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Best Under Sink Water Filters of 2020

best under sink water filter reviews

Table of Contents

The best under sink water filter is designed for the removal of an array of contaminants from the water, including:

  • Chlorine and chloramines, taste and odor – using an activated carbon filter
  • Lead and heavy metals – using an activated carbon filter with an additional metal removal resin
  • Arsenic and fluoride – using an activated alumina cartridge with an additional iron oxide resin
  • Hardness minerals, including calcium and magnesium – using a cation resin cartridge
  • Large particles of sediment, like dirt, dust and rust – using a polypropylene filter
  • Bacteria and cysts – using a sediment filter or ceramic cartridge

Under counter filters may also remineralize water, reducing acidity and improving taste, with an additional remineralization filter.

Best under sink water filters

  • Waterdrop 3-Stage Ultra Filtration Under Sink Water Filter System
  • Aquasana 3-Stage Water Filter System
  • Filtrete Under Sink Water Filtration System
  • Woder WD-S-8K-DC
  • CuZn UC-200
  • APEC WFS-1000
  • Frizzlife Under Sink Water Filter System
  • iSpring US31
  • Clearly Filtered Under Sink Filtration System
Waterdrop 3-Stage Ultra Filtration Under Sink Water Filter System
Waterdrop 3-Stage Ultra Filtration Under Sink Water Filter System
Filter stages: 3
Dedicated faucet
Filter longevity: 24 months
Dimensions: 14.81 x 4.68 x 13.97 inches

Get 5% off with code WFG-5OFF

Aquasana 3-Stage Water Filter System
Aquasana 3-Stage Water Filter System review
Filter stages: 3
Dedicated faucet
Filter longevity: 6 months or 600 gallons
Dimensions: 12 x 4.2 x 9 inches

Filtrete Under Sink Water Filtration System
Filtrete Under Sink Water Filtration System review
Filter stages: 1
Filter longevity: 6 months
Dimensions: 4 x 6.8 x 14 inches

Woder WD-S-8K-DC
Woder WD-S-8K-DC review
Filter stages: 1
Filter longevity: 3 years or 8480 gallons
Dimensions: 3 x 3 x 15 inches

CuZn UC-200
CuZn UC-200 review
Filter stages: 1
Filter longevity: 5 years or 50,000 gallons
Dimensions: 4.5 x 4.5 x 15 inches

APEC WFS-1000 review
Filter stages: 3
Dedicated faucet
Filter longevity: > 12 months
Dimensions: 6 x 15 x 12 inches

Frizzlife Under Sink Water Filter System
Frizzlife Under Sink Water Filter System review
Filter stages: 2
Filter longevity: 2 years or 1600 gallons
Dimensions: 13.9 x 5.6 x 5.4 inches

iSpring US31
iSpring US31 review
Filter stages: 3
Dedicated faucet
Filter longevity: 6 or 12 months
Dimensions: 16 x 6 x 16 inches

Clearly Filtered Under Sink Filtration System
Clearly Filtered Under Sink Filtration System review
Filter stages: 3
Filter longevity: 1 year
Dimensions: 19.7 x 15.7 x 3.7 inches

Under Counter Water Filter Reviews 2020

Waterdrop 3-Stage Ultra Filtration Under Sink Water Filter System

Waterdrop 3-Stage Ultra Filtration Under Sink Water Filter System

Get 5% off with code WFG-5OFF

The Waterdrop under sink ultra filtration system removes 99% of all contaminants larger than 0.01 μm as well as bacteria and other microorganisms. This is accomplished with the system’s 3-stage filtration process:

  1. PP filter – Removes large particles and other impurities
  2. UF filter – Removes 100’s of common contaminants
  3. CT filter – Removes chlorine, heavy metals including lead, and improves taste

The system utilizes an innovative integrated waterway which allows you to change the filters without turning off the water supply to the unit. This also prevents leakage and water loss.

Speaking of changing the filters, the UF membranes used in this system are extremely long lasting; up to 24 months! When it’s time to change the filters, the smart indication lights on the front of the unit will let you know by changing colors.

Waterdrop designed this unit with DIY installation in mind. You can instal this system in a matter of minutes yourself. Quick and easy. It comes with its own separate faucet as an added perk.


  • Innovative horizontal design saves space
  • Lights indicate when it’s time to change filters
  • Filters last longer than most other under sink systems


  • Higher price point
  • 3 filters to replace

Aquasana 3-Stage Water Filter System

Aquasana 3-Stage Water Filter System review

The Aquasana kitchen sink filter is manufactured by Aquasana, one of the most popular water filter brands in the US. The unit is tested and certified to NSF Standards 42, 53, 401 and P474, meaning it has been industry backed to reduce or remove chlorine, lead, VOCs, giardia, pesticides and herbicides, prescription drugs, detergents, PFOA and PFOS.

The system can remove up to 99% of more than 70 contaminants, but it won’t remove TDS (you’ll need a reverse osmosis system for that). It has a high flow rate, at around half a gallon of water per minute, so you can get immediate access to clean water from your faucet.

You will need to change the filters every 6 months, which isn’t the best lifespan we have seen for an under sink filter. However, the filters are really easy to change, with no need to disconnect the unit from the water line – you just remove the old ones and snap the new ones in place.

Included with the Aquasana under counter filter is everything you need for installation, plus the first set of filters. Even if you don’t have much DIY knowledge, you won’t need to call a plumber to do the job for you.


  • NSF certified for removal of 77 contaminants
  • Easy-change filters
  • Installation doesn’t need an expert


  • Filters only last for 6 months
  • No replacement o-rings if unit starts to leak

Filtrete Under Sink Water Filtration System

Filtrete Under Sink Water Filtration System review

The Filtrete under counter filter is NSF 42 and 53 certified for the removal of aesthetic impurities and health-related contaminants. This gives assurance that this unit can remove or greatly reduce the likes of chlorine, VOCs, microbial cysts, and lead.

Without the need to connect the Filtrete to a dedicated or standard faucet, you can install it anywhere you wish, including to any kitchen or bath faucet. The installation process takes roughly 30 minutes, and thanks to the system’s simple push-fitting connections, you don’t need to be an expert for the job.

The filters in the Filtrete have a maximum capacity of 2,000 gallons, giving them a lifespan of approximately 6 months. You won’t experience an issue with water flow when using this filter, which filters water at a rate of 2.25 GPM. This is actually higher than the average GPM of a faucet, which is about 1 to 1.5 GPM. You can buy replacement filters online.

For installation, the manufacturers have produced a video on what to do, and written instructions are also available with the unit and online. You just need to attach the water supply hose to the filter head’s input and output connections and screw the filter in place.


  • Quick-connect fittings make installation easier
  • Makes water look and taste better
  • Easy to use


  • Flow rate will decrease over time
  • Filters may not last 6 months for some homes

Woder WD-S-8K-DC

Woder WD-S-8K-DC review

The Woder WD-S-8K-DC is a WQA certified under sink water filter that can remove contaminants that give water a bad taste and odor, like chlorine, as well as heavy metals, lead and chromium. It has a 2 GPM flow rate, which is fairly good for an under sink filter.

The clear selling point of this filter is that it has an ultra-high capacity, lasting up to 3 years, or approximately 8,480 gallons. It lasts longest when you use it with water that has been municipally treated, and not well water.

You don’t need any plumbing skills or experience to install the Woder WD-S-8K-DC. It uses direct connect hoses that you can simply attach onto any US water valve under the sink of your choice (bathroom sinks included).

The filters themselves have a unique technology that allows them to filter 99.9% of lead and chlorine, plus greatly reduce other contaminants, without removing healthy minerals from water. If you’re interested in high filtration but don’t want to lose out on certain minerals, a filter like this Woder system will work better for you than alternative reverse osmosis systems.


  • Filters last for up to 3 years
  • Very effective contaminant removal
  • Leaves healthy minerals in water


  • Doesn’t work with well water
  • Reduces flow rate over time

CuZn UC-200

CuZn UC-200 review

The CuZn UC-200 is a high capacity under counter filter that has an incredible capacity of up to 5 years per filter. Designed to purify municipal water (not well water), this filter connects directly up to the cold water line underneath the kitchen sink. Installation takes a matter of minutes, and the only tool you need is an adjustable wrench to tighten the connections.

With a three-stage filtration process, the CuZn UC-200 can remove chlorine, heavy metals, sediment, herbicides, pesticides, algae and bacteria. It uses KDF and coconut shell carbon filters that purify water without removing beneficial minerals like calcium. Keep in mind that a TDS reader isn’t an effective way of testing water quality after using the CuZn, as it doesn’t remove all TDS like reverse osmosis systems do.

The CuZn under sink water purifier uses a unique bacteriostatic filtration system, not a carbon-only system. This type of system is less susceptible to bacteria or mold growth, It doesn’t soften water or remove hard water minerals – you will need to buy a reverse osmosis unit or a water softener for that job. Instead, it improves water taste and flavor, and makes it healthier for drinking.


  • Great filter capacity at up to 5 years
  • Removes contaminants while leaving behind healthy minerals
  • Simple installation


  • Unit may be too large for some under sink areas
  • Included instructions for installation are minimal


APEC WFS-1000 review

The APEC WFS-1000 uses NSF certified parts and filters and can reduce or eliminate a variety of contaminants in water. The unit is designed and manufactured in the US, and removes chemicals like chlorine, which add unpleasant taste and odor to water.

There are 3 filters in the WFS-1000 – 2 carbon block filters, which remove chemicals, taste and odors, and 1 sediment filter, which removes dust, rust and other particles. The unit comes with a lead-free faucet which you can choose to install if you don’t want to risk leaching after filtration, but this is optional for use.

Each filter in the APEC WFS-1000 is designed to last for 12 months – which is impressive, though some filters from similar products on the market claim to last for 3 or even 5 years. You can buy replacement filters online; they cost between $50 and $100 for multipacks of 2 or 3.

There is no tank needed for this filter, and water travels straight through the filter and out of the faucet, with no waiting around on your part. All of the water that flows through the system ends up in your cup, no rinsing or flushing needed, helping you to save money and water.


  • Comes with optional lead free faucet
  • Uses NSF certified parts
  • No flushing or rinsing needed


  • Unit itself isn’t NSF certified
  • Doesn’t remove TDS

Frizzlife Under Sink Water Filter System

Frizzlife Under Sink Water Filter System review

The Frizzlife is an under counter water filter that removes up to 99.9% of chlorine taste and odor, and lead. The unit has been tested by IAMPO R&T, an independent third-party research and testing company, against NSF 42 and 53, for the reduction of aesthetic impurities and health-related contaminants. It’s unclear from the Frizzlife’s marketing materials whether it is NSF certified for these Standards or not.

The unit uses 1 filter cartridge that functions as 2 cartridges combined. There are 2 stages of filtration – the first using a 0.5 micron sediment filter media to remove particles like sand, rust and silt; and the second using a 0.5 micron carbon block filter media to reduce heavy metals, chlorine, VOCs and other particles.

Installation is straightforward, thanks to the Frizzlife’s highly compatible fittings, and the only maintenance you’ll need to do is changing the filter after around 12 months. The filter features an auto shut-off switch, so you don’t need to shut off your whole water supply while carrying out this maintenance. There is a video online to help you with the filter process, which takes roughly 3 minutes to carry out.


  • NSF tested
  • Straightforward installation
  • Space-saving 2 in 1 filter


  • Hose connectors not compatible with all water lines
  • Some users noticed a drop in water pressure

iSpring US31

iSpring US31 review

The iSpring US31 has been independently third party tested for NSF Standards 42, 53 and 61, for reduction of chlorine, lead, VOCs, bacteria and more. It also certifies that the components in the iSpring address human health effects and won’t cause leaching.

There are multiple stages of filtration in the iSpring US31: a PP (polypropylene) sediment filter, a dual CTO (chlorine taste and odor) carbon filter, and a unique GAC (granular activated carbon) filter. Combined, these filters can remove chemicals, bad odor and taste, and larger particles and sediment from water.

With a flow rate of up to 1GPM, this iSpring system may produce water more slowly than other under counter water filters, but you still won’t have to wait more than a minute to fill your glass. With no tank needed, the unit doesn’t take up much under sink space, making it possible for use in small kitchens and bathrooms.

The unit comes with its own brushed nickel faucet, which you can use if you choose. Filters need changing every 6 to 12 months, judging by flow rate and taste. Helpfully, the first-stage sediment filter has clear housing, making it much easier to inspect the filter and determine when it’s looking visibly dirty.


  • NSF tested and certified
  • Clear filter housing for filter inspection
  • Comes with its own faucet


  • Not the fastest advertised flow rate
  • Some customers have experienced leaking between connections

Clearly Filtered Under Sink Filtration System

Clearly Filtered Under Sink Filtration System review

The Clearly Filtered under sink filtration system has 3 separate filtration stages for the removal of lead, fluoride, PFOA, pesticides, and pharmaceuticals, while retaining healthy minerals like magnesium and calcium. The unit has been independently tested to NSF and EPA Standards, 42, 53, 244, 401 and 473. This means that while it doesn’t have an NSF certification, it has been third-party tested to meet these Standards.

Each filter lasts between 9 and 15 months, depending on how many people are in your household. You can buy replacement filters directly from Clearly Filtered online, and changing the filters is a simple case of unclicking the old ones and clicking the new ones in place.

Installation of the Clearly Filtered under sink system takes, according to the manufacturer, just 2 minutes. If you’re not a skilled plumber, you should factor in time for reading instructions and doubling back on yourself to check you’re right – it’s more likely to take 10 minutes, which is still great. You just need to connect each end of the unit up to your cold water line, and you won’t need to call a plumber for the job.

You can use the water produced by the Clearly Filtered unit in a number of different ways. You can drink it, make baby formula with it, wash vegetables in it, and water your plants with it. As the filter removes more than 200 contaminants from water, you should notice a distinct improvement in taste, color and odor.


  • Filters last for up to 15 months
  • Easy to install
  • NSF third-party tested


  • Upfront cost is quite high & filter replacement expensive
  • Some customers noticed a reduction in water pressure

Under Sink Water Filter Buyer’s Guide

We know how difficult it can be deciding whether or not you need to install an under counter water filter in your home or not. As well as going through the various products available to find the one that best fits your unique needs.

That’s why we created the following buyer’s guide to help you make the most informed decision possible.

What is an Kitchen Sink Water Filter?

An under counter water filter is a point-of-use water filtration system that’s mounted underneath a kitchen sink, designed to filter water directly at the source.

These filters are designed to produce water on demand. This means that they don’t require a storage tank, as they get to work as soon as you turn on your faucet, and produce water to come straight out for drinking.

Note that an under sink filter is not the same concept as a reverse osmosis filter, which is also commonly installed in an under sink area. Unlike reverse osmosis systems, an under sink filter is designed to filter water directly while producing no wastewater in the process.

All water that enters an under sink system comes out as usable drinking water.

The filter is connected to an under sink cold water pipe. Water travels from this pipe into the pressurized filter, where water is cleaned and sent back up through a pipe to the faucet.

A special faucet may be be supplied for producing filtered water independently of the hot and cold faucet in a kitchen sink area. However, it’s becoming more common now for modern under sink faucets to divert the entire sink’s cold water supply to the filter before it reaches the faucet.

This means that no separate faucet is required, and all cold water from the faucet is filtered, while the hot water remains unchanged.

Why use an under counter water filter?

Improves water taste

While many people won’t purchase an kitchen sink filter specifically to improve the taste of their water, it’s an added benefit that shouldn’t go ignored.

Removing impurities and contaminants that can give the water a bad taste or odor, like chlorine and sulfur – guilty for giving water that rotten egg smell – will not only make your water safer to drink, but better to taste.

Removes contaminants and impurities

Depending on the area you live in, your water could contain all sorts of harmful contaminants and impurities, including bacteria and viruses, chlorine, pesticides and herbicides, lead and heavy metals, and larger particles like dirt and rust.

These impurities aren’t always 100% filtered out by your local water treatment plant, and while they won’t make you sick if you drink them, they’re not the best for your health.

The only way to ensure all of the nasty stuff is removed from your drinking water is to run it through the best under sink water filter.

The separate filters in your system will be able to effectively remove a wide range of different contaminants, making water fresher, cleaner and safer to drink.


If you’ve been buying bottled water for as long as you can remember, an under counter water filter will put an end to your water-spending spree.

You’ll be able to enjoy the taste of your own tap water in the knowledge that you’re no longer drinking harmful contaminants or impurities.

The cost of replacing your filters from time to time will be far lower than the cost of buying multi-packs of water bottles from the store every week.

Undersink filters are also generally less expensive than other water filtration systems to purchase, last for many years, and tend to be more efficient.

The initial price you pay for your undersink system will soon be compensated by its benefits, making it a cost-efficient purchase.

Space saving

If you don’t have the counter space for a countertop water filter, or you just don’t want something clunky taking up your empty surfaces, an under counter water filter is a space-saving alternative.

While it will still require you make some room for it in your under sink cupboard, you won’t need to have it out on display for it to do its job properly.

water filter for sink

Tailored to suit you

While some under counter water filtration systems might come with a particular set of filters, you’ll generally be able to choose to add on as many or as few filters to suit your water filtration requirements.

For instance, if you’re particularly keen to remove chlorine from your system, you can add an activated carbon filter.

For removing bacteria, you can purchase a ceramic cartridge.

If you want to improve the alkalinity of water, you can add a remineralization filter to your system.

This allows you to produce drinking water to your specific tastes.

Simple to install and maintain

Because under sink filters don’t use a storage tank, and most don’t need a separate faucet, they’re very simple to install. You won’t need plumbing experience to get the job done. The filters themselves require very little assembly, if any, and from there, it’s just a case of connecting the main body of the filter unit up to the cold water pipe using flexible connectors.

Filters will need changing from time to time, assuming that you use them frequently.

When you buy your filters initially, you’ll be given a maintenance sheet explaining how frequently your filters require changing. Stick to this sheet and change your filters when necessary, and your under sink system will continue to run healthily for years.

Who should buy an under sink water filter?

You might be wondering whether an under counter filter is for you. Technically, anyone can take advantage of this type of filter, but you might be particularly interested if your incoming water is particularly hard.

You might also be interested in an under counter filtration system if you want to drink contaminant-free water. All drinking water is treated with chemicals like chlorine for disinfectant purposes, and while this isn’t unsafe for drink, it’s not ideal for putting into your body even in small amounts.

Even if you don’t particularly mind the taste of your water, you might want to purchase an under counter filter for water softening purposes.

Finally, if your water contains an impurity, like rust or sulfur, that causes it to take on an unpleasant appearance, odor or taste, an under sink filter might be a good solution for you. Sulfur can give water a distinctive rotten egg smell, while rust can give water a metallic taste and a slight brownish tinge.

Ultimately, under counter water filters are for anyone who wants to produce clear, clean water that’s free of impurities and contaminants. No matter where in the country you live, you’ll be able to improve your water quality, taste and functionality with a drinking water filtration system.

How under sink filters work

Once you’ve installed your system, it will get to work producing filtered drinking water immediately. The exact way your system works depends on which type of filter you go for: a simple system or a conventional unit. Unlike what you’d expect, a simple filter is actually a little more complex in its performance.

Here’s how it works:

  1. When you turn on your faucet, water from your cold water supply is diverted into the filter which is usually connected to your cold water pipe with a flexible plastic tube.
  2. Water then passes through the unit, where each separate filter removes contaminants and impurities, as well as hardness-causing minerals.
  3. Filtered water is not stored in a tank, but flows straight to your faucet.
  4. Note that in the case of a simple under counter water filter, you won’t need to install another faucet for water delivery. Water will pass through your standard faucet, which will deliver unfiltered hot water, but will only ever deliver filtered cold water.

A conventional water filter works a little differently and requires a more detailed installation. If you know someone who’s owned an under sink filter for several years now, it’s likely that they have a conventional system, as this is the model that was first introduced.

Here’s how a conventional water filter works:

  1. When you turn on your faucet, water is diverted from your main cold water pipe in the same way as mentioned for a simple water system – through a flexible plastic tube.
  2. The water passes through the filters inside the conventional system, which remove hard minerals, other impurities and contaminants, cleaning the water.
  3. Once water has been filtered, it flows straight to the faucet through another flexible plastic tube.
  4. In this instance, the faucet is separate from a standard sink faucet. This means that if you were to turn on your standard faucet, you’d get hot and cold unfiltered water, but if you turned on your separate faucet, you’d get filtered cold water only.
under sink water filter reviews

How to Buy an Under Counter Water Filter

You can buy most under-sink water filters online or from home improvement stores. Nowadays, most people shop online, because there’s more of a selection to choose from, and there’s less pressure to make a purchase.

Buying an under counter filter is not a process to be rushed into. You’ll want to consider exactly what you want to get out of a filter, as well as practicalities, like cost, upkeep and storage space.

You should take a look at all the reviews that are available for a product, and compare costs, features and the product manufacturers themselves.

When it comes to making a purchase, don’t hesitate to reach out to the manufacturer directly if you have a question that isn’t answered in the product description or FAQs.

Considerations before buying an under sink filter

Before you jump into a purchase, there are a number of things you should consider that will help you get the most out of your system. Have a think about the following features while you’re deciding which product is for you:

Filter Type

The type of system you purchase will determine the ease of installation. Simple kitchen sink filters require easier installation, as they don’t require a separate faucet to be fitted at your kitchen sink.

Conventional water filters divert water over to a different faucet, which is usually included in the package. It might be that you’d rather purchase a simple under-sink water filter based on installation specifics alone, but conventional systems have their uses. If you want the option of having both hard and soft cold drinking water, having two separate faucets will give you this choice.


Your under sink measurements need to be compared to your systems’ measurements to make sure the unit will fit comfortably in a given space.

Some under sink water filters take up a lot more room than others, and if you don’t have much room to give up, you might want to consider a more compact system with smaller filters that perform a number of tasks in one.

Another reason to consider space is that you might want to expand on your filtration system in the future. While a standard under counter water filter generally comes with stages for softening the water, removing sediments, and eliminating chemicals like chlorine and contaminants like lead, you might want to purchase additional filters to connect up to your system, such as remineralization stage. You’ll need to factor in extra storage space for these filters if you can see yourself adding on in the future.

under counter water filter

Ease of installation

All water systems vary in their installation process. The majority of under sink filters will come partially assembled, and you’ll only need to connect the system to your cold water pipe at the right locations. You won’t need a plumber for most under sink filter installations, but it’s worth reading up on installation for your particular model to be sure on exactly how the installation process will work.

Keep in mind that if you’re looking to purchase a conventional water system, installation will be more complex because you’ll be required to fit a faucet at your sink specifically for the filtered water to run through. This can still be carried out at-home without the need for a plumber’s assistance, although some people may feel more comfortable hiring an expert to do the job.

Installation & maintenance costs

If you are choosing to hire a handyman to install your kitchen sink water, you’ll need to factor in the costs of doing so.

All products should come with detailed instructions for installation, so it’s worth giving the task a go yourself first before paying for extra help you might not need.

In terms of maintenance, most kitchen sink water filtering systems only require that you change their filters when they’re no longer performing as efficiently.

You should be able to find more information about filter changing in your system’s handbook, and generally, this is a job you can do yourself. New filters will cost additional money, but are essential for maintaining your system long into the future.

When you’re purchasing an under-sink filter, make sure replacement filters are widely available and at a relatively low cost. Most will require changing after around 6 months to 2 years, depending on level of use.


There are two main certifications that a manufacturer of an under counter water filter can obtain: NSF certification and Water Quality Association (WQA) certification. Both of these tell a customer that a product has been third-party tested and performs as efficiently as the manufacturer claims it does.

NSF certification

NSF International is an American product testing, inspection and certification organization. NSF certification proves that a product complies to the regulatory and purchasing specifications set out by the organisation.

The process of obtaining an NSF International certification varies from product to product, but generally, a manufacturer will be required to submit product details and information, before agreeing for their product to undergo lab testing and evaluation. The manufacturer should also allow NSF International to inspect their manufacturing facility and sample the product in a practical situation. When the contract for certification is signed, businesses must agree to annual plant inspections and retesting.

Water Quality Association (WQA)

Like NSF International, the Water Quality Association is a third-party independent organization that represents the residential, commercial, and industrial segments of the industry.

Manufacturers looking to prove that their product meets the expected water filtration standards can apply to obtain WQA certification.

Being WQA certified demonstrates a manufacturer’s commitment to high professional standards and improved customer service. To apply for certification, a manufacturer must offer relevant product information to the WQA, fill out an application agreement, and submit the product for extensive performance testing to ensure it complies to the certification standards.

Features to Look For

Filter Longevity

To get the best use out of your under-sink water filter, look for a system with high-quality filters with long lifespans. All filters inevitably require changing after so many months, but the longer between filter replacement, the better value for money they’ll be.

It’s not always easy to know when a manufacturer’s claims about filter lifespans are true, so make sure to read up on customer reviews and FAQs to see what the community has to say about the product.

Lead-free Faucet

If you’re purchasing a conventional under counter water filter, you’ll require a faucet for the filtered water to flow from.

Most systems will come with a faucet included in the initial price, and the more durable and good quality it is, the better. Lead-free faucets are always best, as they prevent clean water from picking up additional contaminants on its way from the filter. Again, check customer reviews and FAQs to get an idea about the quality of a faucet. The manufacturer may also give you the option to choose between a number of faucet designs, to help you find the one that most suits your kitchen space.

kitchen sink water filter

High-Quality Components

From the connecting tubes and the filter bodies, to the faucet and the filters themselves, you should be looking for a system with the highest quality components.

Not only will good-quality features help your system to filter water the most efficiently and effectively, they’ll last longer and reduce the need for maintenance and upkeep.

Look at customer reviews to learn what customers think about a system’s components on a whole. If you notice a trend in complaints about cracked or broken parts, it might be worth avoiding the system and looking elsewhere.

Thorough Instructions

One of the biggest perks of an under sink water filter is that you can install it yourself, without the need for a plumber or a handyman.

While some people may find installation fairly straightforward without instructions, those of us who are less mechanically skilled will appreciate thorough installation and maintenance guidance in both written and video form.

Generally, installation instructions are clear and in-depth for most under-sink water filter products, and you’ll be able to find online videos helping you to perform more general tasks like installing a faucet and changing a filter.

Most manufacturers also offer live support for customers. If you’re unsure about the support you’ll get from a manufacturer of a filter you’re considering, contact them prior to purchase.

Under Sink Vs Countertop Water Filters

One of the biggest questions you might be asking yourself prior to purchasing a water filter is: “Should I buy an under sink or countertop water filter?”

There’s no yes or no either way to this question, but it’s worth thoroughly comparing both filter options to help you make a choice that best suits your requirements.

Here’s what you need to know about under-sink vs countertop water filter systems:

Size & Appearance

Countertop water filters tend to be smaller and more compact in size, owing to the fact that they take up counter space. They may also look more visually appealing in design than under-sink water filters, which are stored out of sight, making filter appearance less important.


Under counter water filters are stored away in your under-sink cupboard or storage area, which means it’s not always in sight. Countertop water filters take up side space and can’t be stored away when they’re in use.

Most countertop water filters will need attaching to your kitchen sink faucet via a plastic tube, which doesn’t look so appealing on display.

Filtered output

Most under sink and countertop water filters are considered point-of-use systems and don’t have water storage tanks, so output should be similar for both.

You won’t have to wait long at all for filtered water to be produced, providing you purchase a system with good-quality components.


You should expect to pay a little more for an under-sink water filter than a countertop alternative. This is usually due to filter quality, performance speed and unit size.


Under counter water filters require a more in-depth installation, while most countertop water filters simply require switching on – and then they’re ready to go. You might need to call a plumber to help you install your under-sink water filter if you’re uncomfortable carrying out the task yourself.

Under Sink Filter Installation and Maintenance

Most under sink water filtering systems are simple to install and maintain. You won’t need to hire a plumber unless you’re particularly hesitant to give installation a go yourself.

Depending on the model you purchase, your water filter might have its own unique installation requirements, but the basic installation processes tend to be fairly similar across all models.

If you’re looking for more information regarding installation before you make a purchase, or you just want to know how it’s done, here’s a step-by-step of the process:

Installation step by step

  1. Turn off your water supply – Before you get going with installation, you’ll need to turn off your cold water supply to stop water flow through the cold water pipe leading to your sink. This is to allow you to connect your filter without causing a leak. Lift your kitchen sink faucet to relieve any build-up of pressure from inside the pipe.
  2. Assemble your filter system – Your filter system should come partially assembled, so all you’ll need to do is clear out your cupboard space and set the filters in place if they’re not already, and set the system up in the under-sink location you’re planning to store it in.
  3. Connect the filter system to the cold water pipe – Undo the cold water supply line and connect one of the flexible tubes to the pipe using the two-piece fittings provided. Connect the other side of the plastic tubing to your pressure limiting valve, then feed the pressure limiting valve into the inlet of your water filter system, connecting in place.
  4. OPTIONAL – Install the faucet – If you’re installing a conventional water filter system, mark an appropriate area of your sink for fitting the faucet, then drill a 13 millimetre hole. Run the water line through the faucet using the plastic tubing and plug its other end into the filter (Note: ignore this step if you’re installing a simple water filtration system).
  5. Connect tubing to cold water pipe – If you’re not using a separate faucet for your water filtration system, you’ll just need to connect the other end of your filter up to the main cold water pipe again, at a slightly higher spot, but using the same technique as mentioned above. The filter will be marked to show which end will send clean water out, and which will receive tap water in, so make sure you’ve got them the right way around.
  6. Secure your water filter to the wall – Securing your water filter in place is optional, but makes for a neater appearance and helps to save space. You’ll be able to unscrew your filters from the wall holder whenever they need changing.
  7. Turn the cold water back on – Once your filter is fitted, it’s time to turn your cold water back on and check for leaks. If any leaks are detected, turn the water off, switch on your valve to relieve pressure, and tighten your fixings.
  8. Run water through your under-sink filter – Turn on your faucet and let water flow for a couple of minutes to flush out your under-sink water filter ready for use. You’ll then be able to drink water produced by the filter immediately.
under sink water filter installation

When to change the filter

You’ll need to look specifically at the user manual of your water filter to be sure when exactly filters will need changing, but generally, you can expect them to last between 6 months and 2 years before you’ll have to purchase a filter replacement.

You may need to change your filters more frequently if:

  • Your ingoing water is particularly hard, or contains a high level of total dissolved solids
  • You use your faucet more frequently than the average home or business owner

While manufacturers can offer guidance for filter changing, you might want to purchase a drinking water test kit that you can use on a monthly basis to check that your filters are still working efficiently. You can buy these kits online at a relatively low cost.

How to clean and replace filters

The simplest way to ensure your under-sink water filter lasts longer and works efficiently is to clean the system and replace the filters as advised.

You’ll find more specific information about cleaning and sanitation in your filter’s user manual, but generally, you’ll need to take the system apart and sanitize the components separately.

The housing for all filter units can be washed in warm, soapy water to remove any build-up of sediment. Note that you won’t need to wash or clean the filters themselves as you’ll simply replace them when they’re no longer doing a good job.

When it’s time to change your filters, most under counter water filtration systems will have a simple set-up that allows you to click or twist the filters out of place. New filters can be twisted or clicked back in, and once the system has been flushed with water for a minute or two, they’ll be ready to go.

Some filtration systems come with filter wrenches for screwing and unscrewing the filters in place. Make sure you use these wrenches, particularly when tightening your filters, to ensure the system works correctly and there are no leaks.

Disadvantages of Under Sink Systems

As with all types of water filtration products, there are a number of advantages to an under-sink filter, including:

Single Point of Use

If you choose to install your under counter water filter at your kitchen sink, as most people do, your filter will produce clean, pure drinking water that will run either out of your standard faucet or, in the case of a conventional filter, the separate faucet that came with the system.

While for some people, clean drinking water at the kitchen sink is enough, others might want to extend the benefits of contaminant-free water to the entire household.

Because under sink filters are designed for under-sink use only, you wouldn’t be able to connect your system to appliances like your washing machine, for instance, if you wanted the soft water benefits for your laundry.

You also wouldn’t usually be able to connect your system to a bathroom sink, especially if you purchased a conventional system with a kitchen-style faucet. You can, however, connect your under-sink filters to ice machines, refrigerators or coffee makers if you want to.

You might also be interested in: Whole house water filters

Installation Challenges

Most people with basic handy skills should be fine to install an under-sink water filtration system, but you might simply feel more comfortable passing the job on to an expert.

This would mean factoring in an additional cost on top of your initial price for the filter.

Whether you hire a plumber for help or not, installation is fairly inconvenient, especially if you’re installing a conventional system with a faucet. Certain aspects of installation may prove quite tedious, although there are plenty of online videos that simplify the process somewhat.

Water Pressure

Every home and business has its own ingoing water supply, and, depending on the region you live in, your water pressure may be significantly higher or lower than the average.

For under-sink water filters, a water pressure of between 40 to 70 PSI is generally recommended for optimal filter efficiency.

You can test your ingoing water pressure using a PSI pressure gauge. The optimal water pressure for an under counter water filter is 60 PSI, and anything that falls below this may not filter as effectively.

Users with a water pressure of 30 PSI or below should purchase a booster pump to speed up water flow into the filter.

Upfront Cost

Although an under counter filter is, in all, great value for money, the initial cost of the filter itself might be off-putting for some.

Most under sink water filters cost between $200 and $400, depending on the level of filter complexity, the manufacturer, and the specific product’s components.

Paying for a filter at a significantly lower price than the average may run the risk of the filter performing poorly or having a much shorter lifespan than others.

It’s worth bearing in mind, however, that filter price doesn’t always reflect quality. You can find some fairly good deals on filters that have a history of excellent performance, so always read reviews and learn about the manufacturer before making a purchase.

Regular Maintenance

If you were hoping to purchase an under-counter water filter that would work quietly behind the scenes for years on end, no maintenance required, you’ll be let down to know that these unfortunately don’t exist.

All under sink systems require regular cleaning and maintenance to ensure they continue to work properly.

Filters will need changing fairly often, which means factoring in the additional costs of doing so. A kitchen sink filter is an investment you’ll be expected to keep building on, so make sure you’re prepared for this before you make a purchase.

Is a kitchen sink filter right for me?

An under counter water filter is right for you if:

  • You currently spend a lot of money on clean, bottled water
  • Your home or business’ ingoing water contains a high level of total dissolved solids
  • Your tap water doesn’t taste or smell pleasant
  • You want to benefit from drinking cleaner water
  • You’re looking for a long-term, cost-efficient drinking water solution

Generally, an under sink filter is good for anyone who wants to drink cleaner, purer, better-tasting water.

If you’ve weighed up the pros and cons of a kitchen sink system against other filter models and decided that this one is best for your requirements, an under-sink water filter is for you

Frequently Asked Questions

Where can I install my filter?

Under counter filters are designed to fit in the space or cupboard area below your kitchen sink. As conventional under-sink systems come with kitchen-style faucets, your kitchen is the best room for installation.

However, you can install your system in your basement if this is more convenient. You can also connect your filter up to your refrigerator, ice maker or coffee machine, although it’s recommended that you store the actual filter in your under-sink space.

Can I install and change filters myself?

Yes, most people are fine to install their own under sink system. Your system should come with a detailed instruction manual and all the parts you’ll need for simplified installation.

You can find additional installation support on the internet, where there are plenty of step-by-step videos for general under-sink filter installation that you’ll be able to use in the fiddlier aspects of installation. Normally, your manufacturer will also offer live support, which can come in handy if you have questions about your specific filter model.

Changing your filters is a very simple task that you’ll definitely be able to do on your own. Most filters have a twist and click system that allows for them to be quickly removed and replaced.

What’s wrong with tap water?

There’s nothing wrong with tap water, per-se. Drinking your tap water won’t lead you to fall sick or be bad for your health. The water that comes out of your faucets has been treated for consumption at a water treatment center, removing any harmful bacteria that would make water unsafe to drink.

However, certain chemicals like chlorine are added to the water as part of the decontamination process. These chemicals are only present in the water in tiny amounts, but they can affect the taste and appearance of water.

Treating water also doesn’t remove all total dissolved solids from water. Contaminants like lead, arsenic, rust, sulfur, and even some bacteria often remain in water even after it has been treated. Again, these aren’t in high enough quantities to pose a health risk, but they do affect the taste and smell of drinking water.

How do I know what’s in my water?

You can find out what’s in your water by contacting your supplier and asking to see a drinking water quality report. You might already receive these in the post, but if not, the information should be available for public examination.

A drinking water quality report lists everything you need to know about your local drinking water’s quality. It will tell you where your water comes from – lakes, rivers, aquifers, etc. – and list the regulated contaminants in the water source, the potential health effects of drinking these, and contaminant levels in your local area compared to national standards. This makes it easier to determine the quality of your drinking water in comparison to the average water quality.

If you’re using well water, you’ll need to test your water yourself using a water testing kit to be certain of the contaminants it contains. Remember that while water filters do filter out many bacteria and contaminants, they won’t be suitable for more serious cases of well water contamination.

If I already have a water softener, do I also need a filtration system?

The answer to this depends on your water filtration goals. Water softeners only remove hardness-causing minerals from water, namely calcium and magnesium, which typically cause a build-up of limescale on water-based appliances and prevent water from lathering effectively. They don’t remove contaminants from your water.

If you’re looking to improve the quality of your drinking water, you’ll need to install an under-counter filtration system even if you currently use a water softener. This will remove contaminants like lead, bacteria and chlorine from your water, which your water softener won’t do.

Do I need an extra faucet for my filter?

Not all under-sink systemss require a faucet. If you’re buying a conventional filter, these tend to come with their own faucet, which will produce filtered water separately to your standard kitchen sink faucet. You won’t need to buy your own faucet for the filter, as the majority of systems will come with a faucet that’s designed to connect to your system properly.

A newer model of under-counter filter is the simple water filter, which doesn’t require a faucet. The filter is connected up to your standard kitchen sink faucet, and when the tap is turned on, any cold water that flows out will be filtered. Your hot water will not be filtered.

What system is best for me?

The majority of water filtration systems you can find online are slightly different in their make-up, although most will perform the standard water filtration duties. Choosing between one specific offering and another comes down to exactly what you want from your water filter.

Consider your budget, and why you want filtered water. Remember to take into account your water issues – do you have specific water safety concerns, or does your water contain a certain contaminant, like sulfur, that leaves a distinctly unpleasant taste or smell? Narrow your choices down to two or three, then read up on reviews to help you make a final decision.

Will I need an electricity source?

No, you won’t usually need to connect your kitchen sink filtration system to an electricity source. It’s your water pressure that powers a filter, so provided pressure is high enough for water to flow through at a consistent rate, electricity won’t be needed.

If your water pressure reads at 30 PSI or below, or you’re using a well source, you’ll need to purchase a booster pump to improve your water pressure.