The best osmosis plants in the UK 2023

Only 5% of English people drink filtered tap water, even though it is the best way to enjoy pure water at home. You won't have to buy packs of bottled water and you will also contribute to reduce pollution. There are currently many water filtration systems or osmosis systems on the market. So which one should you choose? This guide will help you make the right decision.


Best value for money


The best osmosis machine in 2021

Very well known, the AEG AEGRO is highly appreciated for its performance and efficiency. It is indeed a filtration system by reverse osmosis which allows to have pure water at disposal.

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The AEG AEGRO has a powerful filtration membrane. This membrane ensures the retention of pollutants in the water. Its greatest advantage lies in its ability to effectively remove heavy metals such as lead as well as nitrates and all drug residues. Even the taste of chlorine will no longer be felt.

Whether you are preparing a hot or cold drink, you will notice the difference instantly. Measuring only 33 x 27.9 x 33.4 cm, the AEG AEGRO is one of the smallest osmosis units. It can be easily placed under the sink. Its water treatment capacity is up to 1.5 L/min. Moreover, it is quite easy to replace its 3 filter cartridges.

Osmotech Hobby ROH050 2

Best value for money

Osmotech Hobby ROH050

The best entry-level osmosis machine

Are you looking for an osmosis plant that can treat a large quantity of water at a low cost? Here is the Osmotech Profi 380. Offered at a low price, this model can provide up to 380 L of water per day.

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No matter if the water coming out of your taps is rich in heavy metals, drug residues, pesticides or asbestos, the Osmotech Profi 380 guarantees you 100% drinkable water. This 3-stage reverse osmosis plant shines by its compactness. It comes with filters and all the necessary accessories for installation.

On the first level, there is a 5 micron sediment filter. Then, on the second level, it is carbon that ensures the filtering. Finally, on the third and last level, there is a TFC membrane filter. With this level of filtration, you can have pure water up to 380 L/day.

Smardy Blue R100 3

Best value for money

Smardy Blue R100

The best high-end osmosis machine

The Smardy Blue R100 RO works independently. Just place it on a flat surface and it's ready to use. This tabletop reverse osmosis unit requires no hoses or connections.

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Besides the usual cold filtered water, the Smardy Blue R100 also provides you with hot water. This is what makes it different from the other models in this comparison. You will get the hot osmosis water at the touch of a button. The device offers 4 temperatures to choose from: normal, boiling, for tea or for baby food.

The Smart Touch control panel of the Smardy Blue R100 features a child safety system. It also informs you when it is time to change the water and filter. The QuickChange system ensures quick filter replacement.

ATH Genius Compact 4

A great choice

ATH Genius Compact

An example of practicality

The ATH Genius Compact comes with a pump and a case. Being a standard equipment, this model has a very good quality/price ratio. You can easily install it under the sink.

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The ATH Genius Compact is one of the easiest to install due to its compact design. The entire mechanism for obtaining purified and filtered water is located inside the housing. Models with a pump are highly recommended when the network pressure does not exceed 2.5 bars. On the other hand, a pump osmosis plant can reduce the flow of water discharged.

The ATH Genius Compact osmosis plant filters water in 5 stages. Thanks to its filtration system, sediments as well as suspended particles are efficiently removed. The reverse osmosis membrane optimally removes salt, heavy metals, bacteria and viruses. In addition, the device is equipped with an 8 L storage tank.

Buying guide • November 2023

Best osmosis unit

Any specific needs?

The best osmosis machine in 2021

The best entry-level osmosis machine

The best high-end osmosis machine

An example of practicality

Your guide : Samuel

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Comparison table of the best osmosis plants

Osmotech Hobby ROH050 6
Smardy Blue R100 7
ATH Genius Compact 8
Osmotech Hobby ROH050
Smardy Blue R100
ATH Genius Compact
Very well known, the AEG AEGRO is highly appreciated for its performance and efficiency. It is indeed a filtration system by reverse osmosis which allows to have pure water at disposal.
Are you looking for an osmosis plant that can treat a large quantity of water at a low cost? Here is the Osmotech Profi 380. Offered at a low price, this model can provide up to 380 L of water per day.
The Smardy Blue R100 RO works independently. Just place it on a flat surface and it's ready to use. This tabletop reverse osmosis unit requires no hoses or connections.
The ATH Genius Compact comes with a pump and a case. Being a standard equipment, this model has a very good quality/price ratio. You can easily install it under the sink.
Filtration levels
3 steps
3 steps
5 steps
5 steps
Maximum daily capacity L/day
500 L/day
380 L/day
110 L/day
33 x 27.9 x 33.4 cm
36 x 16 x 15 cm
37.5 x 24.5 x 39.5 cm
84 x 57 x 30 cm
6.4 kg
2.84 kg
14 kg
12.5 kg
Under sink
Under the sink
Over the sink
Under sink

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Buying guide - osmosis unit

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How to choose your osmosis unit

In order for a reverse osmosis unit to do its job and purify your water by intervening directly on the sink pipe, you must choose it according to a few criteria.

#1 - Dimensions of the osmosis plant

In principle, a reverse osmosis unit should be placed under the sink: this will undoubtedly facilitate its installation, handling and use. Also, make sure that the model you choose has dimensions compatible with the space under your sink. In the end, opt for a model with extensions so you can install it in a corner in your kitchen.

#2 - The performance

The efficiency of the osmosis machine is measured by the rate of purification of the water after treatment. Depending on the machine, it removes between 80 and 99% of the polluting agents and solid substances contained in tap water. Note that a good filtration quality must be above 90% and it is imperative that the machine succeeds in filtering at least the sediments greater than 5 microns.

#3 - Processing capacity

It will be necessary to refer to the capacity of the tank that accompanies the osmosis machine. This ranges from 1.5 liters up to 10 liters depending on the dimensions of the device. If you have a lot of people at home, opt for osmosis machines with large tanks, as this means that they are capable of treating several hundred liters of water in a day.

#4 - The filtration system

Any osmosis machine must be equipped with several types of filters to purify the water properly. An entry-level model will have at least 3: the sediment filter, the carbon filter and the membrane filter. The most elaborate osmosis machines will contain more and thus display better performance.

#5 - Additional options

Osmosis machine manufacturers seek to differentiate themselves by adding additional options and very practical features. Thus, you will find osmosis machines with touch-sensitive LED screens for easy operation, others that incorporate a system that allows you to heat the water and get boiling water at the tap.

How to use an osmosis machine?

A very practical device, the osmosis machine allows to purify water thanks to a triple filtration system, a membrane and the play of pressure. Generally, such a device can eliminate more than 98% of its impurities. In fact, it filters the water to eliminate unwanted minerals. It is composed of a pre-filtration zone, a reverse osmosis membrane and a post-filtration zone. The goal is to bring filtered water to the tap.

A triple filtration system because the osmosis unit works in a few steps to purify the water to this high level. Indeed, a pre-filter will retain suspended particles larger than 5µm. Then, there is a second filter with activated carbon granules which absorbs most of the chemical elements present in the water such as pesticides and other phytosanitary residues, chlorine, nitrates, bacteria, radioactive gases, etc.

Then, the elimination is followed by a third filter with activated carbon block. The latter will rid the water of micro-organisms and especially chlorine, which is very harmful to the filtration membrane of the osmosis unit. The water is then removed from the minerals and large molecules, then pressurized to pass through an ultra fine filtering membrane. This membrane removes 98% of the impurities still present.

Once this is done, the water is stored in a pressurized tank, it passes through a post-filter or a carbon finishing cartridge to remove any odor. At this point, the water delivered is generally referred to as "pure" water.

It should be noted that a high pressure of more than 3.5 bars is required for the water to pass through the membrane. Finally, in order to prolong the life of your reverse osmosis unit, you should regularly change the membranes and cartridges. Also remember to never leave the cartridges dry.

The different types of osmosis plants

To choose a reverse osmosis unit, you need to know which type best suits your sink. A wrong choice could cost you a lot of money, because the osmosis unit is not an affordable device

Under-sink Osmosis

The under-sink osmosis unit is quite complex both in terms of operation and installation. It is located between the water inlet and the faucet. You can do it yourself or have it installed by a professional. With this system, you don't have to worry about the efficiency of your RO. It treats your water faster. It has a reservoir allowing you to benefit from pure water at any time. This stock is treated well before consumption. This has the advantage of controlling the water flow.

Sink Osmosis

Some devices are intended to be installed directly on the sink. Here, installation is easier and faster. There is no need to seek help from a specialist. This reduces the cost of the investment. The filters are mounted on the wall and then connected directly to the faucet. Before leaving the tap, the water first passes through the filters of the osmosis unit to be cleaned of any impurities.

Beware, the decor of your kitchen may be impacted by the addition of this rather unsightly device. As it does not have a waste water tank, you have to improvise. Either you install one, or the drain pipe goes directly into the sink. Also, the water flow will be reduced, because the sink osmosis unit cannot treat the water used in advance.

Osmosis or water softener?

Osmosis machine

To drink tap water with peace of mind, the osmosis unit is an excellent way to filter out unwanted residues from your drinking water. The basic unit of an osmosis unit consists of a sediment filter, an activated carbon filter and a fine membrane.

Easy to install, it is effective in obtaining pure water. In addition, it is an environmentally friendly system, as it operates without electricity. Unfortunately, the osmosis system cannot treat water with a high level of limescale. Furthermore, it cannot remove the types of gases dissolved in the water.

Water softener

A water softener is a practical device for reducing the level of limescale in tap water. You will need one in some regions of France! Composed of a resin that traps calcium or magnesium ions and releases sodium. This device focuses solely on the hardness of the water and is an effective and efficient treatment.

The advantages of using it include lowering your energy bill because there is little scaling in your pipes and your water heater does not have to work as hard. The downside is that softened water is not suitable for cooking or drinking, as it can cause serious health problems for those sensitive to salt.


Whether it's a water softener or an osmosis unit, both are very practical tools. Choose the osmosis unit if you plan to purify your tap water before drinking it. The softener is much more suitable for reducing the level of limescale in your water to ensure the longevity of your household appliances.

Why buy a reverse osmosis system?

To have quality water

By equipping your kitchen with a reverse osmosis system, you can be sure to get clean water. It works on the basis of reverse osmosis developed by NASA. Its integrated filtration system guarantees light, pleasant-tasting and very clear water. It is very popular because of its triple filtration system that purifies the water so that it is drinkable as soon as it comes out of the tap. It eliminates all kinds of impurities such as metal bits and chlorine. A fine membrane also filters out mercury, which can cause many diseases, including cancer.

To stay healthy

This device removes about 98% of any harmful elements that may be present. Traces of pesticides, nitrates, bacteria and drug residues are all eliminated through its three-fold filtration. Thus, osmosis water is beneficial for your health, but also for your skin.

To save money

The osmosis system also has an economic advantage. It saves you from having to buy bottled drinking water. In the long run, you will certainly save a lot of money with the purchase of this device.

To preserve the environment

The use of a reverse osmosis system also has an ecological side. Since you will no longer have to pay for bottled drinking water, you will no longer have to throw plastics into the environment. Your ecological footprint is thus limited.

To have permanently filtered water

An osmosis system is installed at your kitchen faucet. You benefit directly from quality water to drink every day. You can also use it to prepare your meals or wash your kitchen utensils. Supplying your appliances with pure water optimizes their performance and longevity. In addition, the osmosis system filters seawater to reduce salt content and bacteria.

The best brands of osmosis plants

In our opinion, the best brands of osmosis plants in 2022 are :


AEG is a brand that was founded more than a century ago on a simple philosophy: everything it designs must be perfect in terms of both aesthetics and function. The company was founded in 1883 and is best known for its household appliances. But its aegro osmosis machine is also highly acclaimed for its performance.

Osmotech is a brand of Kurita Water Industries, a company listed on the Frankfurt Stock Exchange. It is a brand that has an excellent reputation in the home water filtration market. It offers rather entry-level to mid-range products, ideal for small budgets.

Amtra is a company that has been around for 25 years now. It was first known for its products for the aquarium industry (aquariums, aquarium filtration systems, etc.), but now it also offers filtration systems for domestic use. The "System 190" osmosis system, for example, treats tap water in three filtration stages to obtain very soft water.

Dennerle is a German company founded in 1966. Initially specialising in aquariums, the company has gradually expanded its activities. Today, it offers reliable and efficient filtration systems for the whole house.

Water2Buy is an Irish company that has made a name for itself with its do-it-yourself reverse osmosis systems, sold online. The company set up its website in 2006 with the aim of being "Europe's leading online water treatment provider". It became a fully-fledged brand in 2009. Today the company offers some of the cheapest and most affordable water softeners on the European market.

What is the price for an osmosis unit

The diagram below will help you to get an idea of the typical prices for each price range (entry-level, mid-range and high-end).

However, more expensive does not necessarily mean better.

We therefore advise you to always consult our ranking before deciding, rather than blindly relying on price ranges.

70 £ to 150 £
150 £ to 300 £
more than 300 £
Price range diagram


Prepare all tools before installation.

Check the installation guide to see what tools you will need. You will probably need a drill and wrenches. Plumbing tape and spare washers can also be useful, so try to keep some on hand.

Test the pH of your water.


the pH of the water between your osmosis system and the regular tap with a pH test. Check the pH or even mineral levels regularly to monitor the effectiveness of your system.

Establish a maintenance schedule.


osmosis system needs regular cleaning and maintenance, as explained in their user guides. Create a calendar on your phone or schedule dates on your calendar to remind you when you should clean your unit.

Clear the space under your sink.

Oosmosis units usually take up a reasonable amount of space, so you can eliminate unnecessary items. This is also a good opportunity to get rid of unused utensils, excess boxes and cartons. It's also an opportunity to give the space a deep clean or a new application of closet liner.

Sanitize the storage tank.


time you change the system membrane, be sure to disinfect the tank. After a while, all tanks become slimy. Run a disinfectant solution through the system every couple of years to get rid of the dirt that has accumulated over the years.


Note: Below are some of the sources we have consulted in writing this article. Links to other sites are not continuously updated. It is therefore possible that a link may not be found. Please use a search engine to find the desired information.
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March 2022 : Translation of this buying guide from our partner

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Our selection
Osmotech Hobby ROH050 10
Osmotech Hobby ROH050
Smardy Blue R100 11
Smardy Blue R100
ATH Genius Compact 12
ATH Genius Compact


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