Best Under Sink Water Filters of 2023

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Our editors independently research the best products online to produce this list. We may receive commission on purchases made from the links below but this will never affect our product choices.

Top 10 Best Under Sink Water Filters

  1. Frizzlife MK99 (Editor’s Choice)
  2. AEG 3-Stage Filtration System (Luxury Choice)
  3. Aqua Quality Kit (Best Value)
  4. Finest Filters System (Best Kit)
  5. Frizzlife SP99 (Best with Faucet Included)
  6. iSpring RCC7AK (Best 6 Stage)
  8. Finerfilters 50 GDP System
  9. Geekpure RO5-DI
  10. Waterdrop 15UB

If you live in the UK, the water flowing out of your tap is usually safe to drink. However, you don’t know what happens after the water is pumped from the treatment facility to your home. Maybe the treated water was exposed to lead, bacteria, odour, or other harmful contaminants in the plumbing system before it flows out of your kitchen tap. The truth is, you can never be too sure.

The obvious solution is to install a water filter under your kitchen sink. In this article, we’ll be reviewing the best under sink water filters, making it easier for you to find the best under sink water filter in the UK! Hopefully, after reading this, you will find the right one for your home, buy it and finally get rid of all those worries about whether you are drinking safe water or not!

Let’s get down to it, shall we?

How We Compared Sink Water Filters

under sink water filters collage

To find the right sink water filter we considered multiple factors, including:

  • Size and capacity
  • Flow rate
  • Water pressure
  • Faucet attachment
  • Odour removal and healthy minerals added
  • Waste vs pure water ratio
  • Certifications
  • Installation
  • Warranty

Our editorial team carefully researched and selected products that would suit a wide range of needs to take your kitchen experience to the next level. We set out this list after assessing customer reviews and evaluating pros and cons in line with the above comparison points.

Find more about our behind-the-scenes process here.

Under Sink Water Filter Reviews

Frizzlife MK99 (Editor’s Choice)

The Frizzle MK99 uses a two-stage filtration system that removes harmful contaminants such as chlorine, heavy metals, mercury, lead, carcinogens, chromium 6, and volatile organic compounds. However, this under sink water filter system preserves essential minerals such as sodium, calcium, magnesium, and potassium; this would make your drinking water taste better.  

What’s more, you can install this water filter in about 3 minutes, thanks to the auto shut-off design. Talking about the water flow, it can produce 2 gallons per minute at a pressure of 60 psi. If you’re not convinced yet, it’s compatible with a cold water line.

The water filter cartridge should be able to handle 1600 gallons of water before it’s due for a replacement. However, if you want the best results, we recommend replacing the cartridge after six months.

 Another great thing about this water filter is it’s not expensive, and you can get it for less than 100 pounds.

On the other hand, please note that this water filter may not be as effective as reverse osmosis filters.


  • Auto shut off design
  • 2 in 1 advanced filtration system
  • Fast water flow
  • Low budget and eco friendly
  • Easy to install


  • It may not be as effective as reverse osmosis filters
  • The cartridge may need to be replaced regularly

AEG 3-Stage Filtration System (Luxury Choice)

If you are looking for something over-the-top and do not mind spending a little more, then the AEG 3-Stage Filtration System might be perfect for you.

This is a three-stage reverse osmosis filtration system that can remove the smallest contaminants such as lead, chlorine, cysts, arsenic, and nitrates at the molecular level. It’s small and compact enough to fit under your sink, and it comes with an easy-to-read installation manual. It might be the best water under sink water filter in the UK.

It uses a hydraulic system to pump the water at a minimum of 2.7 bars through a partially permeable membrane. Another cool thing about it is that you can change the filter cartridge without turning off the water supply.

Unfortunately, it can only purify 55 litres of water per day, but the flow rate is two litres per minute. Besides that, it wastes a lot of water during the purification process; However, you can drain the wastewater and use it for non-drinking purposes.


  • Easy to install
  • Quick filter change
  • It’s very efficient
  • It doesn’t occupy a lot of space
  • Consistent flow rate and water pressure


  • Its volume capacity may be lower than what you prefer
  • It may produce more waste during the purification process

Aqua Quality Kit (Best Value)

The Aqua Quality Kit is the best under sink water filter in the UK that does not hurt your pockets.

This is a granular activated type of carbon water filter that works like a magnet to attract and retain contaminants and toxins through a process known as adsorption. It’s quite impressive, it’s one of the most affordable under sink water filters on the market, yet it eliminates up to 97 per cent of organic contaminants and toxins in your water. Still, it doesn’t remove healthy minerals that will improve the taste of your water.  

It weighs less than a kilogram for what it’s worth, and the filter can easily fit in your hand; this could be perfect for an RV or tiny home. The flow rate is 1.9 litres every minute with a maximum pressure of 120 psi. As long as the water temperature is between 0.6 to 30 degrees Celsius, it shouldn’t have a problem purifying the water.  

However, the carbon filter has a rated capacity of 5,678 litres, which is a decent number, but on average, the old filter needs to be replaced after six months. Also, this under sink water filter system is not compatible with plastic pipes.  


  • Low budget
  • Easy to install
  • High rated capacity
  • It removes odour and contaminants
  • It comes with a shut off valve


  • It may not be suitable for installing on a plastic water pipe
  • It might have a short filter replacement interval

Finest Filters System (Best Kit)

The Finest Filters System is an economically good choice for an effective under sink water filter.

For starters, this is an activated carbon filter block that is easy to install; you need to connect the filter to the pipe under the sink and drill a hole for the faucet. Once installed, the under sink filter will purify 5.2 litres of water per minute at a consistent pressure of 60 to 120 psi.  

Beyond that, what we like about this water filter is that it will make your tap water taste better. This is because it removes contaminants and toxins such as chlorine, lead, bacteria, mercury, dissolved solids and other heavy metals but preserves the healthy minerals. And in case you did not know, it will cost you less than 20 pounds, and a faucet is included in the accessories?

On the downside, this water under sink water filter doesn’t prevent limescale build-up, and if you want to prevent limescale, you should buy a water softener. Other than that, the saddle shouldn’t be connected to a plastic pipe. 


  • Easy to install
  • It preserves healthy minerals
  • Consistent flow rate
  • No water goes to waste
  • It comes with a quality faucet


  • It may not prevent the build-up of limescale
  • It may not be suitable for plastic pipes

Frizzlife SP99 (Best with Faucet Included)

How about a three-stage reverse osmosis water filtration system that can remove 99 per cent of the contaminants? It doesn’t just remove bacteria, germs and other harmful contaminants, but it can also soften your drinking water.  

The water flow rate is 2 gallons per minute at a consistent pressure of 60 psi; this should be enough to fill a 300 ml cup in less than 2 seconds. Surprisingly, it doesn’t come with a storage tank but a low water wastage ratio. What’s more, this under sink water filter has a longer filter life expectancy than most carbon and ultrafiltration systems; if you want to change the filter cartridge, you don’t need to get rid of the outer case.

Its biggest shortcoming will cost you more than most activated carbon blocks. On top of that, you need to drill a hole under the sink to fix the filter tap.


  • It removes 99 per cent of contaminants
  • Fast water flow and consistent pressure
  • Easy to install
  • Long filter life
  • Low water wastage


  • There might be chances that you will encounter a leaking faucet
  • You may need to drill under the sink

iSpring RCC7AK (Best 6 Stage)

The iSpring RCC7AK has undergone rigorous testing for cycle resistance, pressurization and air leaks and received the NSF/ANSI 58 certification. In other words, this is an RO filter that can eliminate 99 per cent of dissolved solids and bacteria in your water.

What makes it so efficient? Because it’s a 2 in 1 reverse osmosis and carbon filtration system that is designed to purify your water through 6 different stages. In addition to that, it can soften your water and inject healthy minerals after the filtration process to improve the taste.

The ISpring RCC7AK under sink water filter has a holding tank with a capacity of 3.2 gallons, but it can filter 75 gallons of water in a day. Another cool thing is that it uses transparent filter housing so that you can know when it’s time to replace it.  

On the other hand, it’s not small and compact, so you should expect it to occupy a lot of space under your kitchen sink. It’s also one of the most expensive water filters on the market.


  • Multi-stage filter with reverse osmosis 
  • It adds healthy minerals
  • Easy to install
  • It’s certified by NSF/ANSI
  • It’s durable


  • It might be bigger than most units 
  • For every gallon purified, it might produce waste of up to three gallons of water 


This carbon filter is the best under sink water filter in the UK for people who don’t want to drill a hole under the sink or hire a plumber during installation as it can be done in about three minutes. It should be able to fit 3/8 inch or 1/2-inch cold water lines; no wonder it’s known as ‘ice pure’.

The ultrafiltration system is designed with small minute microns to purify the water by removing impurities such as chlorine, rust, and heavy metal minerals. Even more impressive, it can eliminate bad taste and odour even if you throw a rotten egg in your water supply.  

The maximum flow rate is 2.5 gallons per minute at 60 psi. Its expected lifespan is 20,000 gallons or five years on average; this is longer than most carbon water filters.

It turns out that its strength is also a weakness since this ultrafiltration system wouldn’t be effective if you connect it to a hot water line. Besides that, it doesn’t remove more contaminants than reverse osmosis systems; but it can still get the job done exceptionally.   


  • Easy to install
  • Convenient for cold water
  • High flow rate and water capacity
  • Long filter life 
  • NSF certified filter


  • It may not be suitable for hot water
  • It may not be as effective as an RO filter

Finerfilters 50 GDP System

The Finerfilters 50 GDP System is another model that we highly recommend.

This filtration system comes with all the tubes pre-connected and most of the parts pre-installed. Not to mention, the instructions manual is very thorough. Furthermore, it should be easy to install, although you may need to drill a hole under the sink.  

Once installed, the water in your supply line will go through 6 stages to make it safe for drinking. The water will pass through a sediment filter to remove large sand, dirt, and dust particles at the first stage. Next, the water will go through stages 2 and 3, which involve the adsorption process using an activated carbon filter; this helps remove chlorine, pesticides, odour, and volatile organic chemicals.

We’re not done yet! The water will be purified through a reverse osmosis membrane. At this stage, 99 per cent of the contaminants and bacteria can’t escape into your faucet water. However, just to be sure about the result, the water goes through another carbon filter in stage 5.

Finally, the high-quality filtered water is enriched with healthy minerals to improve the taste before drinking it. This water filter system should purify 190 litres of water per day at maximum capacity.  

Despite its impressive efficiency, we find it is bulky, and it will take a lot of space under your sink. However, that should not be a deal-breaker.


  • 6 stage reverse osmosis purification
  • It comes with an activated carbon filter
  • It can last for years
  • Easy to install
  • It stores filtered water


  • It could be heavy for some people 
  • The membrane filter may need to be maintained more often

Geekpure RO5-DI

The Geekpure RO5-DI is an excellent option if you want a mid-range budget reverse osmosis system combined with a carbon filter. 

It meets all the criteria under NSF/ANSI standard 58 certification, and it can filter water to the smallest micron. It can purify your water through 6 stages and make it taste like bottled water, or even better.

Another thing that you will probably like about it is the 12 litres per hour flow rate at 60 psi. Sure, it can only filter 75 gallons or 283 litres in a day, but that is more than enough drinking and cooking tap water for a family of 4 or 5 people. Additionally, it comes with a lead-free separate faucet and a 10-litre holding tank.

Unfortunately, installing the fittings could be a headache, and you may be forced to make some plumbing adjustments.


  • High maximum flow rate
  • Advanced 6 stage reverse osmosis filtration
  • Long filter life 
  • It comes with a lead-free faucet
  • NSF/ANSI certified


  • It could be bulky for some customers 
  • It could be tricky to install

Waterdrop 15UB

Last but not least, the Waterdrop 15UB is another great choice for your under sink water filter.

At first glance, you will notice that the feed water adapter on this water filter system is made of metal. This means it’s designed to last longer than plastic units. How long exactly are we talking about? The average lifespan of this device should be 16,000 gallons which means at least five years.

However, this is not a reverse osmosis system or a carbon filter system. It’s an ultrafiltration device that uses hollow fibre membranes similar to an RO filter but with larger pores. Of course, it can remove most water contaminants such as chlorine, mercury, lead, fluoride and arsenic. Because of its unique design, it can also add healthy minerals to your crystal clear drinking water.  

What about installation? It uses a twist and lock design that makes it possible to install in less than 3 minutes. This would be convenient for your kitchen, office or RV.

It’s almost perfect, except it has one gallon per minute low flow rate. Unfortunately, we’ve seen water filters with a better flow rate.


  • Easy to install
  • It’s small and compact
  • It adds healthy minerals
  • It can last for years
  • Certified by WQA


  • It may have a low flow rate
  • It may not be as effective as RO filters 

Why Do You Need a Water Filter? 

In the UK, tap water is generally safe to drink because it’s treated at the water processing plant before it’s delivered to your home. However, that doesn’t mean that the tap water you drink can’t be contaminated when it reaches your residence. For instance, we’ve heard cases of treated water getting contaminated by lead leached from old pipes; you probably wouldn’t know if it happened.

However, if you use a water filter in your kitchen, you can get rid of any contaminants that may have leached into your water after it was pumped out of the water treatment plant. Even if no contaminants are found in your water, it’s better to be safe than sorry.  

Another reason you need a water filter is to make your water taste better. Yes, a sink filter system can remove chlorine or unpleasant odour from your water and add healthy minerals to make it taste like the closest thing to Nirvana.

Types of Water Filter

Reverse Osmosis

Reverse osmosis water filters break down water at a molecular level. The water is pumped through a partially permeable membrane with pores so small that toxins and minerals will be trapped. That means a reverse osmosis water filter should be able to eliminate at least 99 per cent of water contaminants, including bacteria, fluoride, chloride, calcium and magnesium.

The best reverse osmosis water filters are designed with multiple layers of filter membranes to produce crystal clear purified tap water that is safe to drink. However, most reverse osmosis water filters are expensive, but they’re the most efficient type of water filter.

Besides that, reverse osmosis water filters have a high ratio waste stream. That means a high percentage of water that passes through the filter membrane won’t end up on the other side as treated water. On the bright side, you will drink the water knowing it has gone through the most rigorous purification process.


Ultrafiltration water filter is almost similar to a reverse osmosis water filter. The difference is ultrafiltration relies on hollow fibre membranes with larger pores than a reverse osmosis filter. That means an ultrafiltration water filter won’t remove as many contaminants or minerals as a reverse osmosis filter.

An ultrafiltration system will remove bacteria and germs, but it will preserve healthy minerals in your water. Because it doesn’t filter water at the molecular level, an ultrafiltration system has a low ratio waste stream than a reverse osmosis filter. Also, it doesn’t require too much pressure to work, and you can install it on the main faucet.

Carbon Filters

Carbon filters have tiny pores that attract contaminants out of your water through a process known as adsorption (not to be confused with absorption). In other words, activated carbon filters work like magnets to attract and bind with contaminants at the molecular level.

The best carbon filters should remove chlorine, bacteria, iron, fluoride, sodium, calcium, cysts, mercury and odour. However, different carbon filters don’t have the same effect, so you should be keen to check the micron size noted by the manufacturer.

A filtration system in the kitchen

Better yet, if you want the best water filter, choose a unit that incorporates both reverse osmosis and carbon filtration technique.

How to Choose the Best Water Filter

Size and Capacity

How much water do you need to filter every day? If you’re living alone, you could choose a simple sink water filtration system that can produce 20 to 50 gallons per day. But if you live in a household with many occupants, we recommend a water filter that can deliver 50 to 80 gallons daily.

However, most water filters that can filter more than 50 gallons per day require more space under the sink, especially if they’re designed with a holding tank. The silver lining is that water filters with high capacity can last longer without replacing the cartridges.

Flow Rate

Most under the sink water purifiers need to be connected to the main faucet so you can access the filtered water. The best water filter should deliver a consistent water flow so that you won’t notice any slight change after you’ve installed it. But how do you know if it will be up to par? It’s simple; just check the flow rate of the water filter before you purchase it.

Most decent water filters have a flow rate of 0.8 to 2 gallons per minute; anything less than that and it will take too long to fill your cooking pot with water. The flow rate of your home is also affected by some things. First is the pressure of the water supply into your home and the number of open water taps.

Water Pressure

As we’ve previously mentioned, a better-than-average flow rate won’t do you any good if your water pressure is too low. In addition to that, if you have a reverse osmosis system, you will need at least 40 to 60 psi to be effective. This is because RO filtration systems rely on high pressure to pump the water through a partially permeable membrane.

However, carbon filters and ultrafiltration systems don’t require water pumped at high pressure, similar to RO filters. Then again, it’s better to have a water filter with a high water pressure than lower water pressure.

Faucet Attachment

Do you want a water filter connected to your main faucet, or do you prefer a separate faucet? Most reverse osmosis under sink filters come with a separate dedicated water filter. Using it shouldn’t be inconvenient if your kitchen sink is designed with pre-fabricated holes. However, some kitchen sinks need to be filled with holes to accommodate a separate faucet.

Alternatively, it’s possible to replace your kitchen sink tap with the faucet that comes with your water filter.

Odour Removal and Healthy Minerals Added

Don’t you just hate it when you drink tap water and smell a weird odour? Chlorine is usually the most common culprit that causes your water to odour and tastes bad. Fortunately, most reverse osmosis and carbon filters should be able to remove chlorine and other contaminants that cause your drinking water to have an odour.

But removing the odour is not enough; you also want your water to taste like bottled mineral water. That shouldn’t be a problem if your under sink system can inject healthy minerals into your purified ready-to-drink tap water.

Waste vs Pure Water Ratio

Of course, most people don’t want an under sink water purifier that will waste too much water, causing your bills to skyrocket. The problem with most RO filters is that you lose a lot of water during the purification process. It’s unbelievable that some RO systems can waste as much as 5 gallons for every 1 gallon of filtered water.

However, modern RO filtration systems use a permeate pump that improves the water pressure to reduce waste. This is helpful to reduce the waste vs pure water ratio to 3:1 or even as low as 1:1. Better yet, some modern reverse osmosis filters will give you the convenience to utilize the flushed water for non-drinking purposes.


The best under counter water filters are certified by independent organizations that assess the industry standards. For instance, if you want to know if your water filter can remove chlorine, you should confirm whether it has passed the ANSI/standard 42 certifications.

Additionally, you should check if the water filter you want to purchase has been tested and certified to remove lead and volatile organic compounds. What’s more, you should consider water filters that have the NSF/ANSI standard 401 certifications; this means you’re under a sink water filter system that can remove pharmaceutical drugs from your water.

Otherwise, some of the most common certifications for water filters are done by (Water Quality Association), WRAS (Water Regulations Advisory Scheme) and NSF International (National Sanitation Foundation).


If you don’t want a headache when installing a water filter, you should consider a unit that doesn’t require plumbing. Most water filters installed directly on the main faucet are easy to install; you can get it done in less than 5 minutes without consulting a plumber.

However, reverse osmosis water filters that come with a separate faucet can be complicated to install.


Price and Warranty

Some of the most efficient under sink water filters have a price tag of between 100 to 400 pounds. Sure, you can get a low-budget water filter for less than 50 pounds, but don’t expect it to be as efficient as an RO filter.

Another important thing that you need to check is the warranty; the best water filters should have a manufacturer warranty of between 3 to 5 years.

How to Maintain Your Under Sink Water Filter

If you want to prolong the life of your water filter system, you need to maintain and clean it with precision. Here are a few tips on how to maintain your under sink water filter system at home:

1. Make sure you clean the interior of your water filter using warm water at least once per week. However, avoid using strong cleaning products because toxins contaminate the water.

2. When cleaning your water filter, don’t forget to sanitize the line, cap assembly, faucet and water dispenser.

3. Most water filtration systems include a control unit that will tell when you need to change the filter cartridge. Moreover, you can know when to change the filter cartridge if the water starts to taste weird or you notice a bad smell. If the filter cartridge is due for a replacement, make sure you get the job done as soon as possible, or else it will become clogged.

4. When changing the filter cartridge, make sure you inspect the O-rings for any signs of leakage.

5. If you want to increase the longevity of your water filter, install a water softener in your piping system. This will reduce hard minerals in your water, such as magnesium and calcium, that could shorten the lifespan of your filtration system.  

6. Like most appliances, filtration systems are not designed to last forever. If your water filter is old and it has outlived its lifespan, you should replace it as soon as possible, or you will risk drinking contaminated water.

Common FAQs

Which is the most effective water filter system?

A. A reverse osmosis system is the most effective water filter, hands down. An RO filter removes toxins and contaminants at the molecular level.

Where should I install my water filter?

A. Most filtration systems are designed to be installed under the sink inside the kitchen cupboard. However, you can install some types of water filters on the countertop.

Do I need to install an under sink water filter if I have already a water softener?

A. Yes. A water softener is designed to remove hard minerals from water, but it doesn’t eliminate other contaminants like bacteria and germs. If you want clean and safe drinking water, you need to install a water filter, even with a water softener.

Do I need electricity to operate a water softener?

A. Most under the sink water filters don’t rely on electricity to purify water. Instead, they use water pressure and gravity to pump the water.

Can I see the purified water in my water filter system?

A. It depends on the design of your water filter. However, some water filters have transparent filter housings that let you see the water during the purification process.

What is the average lifespan of an under the sink water filter?

A. Most under the sink water filter systems have an average lifespan of 10 to 15 years, although they need to be regularly maintained to improve their durability. But if we’re talking about water filter cartridges, you need to replace them after six months or one year; it depends on the manufacturer’s instructions.


All the water filters we’ve reviewed in this guide are top-shelf quality, making it easier for you to find the under sink water filter system that suits best your needs. 

It all comes down to your preference, but if we had to choose the overall best under sink water filter kit in the UK, we would pick the Frizzlife MK99. This is because it can eliminate up to 99 per cent of toxic contaminants in your water and pump tap water at a flow rate of 2 gallons per minute. For that reason, we think the Frizzlife MK99 is the best under sink water filter in the UK.

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