7 Best Under Sink Water Filters (Reviews & Complete Buying Guide For 2019)

Under sink water filters are an excellent option for filtering. They have excellent efficiency and are improving all the time in terms of the amount of contaminants they can remove from your faucet water.

Under sink filters have the added bonus that they don’t produce waste water. This differs from most reverse osmosis filters in that they do produce wastewater.

In this guide we discuss the best under sink water filters this year. It is a comprehensive guide not only to what are currently the best filters available on the market, but exactly how is type of filter works and the benefits and downsides to using one.

If you are already looking for an under sink water filter, then we are sure you’ll find this guide useful in deciding which is the best option for you and your home.


Best Under Sink Water Filter Reviews

Why Under Sink Filters Are Such A Good Option?

Using a filter based under your sink is now a great option as this type of filter has quickly caught up to reverse osmosis as the only option to greatly reduce unwanted contaminants in your water.

Previous models of this equipment would use a carbon filter to stop contaminates. Modern designs of the under sink filter now use a variety of different techniques to filter your water.

Don’t get me wrong, carbon still plays the most important part in this type of filter. The additional technique staying corporate help to improve what they can do. The basic still remain in terms of the greater the amount of Carbon that is available in the filter, the better the results.

Under Sink Water Filter Buying Guide

Let’s break down the list of benefits that an under sink water filter can provide.

Sediment reduction

Sediment reduction or removal from your water is essential. Parts of the under sink system focus on this particular task. The built-in car filters helping sediment removal. Many of these systems use polypropylene to help reduce sediment.

Chlorine removal

This is one of the primary functions of the carbon filter in this type of equipment. Chlorine is totally removed from the water source. Many of the options available on the market use a special II carbon filter that is specifically tasked with removing chemicals such as chlorine.

Taste and smell improvements

Again the carbon filters in this type of system are excellent at removing poor taste and unwanted odours from your water source. This could be either a combination of filters or one specific carbon filter that performs this task.

Metal removal

There are a few options available for removal of heavy metals. Kinetic degradation fluxion and activated carbon filter are one option. KDF helps the carbon filters last longer and also increases efficiency.

You can also find the option of treated carbon filters that are just as effective at removing heavy metals but may not last as long or be as efficient.

Bacteria removal

Under sink filters usually remove all bacteria from your source. It is then by using a special cartridge inside the filter. Common bacteria that can be prevented include cryptosporidium.

Fluoride reduction

Often you will find Alumina filters within an under sink system. This type of filter is good at removing fluoride, so often so will remain.

Arsenic removal

If Arsenic is present in your water then it will also be removed using the Alumina cartridge.

Limescale reduction

Parts of the water filters cartridge are designed to specifically remove magnesium and calcium from your water source. This is an excellent option if you suffer from limescale build up from hard water in your area.

Nitrate and nitrite removal

This type of system can remove these contaminants from your water that can be particularly damaging to the young or the very old. Often these filters use Anion to remove this from your water.

How These Undersink Water Filters Work

Let’s take a look at how exactly under sink water filters work and how they can possibly fit into your home.

The first thing to understand is that there are two main types of under sink water filter. These two types of filter are-

1) Conventional under-sink water filter

Conventional under sink filters were the first type of system available on the market. This type of filter usually uses a separate faucet to deliver your filtered water. Your existing faucet or faucets will remain the same and do not come directly into the system.

This is traditionally the most simple method. An offshoot is taken from your main cold water feed into a new pipe or tube. This pipe feeds directly into the water filter, which then once filtered is sent to the newly mounted faucet.

This type of system is constantly pressurized.

The primary downside to using this type of system is that you need somewhere to locate your new faucet. You may need to this especially adapt your current set up or even buy a new sink to locate the new faucet.

Your flow rate can also be reduced due to the additional faucet.

The upsides to this type of system include generally your filters will last a lot longer has only a Small Part of the water is filtered out.

As you have a lower flow rate then the water itself will remain longer in the filter. This means the quality of the water coming out is better and the amount of filtration is greater.

This system is fairly simple to install compared to our second option.

2) Simple Under Sink Water Filter

This type of system maybe called simple, they’re actually it is quite complicated in how it works.

The system is called simple be due to how easy it is to install as opposed to the way that the system works.

The simple filter divert all the cold water feed directly through the filters. Unlike the conventional system this does not use a separate faucet for delivering the water. Water arrives through your regular existing sink setup. There is no option to filter your warm water tap.

The primary benefit of using this type of system is that it is much less bothersome do you use the existing faucets available on your sink. In terms of how everything looks and also functionality.

This type of undersink filter is usually very inexpensive to buy. You don’t need to introduce an extra faucet to your sink, so modifications tp how your faucets look are not made. This is also a very simple System to install, where you just connect up the system directly to your existing pipes.

The main downside to this type of filter is that the filters need changing more often. This is due to the sheer amount of water going through the system, all cold water goes through.

Due to the higher flow rate than this has an increased chance of contaminants passing through the filter. So the water may not be as good quality as a conventional under sink water filter.

What should we be looking for in our perfect undersink filter?

The majority of Us all require the same thing from a water filter – that’s to produce high quality filtered water. It’s not quite that simple though.

Water filters vary from one manufacturer to another. They all have their own pros and cons. There are some important aspects you should consider before you purchase your own under sink system.

Capacity of the filter

It’s important to have a high capacity filter for your water source in order to provide you with enough water throughout the day.

Depending on the makeup of your water filter, you will find that efficiency will vary from one model to another. Also, some filters will be better at removing one contaminate. Whilst another filter will be better at removing a completely different contaminate.

This will directly affect the capacity of your filter to produce good quality water.

You should also consider that he certain system maybe able to handle a very large capacity, whilst it is lacking in removing a specifically unwanted compound.

Therefore is very important to test the water prior to buying your filter. This way you’ll be able to tell which features you can do without whilst maintaining the high capacity water filter.

Pressure of your water

Water pressure is an important aspect to consider when it comes to filtering systems.

If you have a very low pressure coming through your system then it can take in each just to fill a glass full of water.

Just consider if you don’t already have good water pressure coming through your faucets, then this is only going to get worse when you had a water filter to the system.

Simple under sink water filters provide a much better pressure than a conventional system. As we discussed earlier this is a trade off though, as the water provided is not as well filtered as the conventional filter.

Again it’s important to test the water to see how contaminated it is and what contaminates it contains in it. This way you can then decide whether it is risky to use a simple under sink water filter.

Cartridge Lifespan

The majority of today’s under sink filters require filter change at approximately every 6 months. You can find systems that have much longer life spans for the cartridges. These can range as long as 5 years.

It’s no use having a cartridge that supposedly lasts five years if it loses efficiency. Surprisingly this is not always the case. The reason these long lifespan cartridges last for long is that the components they are made from are extremely high quality.

The time within which a cartridge will last will greatly be affected by the type of water you have in your local area. So it’s important especially for the first couple of filters that you test the water quality at set times through the year. This way you’ll be able to tell if the performance of your filter is being maintained or if it is falling.

You will then be able to get a clear idea of how long your cartridge plus and when you need to regularly replace it.

It’s important to know that most water filters test their capabilities at the source of your local area water provider. As you know the quality of your water changes dramatically from the time it leaves the facility until it reaches your faucet. So the time span that they announce for their filters will reduce significantly based on the quality of water in your faucet.

How Often Should I Replace The Water Filter Cartridge?

There’s no set in stone rule for how often you should change your water filter cartridge. Each and every system differs. It may be that your filter will last 3 or 4 years without a change where is other systems may need to change every 5 to 6 months.

Check the manufacturers guidance notes on when you should be changing your filter, you can even find some systems that give you an automatic update when your filter needs changing.

Cartridge cleaning and replacement

Again this process differs depending on your system and manufacturer. There are however certain steps which every filter needs to follow when you are doing a replacement or clean up. These include:

Turning off your water feed

Drain down your filter by running the Faucet dry

Open up the system so that you can get access to the cartridge

Take out the cartridge

Give the equipment a good clean and remove any unwanted debris

Replace the cartridge with a new one in the system

Close the system

Turn back on your water feed, take particular care to notice any and wanted leaks.

If you have a number of filters within the one system then it’s best to make changes to all of them at the same time, regardless of how good or poor the filters look.


We hope that you found our under sink water filter reviews and buying guide a help. The equipment covered in this guide is comprehensive and features all the latest model updates.

In future be sure to check back as we regularly update this guide with the latest water filters. We also re-evaluate our comparison chart so that you can see which would be the best option for you.

It’s important to consider all the variables when choosing the best under sink water filter as you will need to choose a model that suits your own environment and the type of water that you can be have.

Regardless of where you get your water from there is sure to be a water filter system that suits your purpose.

Do you still not know how undersink filters work? Have you skipped the buying guide? Then it’s important that you read back over the complete buying guide. As this will give you a clear idea of how they work and which type of filter will be best suited to you.

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