10 Best Reverse Osmosis Systems to Buy in 2021 – Reviews and Buying Guide

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

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

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

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

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

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

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

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

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

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