Let’s start this article off by explaining what an under sink water filter is – and you won’t be surprised to know that the name gives you most of the answer! But there is a little more to it than that and it is important to understand what they are before considering whether to buy an under sink water filter.
These water filter systems sit underneath the sink and are connected to the cold water pipe, taking water into a tube and passes it through the filter, up to a special faucet. This happens on-demand and doesn’t use a tank, and so reduces waste and improves energy efficiencies. Its faucet is separate to the standard ones on your sink, allowing you to use unfiltered water whenever you need to, such as for water plants.
These under sink water filtration systems are getting more and more efficient all the time and now offer similar levels of contaminant removal to what reverse osmosis systems do, which wasn’t something you could say a few years ago.
Our Top Picks
Best Under Sink Filters of 2021:
Under Sink Filters that are worth mentioning:
Our Top 10 Best Under Sink Water Filters
We’ve taken the time to put together a list of the ten best under sink water systems so that you can choose from the best on the market. Please see below a brief description and review of each product, including why we believe they are a great choice for any household.
1. CuZn UC-200 Under Counter Water Filter
The CuZn UC-200 gets one of the strongest reviews from our team of experts for a few reasons. Put simply, there are many reasons why this simple, affordable water filtration system is worth choosing.
Performance:
For a start, it’s an affordable piece of kit that filters water to the level you would expect, ensuring you have a safe, clean and great tasting water supply. Where this model does stand out from the crowd is its long-lasting water filters, which can work for up to 50,000 gallons of water, a phenomenal amount compared to many others on the market.
Installation:
Furthermore, installation is simple, connecting it to the cold water line under your sink, with everything you need arriving in the box. For anyone new to DIY, simply follow the instructions and you should cope. The support documentation is quite helpful too.
Size:
Obviously, to perform this well there are downsides and with this one, the main issue is size – it is a bit bigger than other under sink water filters, so may not be suitable for very small cupboards.
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2 iSpring RCC7AK 6-Stage Drinking Water Filter System
The final water filter system that we want to tell you about is this budget-friendly system from iSpring, a leading manufacturer in the world of water filters and a trustworthy solution for drinking water.
Performance:
You will get incredibly pure water with this iSpring water system and you can trust the results, thanks to it being NSF certified against the relevant NSF standards. It will remove 99% of harmful contaminants in the water, including chlorine, fluoride, bacteria and viruses, as well as 98% of lead.
It utilises a 5-stage reverse osmosis filtration system including 3 pre-filters (sediment mesh, activated carbon core and a carbon block). After these pre-filters, the water is sent through a RO membrane with 0.0001 micron pores.
Waste:
Where this system from iSpring falls down is in its wastewater ratio, which at best comes down to 3:1. This is pretty average for the systems on our list but by no means the best, so if you have low water pressure or problems with your water supply then you may need extra equipment.
Remineralization:
One of the best features of this under sink system is the remineralization process, which is the 6th stage. Thanks to it being so great at filtration, both healthy minerals and bad minerals are removed. This remineralization stage helps add back in those healthy minerals including calcium and magnesium. This means that your drinking water will be better for you.
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3. Clearly Filtered Kitchen Faucet Filtration System
A fantastic solution from ClearlyFiltered makes it onto our list of best under sink water systems for the primary reason that this is so quick and easy to install and yet still filters like the best on the market.
Installation:
You simply connect the water lines and it’s ready to go, however, it is important to note because of this ease of use, it doesn’t have a bypass valve, so when you turn the cold water supply on, you will use the filter.
Filtration:
As a filter system, it performs well, removing well over 200 contaminants from the water supply including chlorine, meaning you get great smelling and tasting water, as well as safe and healthy water. The filter lasts about 1 year depending on your usage and you can connect this filter to your existing faucet because it connects straight to the water line.
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4. Waterdrop 15UA Under Sink Water Filter System
One of the more affordable models on our list, a lot of care and attention has been put into the design of this under sink water filter because it only has one part, compared to others having multiple cartridges.
Performance:
This doesn’t mean it lacks any of the filtration power, as it has a 5-stage system that removes heavy metals and fluorides, as well as an activated carbon block improving taste, smell and safety of the water.
Installation:
This model utilises your existing faucet if you’d prefer and doesn’t require any kind of electricity connection, so can be used in remote or off-grid settings. The filter lasts around two years depending on usage and is relatively cheap to buy.
Hot water:
However, what we have found is that these filters cannot be used with hot water and should you wish to use a separate faucet, you would need to buy one separately, potentially adding to the cost.
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5. Aquasana AQ-5300.55 3-Stage Under Sink Water Filter
We know this model is at the lower end of the price range but we have included it before despite its price, it is still a quality filter, often producing clean and great tasting water as well as more expensive models.
Performance:
It will remove the majority of harmful bacteria and heavy metals from your water supply, making for clean, safe water for you and your family. If you are likely to put this in the kitchen or primary sink, then you can get drinking water, cook or clean with purified water.
Installation:
It only takes a few moments to install, letting you start getting clean water almost immediately. The support is good and in the unlikely event that you need professional help, it will be very easy for any plumber.
Maintenance:
With an attractive faucet arriving as standard, the option to choose a different one when you order and an incredibly easy to perform a filter change (you simply twist it out and twist a new one back in), there isn’t much to dislike here.
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6. APEC WFS-1000 3 Stage Under Sink Water Filter
A popular product in the under sink water filter market is up next, with this APEC top tier system producing a 3-stage filtration system that gives your household high rated, clean and healthy water that will also taste amazing.
Water pressure:
It is also important to note that this one doesn’t impact on the water pressure, a concern for many looking at water filters as any on-demand water filter will generally reduce the flow. Not the case here, with feedback suggesting you don’t suffer from low pressure.
Installation:
In terms of installation, you won’t struggle with this, everything needed arrives in the box, ready with pre-drilled holes so you can mount it on the wall easily enough.
Design:
Unfortunately, you can only get the one style of faucet with this model, so for those wanting a specific design or finish, you may be disappointed.
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7. Doulton W9330958 SuperCarb Under Sink Water Filter
This model from Doulton uses a complex four-stage water filter process to really provide the highest quality water that is clean and safe. Eveything you want from a sink filter providing drinking water.
Filtration:
The first stage uses a carbon block filter to focus on bacteria, odours and taste, followed by a second antibacterial filter. After this phase, they have another carbon filter which this time removes chlorine and then a fourth filter aimed at preventing heavy metals from getting into the water supply.
Maintenance:
An effective system that is well made and will last longer than the majority of under sink water filters on the market. A filter change won’t take long or require significant knowledge to complete.
Installation:
One downside of this system is that you may need to buy extra parts to install it correctly, not something we particularly like, but it is a fantastic sink filter. This may mean it’s worth the choice, particularly if you’re comfortable with plumbing in new systems.
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8. Filtrete Advanced Under Sink Water Filtration System
We’ve included this under sink water filter system on our list because it is incredibly cost-effective and so for those on a budget, you can still get clean and healthy water.
Performance:
It doesn’t use a separate faucet, you simply connect it to the cold water supply and any water you use will have to pass through the under sink filters. Don’t mistake cheap for poor results, as you will still remove up to 99.99% of sediments in the water and 96.6% of odours and more.
Installation:
As you’d expect from a simple under sink filter, installation isn’t an issue, taking less than 30 minutes for most.
Maintenance:
The filters should last on average around 6 months, or 10,000 gallons of water, depending on how heavy the water usage is in your household.
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9. Home Master TMAFC-ERP Under Sink Water Filter
An under sink water filter now that has some industry-leading performance and features, making it a must-have for many households. Home Master is an NSF listed manufacturer which means they’re products have been tested and in most cases NSF certified, making them one of the best under sink water filter manufacturers.
Performance:
To start off with, you will get an improved flow rate thanks to the way it uses energy, requiring zero electricity. Add in the fact that it is so efficient that it has a waste ratio of 1:1, compared with some good systems on here that will go as high as 5:1 waste to purified water.
Filtration:
This system from Home Master uses 3 filters: a sediment filter, carbon filter and coconut shell activated carbon filter, as well as the Reverse Osmosis (RO) membrane. All of this means you will be getting water which has had 99% of solids, chemicals, heavy metals and harmful contaminants removed. With this kind of filtration, you can happily use your household supply as drinking water.
Installation:
Yet another RO machine that is easy to install, coming with everything you require in the box. Installation takes approximately 50 minutes and most people will be fine with it, but if you are very new to drilling and DIY, you may want to get some additional support.
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10. iSpring US31 3-stage Under Sink Water Filtration System
Next on our list is from one of the leading filter manufacturers, iSpring and their 3-stage under sink water filter system.
Performance:
It has one sediment and two carbon block filters which will stop harmful contaminants such as heavy metals from getting through into your water supply. This is quite common for these under sink systems to utilise a 3-stage water filtration system as it really does clean up your water, making it safer for you to use as drinking water and kinder to your skin and clothing.
Installation:
It comes with a reasonable faucet that wouldn’t look out of place in most kitchens and can be installed at home without the need for professional support. You can even use a different faucet if you want to which is a big bonus for this product.
Flow Rate:
Away from the fantastic filter, it does suffer from a relatively low flow rate, only 1 GPM, which may be too slow for some people and this is part of the issue with on-demand filtration, as it must actively filter as you run the water.
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Why do you need one?
There are a few reasons why choosing an under sink water filter is the right choice for anyone wanting a filter system in their household.
Firstly, these can be used in small spaces due to the lack of a water tank and so are perfect for those with limited space, such as a flat. Secondly, choosing one of these filters is generally a cost-effective solution because the upfront costs are relatively low and so are the maintenance fees because filters aren’t expensive.
Aside from the space and financial implications, the flexibility that these filters bring means that you can promote drinking more water in your household, an important part of a healthy lifestyle and choose when to use filtered water or not.
We firmly believe that reducing waste and damage to the environment should be at the forefront of decision making and with an under sink water filter, you remove wastewater, stop buying countless single-use plastic bottles and can choose when to use filtered water. Every aspect helps reduce the impact your water supply as on the environment.
The pros and cons
With so many types of water filtration systems out there, it is important to understand the pros of choosing an under sink water filter and why they may not necessarily be the best choice for your specific situation.
Pros
Let’s start off with all of the reasons why an under sink water filter system would be a great choice for you.
Quality and Taste
The obvious place to start is that this type of filter system will offer you higher water quality, without the contaminants and harmful bacteria that even modern tap water can contain. Particularly important in the kitchen, where your family will drink the water, use it to cook with and give to pets, you want to make sure this water outlet provides only the safest, healthier water.
Not only improved water quality, but the improved taste comes as a result of choosing an under sink water filter, helping to remove those smells and tastes that put people off drinking water. By making it more appealing, you will help your household drink more water and live a healthier lifestyle.
Environmental Impact
This type of filter reduces the impact on the environment in a few different ways, starting with minimal waste due to not using a water tank. As the water is filtered on-demand, you won’t have any wastewater being sent back, reducing water usage. Furthermore, you won’t need to buy bottles of mineral water at the shops because you can refill your bottle at home with clean, refreshing water.
Space Saving
There are no big storage requirements with an under sink water filter, as it doesn’t have a tank. This means it will fit in more modest properties, hidden away under the sink. As it doesn’t filter the entire household, you don’t need large pieces of equipment.
Money-Saving
These filters are relatively inexpensive to purchase and maintain due to cheap filters and easy maintenance. Add in the fact that they can be installed at home without professional help and you’ve got a great solution at a budget-friendly price.
Cons
There are not many cons to choosing an under sink water filter but it is important to be aware of the limitations, in case they form part of your original reason for purchasing a filter system.
Only for single outlets
These filters are designed to fit under the sink of a specific outlet, such as the kitchen sink and not offer a whole house water filter solution. This may be okay for many of us but for those who want to have filtered water in multiple locations, you would either need multiple versions of this or another whole house system.
Requires a separate tap
Most under sink water filters have its own faucet for the clean filtered water it provides, which may put people off. There are ways around this, such as getting a three-way tap installed that is connected to the other water connections. The best under sink water system may require extra installation costs because of this.
Well Water
For those that still utilise well water, we would suggest looking specifically at each of the sink water filters available to make sure it works with your supply. There are some that require greater water pressure or potentially not provide enough filtration.
Removal of healthy minerals
Some of these under sink water filters are so impressive that they remove almost all minerals, whether good or bad. This means you will lose some of the minerals found naturally in your water supply, or added by the water company. Some of the high-end sink water filters offer remineralization but this comes at an increased cost.
Three Types of Under Sink Water Filter
There are fundamentally three types of under sink water filter system that you can choose to go for, with key differences that are important to be aware of.
Under Sink systems with separate faucet
This is the standard filtration system for under the sink, whereby it is attached to the cold water line and filtered water comes out of a separate faucet. The main benefit of this is that you can choose to draw either hot water or cold water that is unfiltered, for example, if you wanted to water plants. This improves the lifespan of filters which reduces the cost and maintenance requirements.
Where this system falls down is that it can be harder to install, as well as requiring an extra hole on your kitchen sink/countertop. It isn’t as simple a sink filtration system as the one below.
Under Sink system with the same faucet
This system is very similar to the one above where it connects to the cold water line but utilise the existing faucet on the sink. This simple under sink water system is great for those without an extra hole for an additional faucet in your kitchen sink or those who want a quick and easy system to install. In most cases, this option won’t require professional assistance which reduces the cost and effort.
However, it is important to note that these under sink filters have the shortest lifespan as all water gets filtered through, even if you don’t really need it to. You also have to be careful that some filters don’t work well with hot water and if you forget to turn the filter off, you can ruin the filter and have to buy replacement filters.
Under Sink with Reverse Osmosis systems
The most effective filtration systems you can choose from are the ones that have a reverse osmosis filter. This is incredibly efficient at removing harmful contaminants and flushes them away as wastewater. You will often find that these use a separate faucet, so keep that in mind when researching these filters.
As highlighted above, the positives here of reverse osmosis systems (RO systems) is that you will get almost pure water, ensuring you and your family have clean, safe water. However, these systems are more expensive, require more effort to install and can waste plenty of water. Thanks to technology, there are some fantastic new reverse osmosis systems (RO systems) out there that reduce waste and bring the price down but think about whether your budget can stretch to these and whether you need the high-performance levels they offer.
Key considerations
There are some key considerations to be aware of when trying to purchase an under sink water filter. It can be a complicated and at times confusing world to be involved in, but with these key points in mind, you can make sure you get the perfect system for your household’s needs.
Filtration performance
Perhaps the most obvious consideration and reason for buying one of these units and that is the performance of the filters. All will be very effective at removing harmful contaminants but depending on the type of filtration, such as carbon filters or reverse osmosis, they will offer different performance levels. For example, reverse osmosis systems (RO systems) are incredibly effective at producing purified water.
Do be aware that the greater filtration, the greater the impact it may have on flow rate, so if you have a low flow rate already then be careful with getting a system that reduces it even further. Likewise, make sure that the system you choose is NSF certified or NSF listed, as it adds extra trust and reliability.
Water Pressure
As mentioned above, filtering systems can affect the performance of the water supply based on the pressure and flow rate. You should check the water pressure that is currently available to you and then see in the review whether the under sink water filter you want to buy, has any negative effects.
Cost
An obvious one but still important – the price you can afford to pay, or want to pay will determine the type of system available to you. Whilst the most efficient ones will cost in the region of $200 plus, and even then the biggest units pushing double that, it doesn’t mean you need to go for that.
Think about the features and performance you need and see what price these come out at. If they fall within your budget then great news but if not, you may need to rethink your plans.
Waste Water
An unfortunate side effect of a reverse osmosis system (RO system) is the wastewater vs pure water ratio. These will vary a great deal, with the average reverse osmosis system (RO system) around 3:1 but it does vary a great deal, with some systems wasting a massive 5 gallons for every 1 gallon of purified water. However, some are close to 1:1 as a result of fantastic new technology and extra pumps.
Installation and Maintenance
The current range of systems on our list are relatively easy to install, even for novices but should you have any concerns, then get a plumber or experienced person to help you with your under sink water filter installation.
Where the bigger consideration should be, is with the maintenance requirements. You definitely don’t want to have to crawl around trying to change filters in awkward and annoying places all of the time. So aim for filters that have as long a life as possible and effective RO membrane that will last for multiple years. Fortunately, the majority of systems now offer this kind of performance.
Under Sink Vs Countertop Vs Whole-house
There are fundamentally three ways that you can provide your family with clean, safe water for drinking water, cooking and cleaning. These are conventional under sink filters that we have discussed here and the other two: countertop and whole-house. As a result, we have put together some key differences between the three, so you can get an overview of each. We also have detailed pages on each option if you want to read further.
Installation
- A conventional Under sink filter (sometimes referred to as under counter water filter systems) are installed below the sink inside the kitchen cabinet
- Countertop water filters are installed on the side, taking up space when compared to a sink filter
- Whole-house filters are installed at the point of entry for the water supply, providing filtered water to the entire house
As you can see, the difference isn’t a great deal between an under sink filter and countertop filter, but the whole-house will require a significantly bigger amount of installation time and effort, as they are more complex systems. However, the benefits may well outweigh this added time and cost depending on your household needs.
Size and Capacity
- Under-sink filters offer a range of sizes and capacities, normally larger than countertop versions thanks to being hidden away which means adding capacity
- Countertop water filters will be designed to be compact and space-saving, which ultimately leads to a reduced capacity
- Whole-house filters will have a far greater capacity, thanks to their intended purpose of filtering water for the entire house. You also don’t want to have to buy replacement filters too often, so they are made to last many years
The biggest consideration here is on the capacity you need for filtration. Most under sink filters can process anywhere from 5000 up to 50000 gallons of water before needing replacement filters, depending on the model used. However, whole-house systems are designed to process anywhere up to 1 million gallons of water. So if you want clean, safe water for multiple faucets or a busy household, this may be the way to go.
Type of filtration
- Under sink filters will utilise multiple filter cartridges, including activated carbon filters to remove harmful contaminants. The more advanced versions will use a reverse osmosis (RO system) system to make your water even purer
- Countertop water filters offer a greater range of filtration options including gravity and electrolyte. Each one has its own particular benefits and is worth investigating should space or budget determine countertop is the way to go
- Whole-house filters are designed to filter a significant amount of water without impacting the flow rate too much and as a result, will employ more basic filtration methods, such as carbon filters. They are unlikely to utilise a reverse osmosis system (RO system) given it would be a waste of resources
Ultimately, your buying decision should be based on what you want the filter to achieve. Are you after clean, safe drinking water from a particular faucet? Or do you want safer, cleaner water for the entire household.
Installation Guide
Each under sink water filter will come with its own installation guide and customer support. This is because each one will have its own minor requirements, but in general they all follow the same steps that we will detail below:
- Ensure that the cold water supply is shut off using the shut-off valve and remove the water pipe from the valve.
- Map out the area underneath your sink that the filter will need to go. Once this is done, you can then install it as per the instructions provided by the manufacturer
- Insert the water pipe into the in section of the water filter
- Insert another piece of pipe or tubing between the out part of the filter and the faucet
That is pretty much all there is to it!
We would put a maintenance guide here as well but the honest answer is that there is minimal maintenance needed, except for replacing the filters. As a result, check out the reviews and manufacturers guides on the maintenance needed. Ideally, you will choose a system that lasts long enough to make replacement filters a rare occurrence, at least 6 months to a year, or even longer in some cases.
Summary
We have taken the time to put together this review page because we believe under sink water filters are a fantastic choice for anyone wanting to get filtered water at a specific sink in your house, but perhaps lack the space for larger tanks or whole-house systems. With every purchase you make, look at the key requirements for your specific household and map them against the key features and benefits of each system. That way you will ensure you shortlist the most effective options.
You will get high water quality, clean and safe water for your family and a reasonable price, making these a great investment over the long term.
So why wait? Look for the perfect filtration system today and get that healthy, safe water you have been waiting for.
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