11 Best Under Sink Water Filters – (Reviews & Guide 2021)

Under sink water filters are now more efficient than ever. Some of the contaminants previously removed from the water only with the help of reverse osmosis systems are now being blocked by these filters.

But did you know that unlike reverse osmosis systems, under sink filters don’t produce any wastewater?

In the following article, we present the most efficient best under sink water filters of 2021. Not only do we discuss their pros and cons, but we also explain why using an under-sink filter is an efficient way of producing fresh drinking water for you and your family.

We’re certain that after reading our under sink water filter reviews you’ll be able to make an informed decision about which model is best for your household. These are efficient filters, and they’re also more environmentally friendly than other filtration solutions.

Best Under Sink Water Filters Comparison Chart

iSpring 4-stage Under Sink Water Filtration System

iSpring CU-A4 4-stage Under Sink Water Filter

It removes most problematic contaminants while maintaining a natural alkaline balance and great tasteView on Amazon
Pelican 3-stage Under-Counter Drinking Water Filter

Pelican 3-stage Under-Counter Drinking Water Filter

The Pelican 3-Stage Drinking Filter offers high quality drinking water by reducing chlorine and chloramine taste/odor from your water.View on Pelican

Aquasana AQ-5300.55 3-Stage Under Sink Water Filter System

Drink high-quality drinking as this unit will remove most of the contaminants in your drinking water, including chlorine, pesticides, herbicides, heavy metals, and VOCs.View on Aquasana
Waterdrop 15UA Under Sink Water Filter System

Waterdrop 15UA Under Sink Water Filter System

The Waterdrop Filtration System works without electricity and doesn’t produce waste water, thereby reducing the amount that you spend on electricity and waterView on Amazon
Clearly Filtered Kitchen Faucet Filtration System

Clearly Filtered Kitchen Faucet Filtration System

Your tap water will be filtered to remove up to 99.9% of 232+ contaminants.View on Clearly

CuZn UC-200 Under Counter Water Filter

This unit doesn’t need an additional faucet, unlike other under-sink filters. This feature makes it very easy to install.View on Amazon

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

Drink high-quality water with this unit’s 3-stage filtration process, which removes most of the contaminants in the water.View on Amazon
Frizzlife Under Sink Water Filter System

Frizzlife Under Sink Water Filter System

This filtration system is so precise that it can remove particles as small as 0, 5 micronsView on Amazon

Best Under Sink Water Filter Reviews (Updated List)

1. iSpring CU-A4 4-stage Under Sink Water Filter

iSpring 4-stage Under Sink Water Filtration SystemGiving you an excellent bang for your buck, this under-sink water filtration system definitely surpasses expectations. The CU-A4 unit will provide you with a 4-stage filtration of your water, and it even features a 0.1-micron ultrafilter to make sure that 99% of all contaminants are gotten rid of.

Speaking of contaminants, all sediment and dirt will be eliminated together with most heavy metals, pesticides, chloramine, and arsenic. You will have odorless water ready for cooking and drinking. Yes, fluoride is not removed, but this is rarely a deal-breaker.

Installation of the set happens quickly and with little effort. The fittings are of the snap-on type, and this doesn’t require any tools. The best part is that you can also have your fridge connected to the under sink filter and enjoy clean water from more than one faucet.

The set will come with the 4 cartridges and a stainless-steel faucet. You will not need to detach any water lines to get the system in place.

Mind the unit’s size because you have to have enough room under your sink to fit all 4 cartridges. You can’t have one of them missing because the unit will not function. Replace filters once every 6-12 months.


  • No compromises are made with the effectiveness of the filter. It will get rid of 99% of contaminants.
  • Removes sediment and heavy metals. This makes it excellent if you use well water.
  • Can be connected to a fridge
  • The system is NSF/ANSI certified
  • 24/7 customer support is at your disposal


  • The manufacturer’s warranty is only 1 year.
  • Fluoride is not filtered out.

Read More: iSpring CU-A4

2. Pelican 3-stage Under-Counter Drinking Water Filter

Pelican 3-stage Under-Counter Drinking Water FilterHere we have a 3-stage under sink water filtration system that comes with everything you need. The Pelican unit has 3 cartridges, 2 of which are GAC filters. They ensure thorough filtration of your water with significantly reduced levels of chlorine and chloramine.

The first stage of the system, however, is the 25-micron pre-filter. It is excellent when it comes to the removal of larger particles such as debris and sand. You definitely need this cartridge if you use well-water.

You can expect the filters to last anywhere between 6 and 12 months. Unfortunately, there aren’t any indicators to tell you that the filters require a change. The best part is that the system barely requires any maintenance and cleaning. You only need to replaced the filters.

Calcium and magnesium will remain in your drinking water which means that it will not be softened. According to some people this is an advantage. The unit is made in the USA and is backed by a 1-year warranty.


  • Comes with everything you need – faucet, fittings, installation guide
  • Filters last 1500 gallons or about 1 year
  • The 3 stage filtration ensures clean and odorless drinking water


  • The warranty could have been longer

3. Aquasana AQ-5300.55 3-Stage Under Sink Water Filter

Aquasana AQ-5300.55 3-Stage Under Sink Water Filter SystemThis is one of the budget choices we included on our list. Despite its cheap price, this water filter is capable of producing clean and crisp water, just like the more expensive models.

The Aquasana under sink filter is highly effective. It will remove most of the contaminants in your drinking water, including chlorine, pesticides, herbicides, heavy metals, and VOCs.

One of the advantages of using this water filter is its twist-off design. Once a water filter needs replacing (about once every 6 months) you will only have to twist it off and twist the new one on. The filter change will only take up to 5 minutes, so that’s a big plus.

Another advantage is that this filter comes with a good faucet. Not only that, but you can actually change the faucet’s finish when you buy the filter, so it will match the rest of your fixtures.

  • Pro:
    Filter Change Notification – You won’t have to guess when the filters need changing if you’re using this model. The system will notify you when the old filters have to be changed.
  • Con:
    Poor O-rings – This filter comes with poor O-rings. The rings will fail after 2 or 3 years of use. However, the company will send you new ones if you contact them.

Read More: Aquasana AQ-5300.55

4. Waterdrop 15UA Under Sink Water Filter System

Waterdrop 15UA Under Sink Water Filter SystemHere we present to you a fairly affordable under sink water filter, which just may exceed your expectations. The cool part is that the cartridge is only one, but the water filtration happens in 5 stages. Unlike other systems where you will need to install 2-3 cartridges for each stage, here you have some space economy.

The WD-15UA will get rid of heavy metals, which include lead and mercury, will remove fluoride (activated alumina is the medium that does this), and render your water 99% chloramine-free. Thanks to the activated carbon block, the water will have an improved taste, and it will be odorless.

Another advantage is that you do not need to have a separate faucet for this system. It connects straight to the existing faucet in your home. You can, of course, install a separate faucet if you want, but you will need to purchase it in addition to the system.

Unfortunately, the product will not indicate when a filter replacement should take place. You have to monitor that yourself. The WD-15UA should have a lifespan of about two years or 16,000 gallons before a filter change is required.


  • Does not require a separate faucet to connect
  • The system works perfectly with well water because it removes heavy metals. Effective in the removal of chloramines
  • It can be set up for off-grid living. The system does not require electricity.


  • Cannot be used with hot water
  • There is no way to track when a filter change is due.

5. Clearly Filtered Kitchen Faucet Filtration System

Clearly Filtered Kitchen Faucet Filtration SystemHere we have a top-notch under sink water filter that is good for both homeowners and renters. The installation is so easy that a child can handle it. You only need to connect the water lines and that’s it. A slight drawback here is that the filter doesn’t have a bypass valve and every time you turn on the cold water, it will go through the cartridge.

The unit removes over 220 known contaminants and this includes chlorine and fluoride. The technology of this filter allows it to produce tasteless and odorless water which is perfect for cooking. The system is EPA, NSF certified, and is 100% American-made.

The filter life is about 1 year (give or take) which is decent but there’s no indicator of when a replacement is due. You can install this system horizontally and not only vertically. The connection size is 3/8 inches. You also get a lifetime warranty from the manufacturer.


  • Long filter life – it will last for about 12 months
  • Compact – you can easily mount it and unmount it
  • Thorough filtration – your water will be free of over 220 contaminants
  • No need to purchase a faucet – just connect the existing water lines


  • No bypass valve – the filter will be almost always in use
  • There’s no sound or light indicator to prompt you to replace the filter


6. CuZn UC-200 Under Counter Water Filter

CuZn UC-200 Under Counter Water FilterThis is one of the highest-rated products on our list. After taking a look at what it does and correlating that with how much it costs, it’s easy to understand why this model has such high ratings.

First of all, the major advantage of using this water filter is a good and easy installation process. Unlike other under-sink filters, this one doesn’t need an additional faucet. It will connect directly to your sink’s cold water line instead. The filter also comes with all the components you need for the installation.

Another advantage is the long-lasting filter it uses. This under sink filtration system uses a filter capable of producing up to 50,000 gallons of filtered water. Most people will filter this volume of water in about 5 years, so it’s safe to say this filter lasts more than others.

  • Pro:
    Simple Installation – This unit has one of the simplest installation processes. You will only need an adjustable wrench and the components that come with the filter. There are several instructional tutorials you can watch if you encounter any problems.
  • Con:
    A Little Large – This water filter is a little larger than other models. This can be a problem if you also use a disposal system in a small cabinet.

Read More: CuZn UC-200

7. APEC WFS-1000 3 Stage Under Sink Water Filter

APEC WFS-1000 Super Capacity Premium Quality 3 Stage Under-Sink Water Filter SystemThis is one of the most popular under sink water filtration systems. It uses a 3-stage filtration process to remove most of the contaminants in the water, so you can rest assured that the water you’re drinking has a high quality.

One of the advantages of using this water filter is the ease of installation. Unlike other water filters that need several additional parts, this model comes with all the equipment you need for the installation. The filter also comes with pre-drilled holes so you can mount it on the wall.

Another advantage is the good water pressure it offers. Water filters usually do a great job at cleaning the water, but they don’t provide high water pressure. This is not the case. Despite passing the water through 3 separate filters, the water coming out of the faucet still has good pressure.

  • Pro:
    Good Faucet – This under sink water filter comes with a high-quality faucet. The faucet has a stainless steel construction, so it’s better than the cheap plastic models other filters come with.
  • Con:
    Faucet Has One Finish – The faucet only comes with a stainless steel finish. This might be a problem for people who have other finishes for their fixtures.

Read More: APEC WFS-1000

8. Frizzlife Under Sink Water Filter System

Frizzlife Under Sink Water Filter SystemIf you want to get rid of 99, 99% of water contaminants such as LEAD, Fluoride, Arsenic, Copper, VOCs, Cyst, and Chlorine, then you may consider getting this under sink water filter. You will probably be impressed by the fact that this filtration system is so precise that it can remove particles as small as 0, 5 microns. Another advantage of this product is that it not only filters the water but also makes sure that the useful minerals stay in it.

Installing this Frizzlife unit is very easy – you need to attach it directly to the water filtration system under your sink. You won’t need more than 3 minutes to mount this system, and you won’t have to pay a plumber to install it as you can do it yourself. Whenever you need to replace the filter, there is no even need to shut off the water supply. Unlike other similar products, this one doesn’t reduce the water flow.


  • This product is considered to be an eco-friendly option as you don’t throw away the whole plastic cartridge but just replace the filter.
  • You will find the installation of this filtration system an easy task.
  • The filter is compatible with both ½ inch and 3/8 inch water valves.

One of the most significant advantages of this product is that it leaves the water’s essential minerals

9. Doulton W9330958 SuperCarb Under Sink Water Filter

Doulton W9330958 SuperCarb Under Sink Filter SystemThis is an efficient under sink water filter capable of producing clean and crisp water. The Doulton Supercarb uses a cartridge filter to remove the contaminants in the water.

The cartridge filters the water in four different stages, making sure that most of the contaminants will be removed from your drinking water.

The first stage of the filtration consists of passing the water through a carbon block filter. This will remove most of the particles floating in the water, including bacteria, parasitic cysts, and any bad odors or tastes as well.

The second filter has antibacterial properties and it’s self-sterilizing so it won’t become contaminated over time. The third filter is another carbon one that removes chlorine, any lingering tastes and odors, and organic compounds. The fourth filter reduces the heavy metals present in your water.

  • Pro:
    Durable – This water filter has a solid housing and thick tubing. This makes the filter more durable than other products you’ll most likely find on the market.
  • Con:
    Needs Some Parts – Not all the parts needed for the installation are included in the box. You will have to buy some of them from your local store.

Read More: Doulton W9330958 SuperCarb

10. Woder 10K-GenII Ultra High Capacity Water Filter

Woder 10K-GenII Ultra High Capacity Direct Connect Water Filtration SystemThis is another budget choice we included on our list. The Woder under sink filtering system is very effective, despite its cheap price. This system is NSF approved, and all its components and filter materials are also approved.

One of the advantages of using this water filter is that it comes with all the pieces and accessories you need for the installation. This means you won’t need to use anything else than an adjustable wrench during this process.

Another advantage is the longevity of its filters. The Woder filters are capable of filtering up to 10,000 gallons of water, so you will be able to use them without changing the filters for roughly 3 years.

  • Pro:
    Long-Lasting Filters – Even though a filter change usually takes about 5 – 10 minutes, changing the filters once every 6 months can be tiresome and irritating. The filters used by this system can be changed only once every 3 years, resolving this problem.
  • Con:
    Slows Water Pressure – Using this filter will reduce the water pressure that reaches your faucet. The water filter will reduce the water pressure by up to 20%. This can be a problem if you have a low water pressure to start with.

11. Filtrete Advanced Under Sink Water Filtration System

Filtrete Advanced Undersink Water Filtration SystemThis is the cheapest model we included on our list and the only one in its price category good enough to make it. The Filtrete water filtering system might not cost much, but it’s very effective at removing contaminants nonetheless.

One of the advantages of using this filtration system is that it doesn’t come with a separate faucet for the filtered water. This system will connect directly to your cold water line, and all the water that passes through it will be filtered.

Installing this model is easy. Most people will have no problems installing the unit by themselves. The installation process shouldn’t take more than 30 minutes. The filters used by this system can filter up to 10,000 gallons of water. This means you will have to change them once this volume of water is filtered, or after 6 months have passed.

  • Pro:
    Good Filtration – This filtration system is very effective, despite its cheap price. It will remove up to 99.99% of the sediments, soils, sand, and cysts in your water, 96.6% of the odors and tastes, and more.
  • Con:
    Doesn’t Last 6 Months – Despite its advertising, this model won’t actually last 6 months, unless your water source is not very contaminated. When filtering a highly contaminated source, the filter will only last 4 months tops.

What is an Under-Sink Water Filter?

The name pretty much provides you with a definition of this device. However, we know that nothing is that simple, and we thought you could use a bit more in-depth explanation. An under-sink water filter takes water from the under-sink cold water pipe and sends it to the plastic tube where the filter stays. Then, once the water is pure enough, the device uses its faucet to deliver the water to the user.

This process happens on-demand, which means that no water goes to waste as is the case with a reverse osmosis system. An under-sink water filter takes care of the water that comes from the pipes under one sink exclusively. It does not filter your entire water supply. The filter faucet is also independent of your standard kitchen faucets for hot and cold water. You can still use those separately while benefiting from the clean filtered water for drinking and cooking.

Who Should Buy an Under-Sink Water Filter?

If you like, then you should get it! This mantra is the rule by which manufacturers live. Clients, however, want to know if something will serve them besides appealing to them. Everybody can benefit from cleaner water, but the under-sink water filter, in particular, will be suitable for some people more than it would be for others. One might need such a unit if:

  • You want to filter the water that comes solely from one sink and not the water that goes into your entire house.
  • You have limited space for installation, but still, want to remove the contaminants from your drinking water. The fact that you have a smaller house or flat should not stop you from pursuing the highest-quality water you can get for your family. An under-sink water filter will fit in a closed cabinet.
  • You want a budget-friendly unit, which requires low-cost maintenance. The replacement filters are cheap enough for you to be able to support the excellent condition of the device over time.
  • You don’t like calling plumbers and electricians to come to your house. The under-sink water filter is easy to install with basic plumbing skills. The manual will tell you everything you need to know along the way.
  • You are tired of accumulating water bottles. A water bottle might not be costly, but you would need to buy many of those over the week to drink enough water. You also cannot reuse a plastic bottle many times because of the smell and the unhealthy features of the plastic.
  • You want to enjoy the taste of the water. Many people do not drink the required amounts of water because they don’t like the taste of tap water. A filtering device will remove the odors and harmful particles to boost the flavor of fine minerals.

Buying Guide: How to Buy an Under Sink Water Filter

Most people want the same thing from an under-sink filter, and that is filtered water. However, there are some other things you should keep in mind when buying a filter, even if you don’t know it at the moment.

Features You Should Look For in an Under Sink Filter

  • Water Pressure

    When it comes to water filters, water pressure is very important. Only a few things can be more annoying than waiting a long time for a single glass of water to fill. Using a water filter capable of delivering good water pressure is especially important if you don’t have good water pressure, to begin with.

    Simple under sink water filters offer better water pressure than conventional ones. However, the downside of this increased pressure is that the water spends less time in the filter, so some of the contaminants might go through the filter without being blocked. This might actually be a problem if you have a highly contaminated water source. If the water is not overly contaminated, the number of contaminants that reach the faucet is insignificant.

  • Filtering Capacity

    Depending on the components of the filter cartridge, some filters will be more efficient at removing some categories of contaminants than others. Some models might have a very good overall filtering capacity, but still, lack the materials needed to remove a specific type of contaminant. This is why you should always use a home water quality testing kit before buying a filter. A kit will show you which contaminants have a higher level of your water source. Using this information, you should seek a model that’s very efficient at removing the particular compounds that contaminate your water.

  • Ease 0f Installation and Filter Change

    Another important thing you should take into consideration is the ease of installation, and how fast you can change the filters. You might be wondering why the installation matters since you only have to install the unit once. Well, the fact of the matter is that if a unit is difficult to install, you might damage it in the process. This can lead to a long and tiresome discussion with the customer service representative to send you a spare part, or another unit altogether.
    Another reason is that you shouldn’t spend money on hiring a plumber for the installation.

    This kind of filtering system is usually designed for DIY projects, so there’s no need to hire a professional. If you encounter any difficulty during the installation process, chances are you will find an instructional video online that might help. If you can’t install the unit even after watching the video tutorial, there is still one step you should take before hiring a professional. You should call customer service. Most often than not, customer service professionals can provide valuable information regarding the installation process.

    Using easy to change filters is also important. Most of the models we presented use filters that can be changed in under ten minutes. However, some other models on the market use filters that are really difficult to change. This can be a problem, even if you only have to change water filters once every 6 months or more.

  • Cartridge Longevity

    We’re certain that if you’ve been looking for under sink water filter systems, you already noticed that most of them need new filters every 6 months or so. However, there are some models that need a filter change only once every 3, or even 5 years. Is this really important?

    As a matter of fact, it is. Most cartridges work in the same way, so having a cartridge capable of filtering more water means that it’s better built. The cartridges that last longer are usually made with high-quality components, so they will also be very efficient at filtering the water.

    However, you should be aware that even though a cartridge might be advertised as lasting a certain period of time, it might not reach that period. The reason behind this is the water’s quality. When a cartridge is tested, it’s tested with municipal quality water.

    But, and this is a big but, municipal quality water as it exits the water treatment facility, not as you receive it through your faucet. The miles the water has to go through old pipes will contaminate it as well. This means that the water you use will most likely be more contaminated than the one the cartridge has been tested with, so it will last less than advertised.

Under-Sink Vs Countertop Water Filters

Under-sink and countertop water filtering systems are easy to compare since they both use activated carbon filters as their main component. Each of them has advantages and disadvantages so we created a list comparing the two.

  1. Under Sink Systems


    • Out of sight – They don’t interfere with your kitchen’s design
    • No countertop space – These are installed in the cabinet under your sink, so they won’t take up space on your countertops.
    • Good Filtration Rate – Unlike countertop filtering systems, these ones usually have a good filtration rate.


    • Larger – Even though they’re hidden under your sink, these filters can be larger than countertop ones. This means they will take up more storage space, even though not on the counters.
    • Harder To Install – These models are usually not difficult to install, but some countertop units don’t even need installation.
  2. Countertop Systems


    • Small – These units are small, so they won’t take up much storage space
    • Easier to install – These systems are easier to install than under-sink models.


    • Slower Filtration Rate – Countertop filters usually take longer to filter the same amount of water as the under-sink models.
    • Can Ruin Your Design – These filters don’t look good, so they might ruin your kitchen’s design.

Advantages and Disadvantages of Under-Sink Water Filters

Clean water to drink? Without the harmful elements? Sure, bring it over! But wait – is there anything else I should know?

This is the conversation people have in their heads when they find a new product that seems attractive but unfamiliar. It is fair that you have your doubts, and it is a good thing that you remain critical before making a final decision. As much as we love the qualities of the under-sink water filter, we think that you should be aware of all the advantages and disadvantages of this product.


We shall begin with the good news. Here are some of the under-sink water filter’s primary benefits:

Water Taste Improvements

This advantage is also the purpose of the unit. The under-sink water filter can make you want to drink more water because it improves the taste and eliminates unpleasant odors.

Water Quality Improvements

Since tap water contains a lot of contaminants, every house needs a filter to remove those. An under-sink water filter purifies the water in the most important location – your kitchen.


This feature is one side of the coin. The device filters the tap water and allows you to fill a reusable insulated water bottle before you leave your house. Thus, the amount of bottled water purchases decreases together with the consumption of plastic products.

No Big Storage Requirements

You will not even be able to see the under-sink water filter because it stays in a closed cabinet. Thus, you do not need to find a vast space as you would need to do for a whole house filtering system.


Even though it does not come naturally, installing an under-sink water filter requires minimum capabilities. You can learn those skills from a simple DIY video on the Internet, or by following the instructions provided by the manufacturer. Also, check out our blog post on DIY water filtration systems.

Reasonable Price

Like every filter, this device will have some additional expenses for maintenance. However, its purchase price is not high, and the replacement filters also come at a low cost.


There are options for each user, depending on the number of contaminants you would want to remove. You can choose a standard or a more advanced device to serve your needs.


A simple filter replacement is all that the machine would want from you.


The bad news may go in one ear and out the other, or they may stick with you. Our responsibility as your guides is to notify you of them and let you decide the weight of their importance. So here are the under-sink water filter’s drawbacks:

Single Outlet

The under-sink water filter cleans the water for only one faucet in your house. Unlike other systems, this device is designed to provide a single sink with purified water. To enjoy filtered water in different spots in your home, you will either need another filtering unit or a whole house water filter system. You can also go through our reviews on the best faucet water filters.

Separate Tap

This type of filtering device requires its own faucet to deliver clean water. You can install either a standard filter tap or a three-way tap that is connected to your hot and cold water plumbs as well.

Under Sink Water Filter Installation & Maintenance

  • Under Sink Water Filter Installation

    under sink water filter installationUnder-sink filtration systems are usually easy to install. Here is how you do it

    • Remove the tubing under your sink
    • Mark the location of the new filter
    • Make all the necessary plumbing connections
    • Connect the filter to the sink
    • Screw the filter in if you choose a mounting location
    • Test the new filter

    You should always follow the instructions manual the manufacturer provides. If you’re uncertain about how to continue the installation process, you should search for video tutorials or contact customer support.

  • When Should I Change My Water Filter Cartridge?

    There is no general answer to this question. Some systems will need a filter change once every 6 months, while others can filter water for up to 5 years without a single one.

    You should always follow the manufacturer’s instructions and clean and replace cartridges of your under sink water filter at the appropriate time. Some systems will automatically notify you when it’s time to change the filters.

  • How to Clean & Replace Cartridges In Your Under Sink Water Filter System

    This process will also vary according to the model, but there are some steps you should always take when changing the filters.

    • Turn off the water supply
    • Drain the water in the system by opening the faucet
    • Open the casing using a screwdriver or the tool the manufacturer provided
    • Remove the filters
    • Clean the casing
    • Replace the filter
    • Close the casing
    • Turn the water on and check for leaks

    You should always change all the filters at the same time, even though some might look better than others.

How Under Sink Water Filters Work

Now that you’re looking to buy an under sink water filter, you might want to know how one works, so you can understand the differences between builds and models.

The first thing you need to know is there are two types of under sink water filters. The first one is called a simple under sink filter, while the other is called a conventional under sink filter. In the following section, we explain how each of the works, and the pros and cons of choosing between the two types.


  1. Simple Under Sink Filter

    Even though this system is called simple, the way it works is actually pretty complex. The term “simple” comes from the way the system is installed, rather than the way it works.

    When you install the simple under sink water filter, all the cold water supply is diverted through the filter. This system doesn’t use a separate faucet to deliver the water; it’s delivered through your regular faucet instead. Because the filter is connected to the cold water line, it won’t filter the hot water.

    The advantage of using this system is the ease of use. Instead of having two separate cold water faucets, one for filtered and one for unfiltered water, you have a simple system. Thus the name.

    Simple Under Sink Filters Pros

    • Cheap
    • No additional faucet required
    • No modifications to the sink or countertop required
    • Easier to install with flexible connectors

    Simple Under Sink Filters Cons

    • More water is filtered, so you’ll have to change the filters more often
    • The water reaching the filter has a higher flow, so some contaminants will escape the filtration.
  2. Conventional Under Sink System

    As you can probably guess by now, this system is called conventional because the first under sink filtering systems were only designed this way.

    To install a conventional under sink filtration system, you will need to divert the water in the main cold water pipe to the system using a connection. The connection is usually a short plastic tube. After the water is filtered, it is sent to a separate faucet mounted on the sink. Only the water that reaches that faucet will be filtered. The cold and hot water reaching your regular faucet will be unfiltered. Find out here whether a hot water dispenser is the best option for you. The system is always under pressure, so it will be able to send the water through the filter and then to the faucet.

    The main disadvantage of using this type of faucet is that you have to either buy a sink with two faucet holes, or you have to drill a new hole in the sink or the countertop.

    Conventional Under Sink Filters Pros

    • Filters last longer because only part of the water is filtered
    • Water is better filtered because the reduced flow rate allows it to stay longer in the filter
    • Can be easily installed on every type of plumbing

    Conventional Under Sink Filters Cons

    • An additional faucet is required
    • Some sinks and countertops will have to be adjusted to install the new faucet
    • Reduced flow rate.

The Benefits of Under Sink Water Filters

Under Sink Water Filter ReviewsModern under sink water filters are now able to reduce contaminants previously removed only when using a reverse osmosis system. Old models would only use an activated carbon filter to block the contaminants, but modern models use cartridge filters that combine more technologies.

Despite the new technologies used by under sink systems for filtering the water, the activated carbon water filter is their most important component. When it comes to under sink water filter systems, the more carbon they use, the better.

Here is a list of how using an under sink water filter will benefit you:

  • Removes Bad Odors and Tastes – Most under sink water filters use at least one activated carbon filter. This type of filter is very good at removing the bad smells and tastes from the water.
  • Sediment Removal – Some of the components of the cartridge filter are specially designed to remove the sediment from the water. Some cartridges will use a pleated polypropylene or a spun polypropylene especially for this, but the activated carbon filter will also help.
  • No Chlorine – Thanks to the activated carbon filter, chlorine is also removed. Some models will use an initial carbon filter to trap most of the larger contaminants and chemicals from the water, and a second carbon filter to make sure chemicals like chlorine are removed.
  • No Heavy Metals – These metals are either blocked by a treated activated carbon filter, or a KDF carbon filter combination
  • Less Fluoride – The under sink filtering systems use a special Alumina filter to remove the fluoride from the water. This removal is usually not complete, so some fluoride will reach the faucet.
  • No Arsenic – Thanks to the Alumina filter, the arsenic is also removed from the water.
  • Nitrite/Nitrate Reduction – Nitrates and nitrites are very dangerous for children and the elderly. The under-sink filters use an Anion resin cartridge to remove these compounds from the water.
  • Less Limescale – The cation resin in the filter’s cartridge will remove most of the calcium and magnesium in the water. This will lower the amount of limescale buildup on your sink.
  • Bacterial And Microorganism Removal – The cartridge used by the under sink water filters can also block bacteria from reaching the faucet. This is also true for other microorganisms like Cryptosporidium and Giardia.

Wrap Up

Now that you read our under sink water filter reviews and our comprehensive buying guide, we’re certain you’ll be able to choose the right model for your household.

As you could see in the article, the best under sink water filters are capable of blocking most contaminants from entering your drinking water.

It doesn’t matter if you get your water from a well, or if you get it from the municipal source, a good under sink filter will remove most of the contaminants that would otherwise reach your faucet.

You don’t really know how under sink filters work? That’s not a problem. You only have to read our short buying guide and you will understand how they filter the water. Understanding how they work will help you with making the right decision about which model to buy.

If you feel you didn’t find the right model in our under sink water filter reviews, you can see the other filtering solutions by clicking here.

Read more reviews on the highest-quality refrigerator water filters on our website.

2 thoughts on “11 Best Under Sink Water Filters – (Reviews & Guide 2021)”

  1. I really appreciate the buying guide you put together for home water filters. It is great advice to test your water before buying to determine the level of contaminants you would need filtered out. The area I live in is not known for having great tap water, and we also have old pipes in our house, so I bet there are a lot of contaminants. That’s why I’m looking into getting a filter.

  2. this article was so helpful and consolidated all the research i have been trying to do across multiple websites. thank you!


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