and heavy metals amongst other things. The CuZn UC-200 has a bacteriostatic coating, meaning that it is not susceptible to mold or bacteria growth.

This is one of the easiest to install under counter filter system options on the market. You simply turn off your water, disconnect the cold water line beneath your sink, and insert the CuZn UC-200. 

There is no upkeep on this filter - rather you replace the unit every five years (or when chlorine test strips show the presence of chlorine in your tap water). With its very reasonable price, replacing the unit every five years should still work out cheaper or as cheap as other leading under sink water filter models, as beyond the initial outlay you also have to purchase replacement filter cartridges for most of them.

Bottom Line

If you want something really simple, and you would like to plumb it in and forget about it, get yourself the CuZn UC-200.


9. Frizzlife Under Sink Water Filter System

The Frizzlife is another simple under sink water filter system that can be very quickly plugged into the water line of your kitchen faucet, your bath, or even your fridge’s ice maker! I mean, what’s the point of drinking filtered water if you put unfiltered ice in it?

Frizzlife Under Sink Water Filter System

Pros

  • Very good value
  • Easy to install
  • Easy to upkeep
  • A great option if you want to install additional filters in your home when you have your kitchen faucet covered
  • Leaves minerals in your water

Cons

  • Not the most hardy or best looking bit of kit
  • Does not deal with heavy metals

The 2-stage filter removes 99% of lead and chlorine, and sediment from your water, as well as improving the taste and smell of your water. The first stage is a sediment filter with 5-micron precision, and the second is a block carbon filter with 0.5 micro precision. 

This system does not remove heavy metals, so if that’s an issue for you (for example, if you live in an older and unrenovated property or use well water in your home) then you should look elsewhere.

Along with being very affordable at point of purchase, the Frizzlife is very economical in terms of upkeep. New filter cartridges are very economical, and changing them is easy. Just unscrew the top of the Frizzlife canister and swap the cartridges out. You don’t even need to shut off your water, as there is a bypass option. 

As it’s just a carbon filter and sediment filter, this system leaves all the healthy minerals in your water where they are. That means there’s no complex remineralization process, and your water will be roughly the same PH it usually is.

Bottom Line

If you’re looking for a cheap and cheerful solution to water that smells or tastes bad - or you just want a simple filter for your ice maker - the Frizzlife Under Sink Water Filter System might just be perfect for your needs.


10. Waterdrop 10UA Under Sink Water Filter System

Another simple, excellent value option is the Waterdrop 10UA. This under sink water filter system plumbs straight into your cold water line using innovative and easy to use push to connect fittings. So, a minimal toolbox shouldn’t be an issue!

Waterdrop 10UA Under Sink Water Filter System

Pros

  • Amazingly good value
  • Very easy to install, even if you aren’t practically inclined
  • The 10,000 gallon filter life means installation is a breeze
  • Deals with heavy metals through its KDF filter
  • Retains mineral composition of your water

Cons

  • It’s a very simple system, so might not be to everyone’s tastes
  • Wouldn’t work for well water, or other heavily contaminated water sources

Once plumbed in (which the company claims takes 3 minutes, though I would definitely allot myself at least 10) the Waterdrop doesn’t affect your water pressure, promising a psi of 60.

Replacing the filters is just as easy, and takes only seconds, but you won’t have to worry about that often as this system’s 10,000 gallon filter life mean you’ll only have to change the filter every 6 to 12 months. 

Given its low shelf price and minimal upkeep, this is a fantastic budget under sink filter system option. Plus, as it can be installed and uninstalled easily leaving no trace that anything has been changed, the Waterdrop 10UA is another great option for renters. 

This system includes a sediment filter, and active carbon filter and a KDF filter, so it deals with sediment and rust, chlorine, lead, odors and unpleasant tastes, and even heavy metals. It doesn’t filter out any essential minerals, leaving your water as rich in potassium, calcium, magnesium and sodium as it was before filtration.

Bottom Line

This is a genuinely well-designed budget option that ticks all the boxes and won’t drive you made with a tricky installation. It’s a perfect starter filter, and a great option for renters.


11. APEC WFS-1000

This premium, high-performance 3-stage under sink water filter system from APEC is US made, with high quality components and a larger than average filter size to ensure easy upkeep.

APEC WFS-1000 3 Stage Under-Sink Water Filter System

Pros

  • Good value
  • This is an environmentally friendly option as no water is wasted
  • The mineral content of your water is undisturbed
  • Improves taste/smell of water
  • Made in the USA
  • Cartridges only need to be replaced approximately every 12 months

Cons

  • Does not deal with heavy metals
  • Complex to plumb in considering the simplicity of what it does

Filters have to be changed approximately once a year, meaning you don’t have to think much about your APEC WFS-1000 once it’s plumbed in. The system comes with a faucet, so some knowledge of plumbing and DIY is required to install it. It also comes with a 1-year warranty, and promises a clog-free experience along with no water wastage.

The filters are as follows:

First is a high-capacity polypropylene sediment filter which removes dust, dirt, rust and other particles.

Second comes an extruded carbon block filter which removes chlorine, cloudiness, VOCs, unpleasant tastes, and more.

Finally, a second carbon block filter further purifies your water. 

The whole filtration process is quick, meaning that water will flow from your faucet as soon as you turn it on, with good water pressure maintained (up to 85 psi).

The APEC WFS-1000 system does not remove heavy metals, so is not suitable for use with well water or any other water that might contain them. It removes chlorine, sediment and VOCs, and improves the taste and smell of your water to make it not only palatable but irresistible! It also maintains the mineral balance and existing PH of your water.

Bottom Line

If you’re looking for a well-constructed, American made under sink water filter then try this offering from APEC.


Guide on How to Choose the Right Under Sink Filter 

The two main types of under sink filter are reverse osmosis filters and conventional filters, with a third option of ultra simple under sink filters.

Here’s a short explanation of each, including their pros and cons. 

1. Reverse Osmosis Filter

A reverse osmosis filter uses pressure to force water through a semipermeable membrane. This membrane is so fine that only water molecules can get through, leaving all contaminants behind.

This process is often combined with the various filter types used in a conventional filter, which in a modern reverse osmosis filter are used as the prefilter stage. 

Reverse osmosis filters get rid of more contaminants than any other filter type, but they have two issues.

Firstly, when I say everything I mean everything. That means that minerals and beneficial chemicals like low levels of fluoride are removed from your water along with contaminants.

Secondly, reverse osmosis filters use a lot of water and most of it is simply flushed down the drain. The process produces one gallon of water using one or two gallons to process it which are then flushed. That’s not very environmentally friendly, and if you’re billed for water it can really add up.

The first problem can be solved by a remineralization process, which is sometimes paired up with a process that gives you gently alkaline water. This means your tap water is chock-full of beneficial minerals, but it also means you have to buy mineral cartridges along with filter cartridges and change them regularly.

Unfortunately, there really is no solution at present for the water wastage issue. If you have an eye on the environment or on your own wallet, an RO filter might not be the smartest choice for your needs. 

2. Conventional Filter

Conventional filters utilize sediment filters, carbon filters and KDF filters to remove, respectively, dust, dirt, sand and rust, chlorine and bad tastes and smells, and heavy metals. This is a pretty complete filtration process.

Usually, these filters are housed separately and various flow design methods are employed to ensure a decent level of contact between your water and each of the filters. This can slow water down a little when you first turn on your faucet, but usually pressure is maintained or near-maintained overall.

These filters often come with a faucet, and are reasonably easy to plumb in if you have an okay knowledge of DIY. 

3. Simple Filter

Simple filters are… well… simple. You simply clip or screw them into your cold water line and your water supply flows through them and comes out of your existing faucet. When you remove a simple filter, you simply reconnect the cold water line leaving everything as it was before.

These filters really vary in their specifics. There was a time when they were really minimal, and mostly existed to make unpleasant tasting water more palatable while not actually making it any safer to drink, but in recent years they have become more advanced. 

In fact, the Waterdrop on this list is a simple filter that provides exactly what an average conventional filter usually provides, including a KDF filter for heavy metals.

If you’re a renter, or don’t have a lot of money to play with then look into simple filters. These are also a great option for an office or break room, or anywhere where water flavor is the biggest concern. 

Final Thoughts

Personally, I’m quite environmentally minded so I tend to avoid reverse osmosis filters. And yet, I know plenty of people who swear by them! If that sounds like you, then I’d recommend either the iSpring (as a very good budget option) or the Home Master HydroPerfection. The latter is about as advanced as an under sink water filter can get - the UV chamber in particular is a feature I haven’t seen anywhere else. And yet it’s a really useful one!

Something I really appreciate about the under sink filter market right now is its breadth. There are options for every budget and every situation. I love the neat, environmentally conscious Claryum 3-stage, and I’m equally taken by the stylish, slick and extremely affordable Waterdrop. For me, as a renter, it’s between these two systems, and I think the Waterdrop’s ease of installation and price just pushes it over the finish line to become my favorite from the list.

Of course, your pick is probably different. If you have a larger family, for example, you’re going to want something that can deal with a real high rate of use. And if you’re dealing with particularly contaminated water, perhaps you’ll be springing for that UV chamber!


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