Reverse osmosis – what is that? Put most simply, this is a process which purifies your water – typically used for house water, but can also be used on an industrial scale

Pretty easy to understand, but harder for the layman to know which of these are the best reverse osmosis systems available. For instance, how does it work and why would you need it? Well, if you live in a large city or newly developed area, you’ll especially want to consider this approach to cleaning your water.

For this review, we’ve chosen ten of the top models available, based on their number of filtration stages, the gallons which can cycle through them per day, the size and ease of installment, and the overall reduction of contaminants. Additionally, this research provides advice to distinguish between the best reverse osmosis system for you, and the rest on the market.

Our research comprises direct questions to the manufacturers, opinions from reviewers about what they liked and what they didn’t, as well as an analysis of product specs and test results. To make it more accessible and easier to understand, the products are organized in tables highlighting their features, detailed descriptions, and pros or cons. This table is followed by a buying guide to help you best make your purchase; it’s our goal to make it very easy for you to pick the best reverse osmosis system on the market.

Quick Summary

Editor's Choice:
iSpring RCC7AK

"A 7 stage system which can be used to filter all water in your house – from bathroom to kitchen."

Best for Home:
Home Master TMAFC-ERP

"Does not only remove all the minerals from your water, but also reintroduces good ones without extra water waste."

Best Extras:
Geekpure RO5

"Good-looking European-design faucet will add a sophisticated look to your kitchen together with premium-quality water."

Budget Pick:
Express Water RO5DX

"Affordable system that provides you with fresh and clear water every day."

Best Mineral Taste:

"Leak-free system that hardly makes any noise and can be installed practically anywhere."

Best GPD:
APEC Water Systems Ultimate RO-90

"Economical in a long run, this is an ideal pick for those searching for good pressure and speed."

Small Family Pick:
Olympia Water Systems OROS-50

"Easy-to-install system that doesn’t require too frequent filter replacement."

Longest Lasting Filters:
iSpring RCC7

"Comprehensive instructions will help you install it with ease to enjoy the best water quality on the same day."

Largest Tank Size:
APEC Water Systems ESSENCE ROES-50

"The extra-large tank makes it easier to use huge amount of water all at once without waiting for it to get filtered."

Small Kitchen Pick:
Global Water RO-505

"Affordable and compact – nice pick for a small house."

Top 10 Reverse Osmosis Systems Review 2021


iSpring RCC7AK – Editor's Choice


Number of stages: 6

Dimensions: 14.5 x 5.2 x 18.5 inches

Contaminant reduction: lead, chlorine, fluoride, arsenic, hormones, asbestos, calcium, sodium, bacteria, giardia, viruses and more

Flow rate (GPD): 75

Warranty: 3-year limited

Certification: WQA Gold Seal certification

More features: additional Alkaline Remineralization (AK) stage

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This is by far the best example of a point of use filter available on the market. It mounts below the sink with moderate assembly, and then works to remove up to 99% of all water contaminants (that’s over 1000 particles from your hard water). With lead specifically (higher amounts leading to lead poisoning) this high-end filtration system removes up to 98% every time. Additionally, this can be stalled at the point of entry to your refrigerator or even your shower, guaranteeing crystal clear ice cubes for your drink or softer water as you get clean. Best of all you don’t have to worry about the first five stages through the RO membrane removing helpful minerals because the sixth stage of purification – an alkaline remineralization filter – restores all these healthy minerals to your water.

Typical assembly can take up to an hour, but the instructions are professionally lined out and easy to follow; the manufacturers also are on call for any questions or advice. This will fit under any standard kitchen sink, and it’s guaranteed to make your water taste better, feel softer, and be healthier.

Why are we impressed?

Filtration system re-mineralizes your water with good minerals

Six stages of purification

Leak-free installation

Clear good-tasting water

Comes with a gorgeous European-design faucet

Water waste ratio is 1:2

What negatives must you be aware of?

Some filters will need replacing once, sometimes twice a year

High price

Manufacturer does not sell replacement filters


Home Master TMAFC-ERP – Best for Home


Number of stages: 7

Dimensions: 12 x 16 x 20 inches

Contaminant reduction:  chloramines, chlorine, chemicals, heavy metals, dissolved solids, pharmaceuticals, and others

Flow rate (GPD): 75

Warranty: 5-year limited

Certification: NSF certified

More features: adds calcium and magnesium minerals twice during the purification process

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This can be used as both a POU system or a POE system, meaning that the tank is large enough and the membranes are strong enough to attach at the location where water enters your house and filters all water – for your kitchen sink, bathrooms, and refrigerator. It also comes with the largest number of purifying stages, the first 5 stages which remove all chemicals, bacteria, and hard water materials. Stages 6 and 7 use patented full contact technology to reintroduce good minerals for added taste and necessary health, including additions of calcium and magnesium minerals which you need in a regular diet. Additionally, a built-in non-electronic pump can be purchased which will reduce the systems water waste by 80%. The filters are long-lasting, easy-to-change, and require no wrenches or other tools.

What makes it stand out?

POE system for a full house

7-stage system which reintroduces good minerals

Additional pump will reduce water waste ratio; 1:1.5

Can also be attached under a sink

5-year warranty

Which disadvantages must you keep in mind?

Without the purchase of a pump, water waste ratio is 1:4

Heavy installation required

Most expensive unit on this list

Does not come with extra replacement filters


Geekpure RO5 – Best Extras


Number of stages: 5

Dimensions: 14.2 x 6.2 x 18.1 inches

Contaminant reduction: heavy metal, arsenic, lead, mercury, fluoride, and more 1000+ contaminants

Flow rate (GPD): 75

Warranty: 1-year limited

Certification: all tube, fittings, storage tank, RO membrane complies with NSF/ANSI standard

More features: 7 replacement filters

Check price


This NSF and ANSI rated system is designed to efficiently filter your water in five stages, first getting rid of any fibers, dust, colours, and odors. In the final stages of purification, it removes up to 99% of all contaminates in your water, extracting all heavy metals, chemicals, and bacteria. Unlike six stage RO systems which reintroduce good minerals, this system does not, but it does come with a 1-year warranty and seven extra replacement filters. Replacement filters are normally quite expensive and the cost can slowly add up, but with seven extra you don’t need to buy filters for at least 2-3 years of use. Included in your purchase is a European-made 100% lead-free faucet, and the added instructions for the entire system should make installation quite easy. In no time at all you’ll be drinking healthier, crystal clear water. Whether you get your water from the city, a well, or the local reservoir, this filtration system will do a fine job keeping your water safe from pollutants.

What are our favorite features?

BPA free materials

Easy mounted installation for under the kitchen sink

7 replacement filters are included

Water waste ration is 1:2

Comes with a European-made 100% lead-free faucet

Amazing market price

What could be better?

Does not reintroduce good minerals back into water

Product inhibits some water pressure, but does come with a water-pump option

T-connector must be purchased separately to connect refrigerator


Express Water RO5DX – Budget Pick


Number of stages: 5

Dimensions: 16.2 x 18.8 x 18.1 inches

Contaminant reduction: lead, arsenic, chromium, fluoride, TDS, radium and others

Flow rate (GPD): 50

Warranty: 1-year limited

Certification: not specified

More features: fast flow faucet with 0.8 GPM delivery

Check price


This system will filter your water until the tank is full, rather than working every time you turn the tap, and therefore you’ll have a full tank of crystal clear water every time you need it – refills automatically without having to be reset. It comes with 5 stages of purification and the filters are coconut carbon, giving your water a natural taste. In case of any leakage, the system comes with a detector that shuts down water purification if any unwanted moisture gets out. The reason this is our budget pick is that it not only removes hard components from all your water, but it also comes at the best price for such high quality.

Why is it special?

Comes with 4 replacement filters

Easy installation

Early stages make the later membranes (stage 4-5) last longer

RO filters only need swapping once a year

Does not slow water flow

Water waste ratio is 1:2

What are the flaws?

Pre-filters will need swapping twice a year

Water is not on-demand, but rather fills your tank to maximum capacity


10 Best Under Sink Water Filters – Crisp and Clean Drinking Water, Straight From Your Tap!


APEC Water Systems ESSENCE ROES-PH75 – Best Mineral Taste


Number of stages: 6

Dimensions: 16 x 5.2 x 17.5 inches

Contaminant reduction: arsenic, lead, fluoride, chromium, radium, bacteria, viruses and more

Flow rate (GPD): 75

Warranty: 1-year limited

Certification: FDA Certified JG Food grade tubing and parts

More features: 100% lead-free designer faucet

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Another great six stage filtration system. It not only removes up to 99% of negative solids from your water but it also adds in calcium minerals to improve the taste of your soft water. For those who love mineral water, this system reintroduces good minerals in its sixth stage as well as that calcium taste; bottle your water right at home and save money. During the first stage a high-capacity polypropylene filter removes rust, particles, and dust. The next three stages eliminate chemicals, odors, cloudiness, and other unhealthy solids. These solids can be anything from deadly arsenics and leads, to bacteria and viruses. Once its done with all its stages, including the sixth one which revitalizes with water, you won’t be disappointed by what comes out of the tap: pure, good tasting, healthy water every time.

What do we love it for?

Noise-free system, which can be installed POU under your kitchen sink or where water comes into your shower

Has extra lock seal clips for the tank, making it leak-free

Comes with a 100% lead-free faucet

What were we disappointed with?

Extensive assembly

Rather expensive

Water waste ratio is 1:3

Doesn’t filter as well without good water pressure


10 Best Under Sink Water Filters – Crisp and Clean Drinking Water, Straight From Your Tap!


APEC Water Systems Ultimate RO-90 – Best GPD


Number of stages: 5

Dimensions: 16 x 5.2 x 17.5 inches

Contaminant reduction: arsenic, chlorine, lead, fluoride, heavy metals, bacteria, virus and 1000+ contaminants

Flow rate (GPD): 90

Warranty: 1-year limited

Certification: WQA Gold Seal certification, NSF certified filters

More features:  free from water leaks, bursts and noises

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Providing water tasting far more superior to bottled water, not only is it healthier for you, but it also saves your money in the long run on bottled water throughout a year. This top tier brand is designed with 5 contaminate-removing stages that are NSF certified and will remove up to 99% of all hard pollutants. This system is ideal for cities where tap water is full of chlorine, heavy leads, too much fluoride, bacteria, and other viruses. As an added bonus, its filters are certified to last twice as long as other brands, meaning less money spent on replacing them and more extended use of your reverse osmosis system. Very comprehensive installation manual makes it easy to install so that you can do by yourself right at home. One moment – unhealthy city water, the next – you’re sipping fresh crystal-clear water.

What stands out?

Both FDA and NSF certified

Tank can be laid flat for smaller under-sink cabinets

Great pressure and water flow

Filter replacement every year or two, depending on use

What cons did we manage to find?

Long installation process, but comes with comprehensive instructions

Water waste ratio is 1:3

Supplied faucet must be used for system to work properly

Does not replace valuable minerals back in water


Olympia Water Systems OROS-50 – Small Family Pick


Number of stages: 5

Dimensions: 16.5 x 16.5 x 19.7 inches

Contaminant reduction: arsenic, fluoride, barium, lead, cadmium and more

Flow rate (GPD): 50

Warranty: 1-year limited

Certification: NSF certified

More features:   quick connect fittings caps for easy installation

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This product from iSpring uses its first three filtration stages to do away with sediment, rust, pesticide, chlorine, you name it! This POU reverse osmosis system is made to fit in most under-sink cabinets, but can also be installed in a recess of the wall where water enters toward the kitchen, or bathroom if you want to use it for baths and showers. Equipped with a high capacity polypropylene sediment filter, this product filters all hard water down to 5 microns (that’s nearly 96% filtration). These first three stages of filtration also have strong enough membranes that they don’t need replacing till at least the end of their first year being used or longer. Perfect for a family of 4 (or more depending on your water usage), the filters have the capacity to clean 100,000 gallons of water for one full year of pure water.

What makes it special?

Very good price for such a professional system

Five stages of filtration

Can supply you with up to 50 gallons of pure water a day

Moderate assembly required.

Very minimum impact on water pressure and water flow

Filters only need changing every 4-5 years

What cons did we find?

Waste ratio is 1 pure gallon for every 4 gallons of water waste

Doesn’t filter as well without good water pressure

Removes fluoride from city tap water

Larger system than most and might be a tight squeeze in a cramped under-sink cabinet


iSpring RCC7 – Longest Lasting Filters


Number of stages: 5

Dimensions: 14.5 x 5.2 x 17.5 inches

Contaminant reduction: lead, chlorine, fluoride, arsenic, hormones, asbestos, calcium, sodium, bacteria, giardia, viruses and more

Flow rate (GPD): 75

Warranty: 1-year limited

Certification: WQA Gold Seal certified

More features: comes with nickel all-metal faucet and clear see-through 1st stage housing

Check price


This mountable system can fit quite snuggly in a utility room – connected to pipes for your shower or bath – or in your under-sink cabinet in the kitchen. With a five-stage purification system, this takes your unfiltered water and removes the lead, chlorine, arsenic, calcium, giardia, and other hard water pollutants. It has a 99% rate of removal (that’s over 1000 contaminants), so that you can experience clean, safe, and good-tasting water every time you turn on the faucet. A trustworthy brand, this system has been certified by the NSF, ANSI, and the WQA (Water Quality Association). Rated among the best under sink water filters, it will fit under a standard sink, is leak-free, and comes with a brushed nickel all-metal faucet.

What are its best features?

Certified by NSF, ANSI, and WQA

Easy installation with comprehensive instructions and videos

Filters need only be changed every year to two years

Comes with European-designed faucet

What could be improved?

Water waste ration is 1:5

Takes 2 hours to initially fill tank

Removes fluoride from water

Does not reintroduce good minerals back to the water


10 Best Under Sink Water Filters – Crisp and Clean Drinking Water, Straight From Your Tap!


APEC Water Systems ESSENCE ROES-50 – Largest Tank Size


Number of stages: 5

Dimensions: 16 x 5.2 x 17.5 inches

Contaminant reduction: chlorine, taste, odor, toxic fluoride, arsenic, lead, and chromium.

Flow rate (GPM): 50

Warranty: 1-year limited

Certification: FDA Certified JG Food grade tubing

More features: 100% lead-free designer faucet

Check price


Another POU connecting system, this was built with supreme quality and moreover, it comes with a 2-year warranty. The system includes all the parts for a five-stage filtration process, removing 99% of contaminants from hard water entering your house. Its easy installation comes with instructions and even videos so that you can insert it under an average kitchen sink, or even mount it for your shower and bath. The filters included are premium and long-lasting, making it so you spend less on changes and so that your system gives you clear and healthy water longer. Making this purchase ensures top of the line quality for a medium price, excellent for nicer homes in big cities.

What makes it special?

Long lasting filters; change every one to two years

FDA and NSF certified.

2-year limited warranty

Comes with a 100% lead-free faucet

Tank holds 3 gallons when full

What cons did we find?

Included faucet must be used for product to work properly

Removes added fluoride

Extra adapters are needed to hook it up anywhere other than the kitchen sink

Water waste ratio is 1:3


Global Water RO-505 – Small Kitchen Pick


Number of stages: 5

Dimensions: 14 x 5 x 16 inches

Contaminant reduction: heavy metal, salt, arsenic, chlorine, lead, fluoride, and other dissolved chemicals

Flow rate (GPD): up to 50

Warranty: 1-year limited to factory defects

Certification: NSF certified faucet and steel tank

More features: 100% lead-free parts

Check price


When there are over 1000 water pollutants in your regular tap water, it’s hard to catch them all, but this product with its 5-stage filter system actually guarantees that it will. Eliminating chlorine, iron, arsenic, sulfates and nitrates, and any other contaminants you can name, this is a high-end system for a very low price. Fittings are used to make installation easy, and technical support is always on call for any questions. Once installed, it will filter around 99% of all contaminants without changing your water pressure or limiting how much water you regularly use a day. This point of usage system is built for installation under your kitchen sink or even where the water enters the room for your bathtub, shower, and other appliances (including the refrigerator). Stages 1-3 remove all chemicals, smells, and inorganics, and the last stages eliminate all hard water minerals. What comes out of the tap is crystal clear heaven.

What makes it special?

Filters need replacement only once a year

Easy installation

Affordable price

Holds two gallons on demand before immediately purifying more

What cons did we find?

Low water pressure will inhibit full filtration

Replacement filters are not included

RO filter not included

Good minerals are not reintroduced into water

Things to Consider

If you haven’t used or even heard of a reverse osmosis system before, then you’ll probably have a lot of questions, such as when would you need one? Should you only get one for your sink, or should you get one which filtrates the whole house? In the remainder of this buying guide we provide advice on common concerns which people have about their water and how to clean it, or if they even need to clean it. We also provide advice on the type of system to buy, what dimensions will work best for your kitchen, etc.

How does a reverse osmosis system work?

The way reverse osmosis systems work is by using semipermeable membranes (picture a strainer), sometimes multiple membranes, attached at a water source to separate the dissolved inorganic solids (salts, irons, lead, pesticides, nitrates, and other) which are contaminating your water. With these removed, your purified water then tastes better and it actually becomes better for your health. These systems come with easy instructions and are generally very simple to install at point of use areas in your house. Devices are installed and can be attached where the water comes out (these are point of use systems; POU) at your sink, fridge, or even bathtub and shower. Some of these devices are specifically designed to attach at where the water enters the house by tying into your main water line, usually in the garage (these are point of entry systems; POE), and they purify the water throughout your entire household.

Do you need a reverse osmosis system for the whole house?

At first this might seem like it’s a matter of opinion, whether you want to purify all the water in the house or just the water in the kitchen. However, it’s not just the water from the kitchen or refrigerator that’s going to affect you. Our skin and hair also absorb the hard metals in bath and shower water, and if you live in an environment where the water is especially contaminated, then you might want to consider filtrating all hard water being used in your house. In the bathroom, you also brush your teeth, wash your face, and rinse, and all of these activities leave remaining chemicals and metals in your system.

If you don’t know the composition of your water (unfiltered) purchase PH strips and test it yourself. Safe water has a PH between 6 and 7.5, any higher or lower can mean that there are chemicals, irons, bacteria, and even pesticides. These elements seep in through ground water, breaks in pipes, or just don’t receive enough purification from the city. Also, in small amounts these might not be deadly, but when you use this water to wash a wound, or fill up a bottle to make baby formula, even the small particles can be dangerous to one’s health.

You might just want to consider a whole house filtration system.

Other features to consider

Not any filter will do, especially if you want to pick one that will suit your household and preferences and needs of those living in it. For instance, the number of stages in a reverse osmosis system can majorly affect the taste of your water as well as your meals. Most 6 stage systems will add good minerals back into your water, not only improving the taste but also improving the health value of the water. A great example of a 6-stage system is the iSpring RCC7AK, it’s actually very cheap for such a high caliber system and it not only purifies your water but adds the good minerals back in. Other features might also make a big difference to you and your family, such as how much water a system will waste making one clean gallon for a bath, or how often you’ll have to replace parts/clean your system, if the contamination reduction will go down over gradual usage. These are all factors which will make or break a decision to buy a whole h