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10 Best Reverse Osmosis Systems in 2021 — Reviews & Top Picks

glass with tap water_shutterstock_sonsart

glass with tap water_shutterstock_sonsartIf having healthy drinking water is important to you, you may want to consider investing in a reverse osmosis system. These filtration systems remove harmful particles from your water, leaving behind only pure, clean liquid.

However, deciding on which reverse osmosis system to buy can be a pain, as it seemingly takes a Ph.D. in chemistry to tell them apart. In the reviews below, we looked at the top systems on the market today to find out which systems are the best.

We broke our answers down into several categories, which should hopefully help you find the one that’s best for your particular situation. Which systems made the cut? Read on to find out.


A Quick Comparison of Our Favorites for 2021

Rating Image Product Details
Best Overall
Winner
Waterdrop WD-G3-W Waterdrop WD-G3-W
  • Sleek and attractive
  • Incredibly easy to install
  • Small footprint
  • Best Value
    Second place
    Olympia OROS-50 Olympia OROS-50
  • Great value for the price
  • Compact and easy to install
  • Instructions are easy to follow
  • Best Tankless
    Third place
    iSpring RCS5T iSpring RCS5T
  • Long filter life
  • Suitable for commercial use
  • Provides high pressure
  • Best for Drinking Water
    Brondell RC100 Brondell RC100
  • Great taste
  • Water-saving technology
  • Boasts four-stage filtration
  • Best Countertop
    RKIN OnliPure RKIN OnliPure
  • Can be kept on the counter
  • No installation required
  • Filters quickly
  • The 10 Best Reverse Osmosis Systems

    1. Waterdrop Reverse Osmosis Water Filtration System — Best Overall

    Waterdrop WD-G3-W

    It looks like a fancy computer, and the Waterdrop WD-G3-W may indeed be smarter than the desktop in your office.

    It filters water quickly, and that’s because it has a tankless design that gives you clean water on demand. That design also eliminates the chance for secondary pollution, while saving you a ton of space under your sink.

    Your water is pushed through a .0001 micrometer membrane that removes 99% of contaminants. It’s especially good at removing fluoride, chlorine, and heavy metals.

    It’s also beautiful — both the parts that guests will see and the ones they won’t. The faucet is sleek and attractive, with a glowing ring that indicates its readiness. The system itself looks like something Apple might have made.

    Best of all, it’s incredibly easy to install. It takes only a few minutes to put in, and changing the filters takes seconds.

    There’s one big drawback: the price. It’s an expensive unit, but if you’re serious about having the cleanest water possible, the Waterdrop WD-G3-W is as good as it gets.

    Pros
    • Sleek and attractive
    • .0001 micrometer membrane removes 99% of contaminants
    • Incredibly easy to install
    • Small footprint
    • Tankless design removes chances for secondary pollution
    Cons
    • On the pricey side

    2. Olympia Reverse Osmosis Water Filtration System — Best Value

    Olympia OROS-50

    If money is an issue, the Olympia OROS-50 provides clean, delicious water that belies its low price point. In fact, it’s our pick for best reverse osmosis system for the money

    It’s capable of filtering 50 gallons per day, which is impressive — especially considering the average household only uses 3 gallons or so per day. The drain refills quickly, so you shouldn’t be out of water often, if ever.

    The system is fairly compact and easy to install, although it’s easy to mess up drilling the drain hole if you’re not careful. Luckily, the instructions are clear and helpful.

    You can hook it up to the water dispenser or ice cube maker in your fridge, and not only will the resulting liquid taste better, but it will also look clearer.

    It struggles a bit with well water, so it may not be ideal for rural users. City users should be perfectly fine, though.

    The Olympia OROS-50 isn’t just the best cheap reverse osmosis system you can buy — it’s also one of the best you can buy, period.

    Pros
    • Great value for the price
    • Can filter up to 50 gallons a day
    • Compact and easy to install
    • Instructions are easy to follow
    • Works well when hooked up to fridge
    Cons
    • Not ideal for well water
    • Easy to screw up drilling drain hole

    3. iSpring RCS5T Reverse Osmosis Water Filter System — Best Tankless

    iSpring RCS5T

    The iSpring RCS5T is a commercial-level system that will keep your pressure high and your glasses full. It’s capable of producing a whopping 500 gallons of water per day, all while maintaining a 1:1 pure-to-drain ratio.

    It’s unlikely that the average household will need all that power, but that just means you’ll get more life out of the filters. The manufacturer estimates that you’ll only need to change them every two or three years, based on normal use.

    The pressure that this unit can produce is fantastic, even if you’re not giving it much to work with. It can be used on sources as low as 25 psi, and the built-in pressure gauge lets you know exactly how much force it’s generating at any given moment.

    Of course, you’ll have to pay for all this power, and the RCS5T certainly isn’t cheap. You’ll also need a large amount of space for it, even though it’s a tankless model, so don’t expect to keep anything else under your sink. It’s something of a beast to install.

    If you can afford it, the iSpring RCS5T will give you a ton of clean water, and it will provide that water with a generous amount of pressure.

    Pros
    • Can provide up to 500 gallons per day
    • Long filter life
    • Suitable for commercial use
    • Provides high pressure
    Cons
    • Expensive
    • Takes up a large amount of space
    • Difficult to install

    4. Brondell Circle Reverse Osmosis System — Best for Drinking Water

    Brondell RC100

    The Brondell RC100 will likely save you a bundle over the long run, as it’s built with water-saving technology. That makes it extremely efficient, as it can completely refill itself in less than an hour. It’s also environmentally friendly, as it will cut down on wasted water.

    It uses four-stage filtration to clean out your H2O, ensuring that virtually all chemicals, minerals, and foul tastes are eliminated before reaching your glass. Despite boasting all those filters, it’s compact and will leave plenty of free space underneath your sink.

    No one will see how compact it is, of course, since it’s stuck under the sink. What they will see, however, is the sleek designer faucet that comes with it. It’s understated and classy, and it has an LED indicator that lets you know when it’s time to change the filters.

    The biggest downside to this unit is the fact that the line isn’t pressurized, so it’s slower than other models. The water it produces is well worth the wait, however. You’ll also likely need to drill a hole in your countertop to install it.

    If your primary concern is the taste of your water (and you’re willing to wait for it), the Brondell RC100 is hard to beat.

    Pros
    • Great taste
    • Water-saving technology
    • Boasts four-stage filtration
    • Can completely refill in less than an hour
    Cons
    • Line isn’t pressurized
    • Requires drilling a hole into countertop

    5. RKIN OnliPure — Best Countertop

    RKIN OnliPure

    If the space under your sink is reserved for cleaning products and junk you haven’t used in ages, the RKIN OnliPure will give you delicious H20 without forcing you to clean house.

    It’s a zero-installation model, which is exactly what it sounds like. All you have to do is fill it with water from your faucet, and the machine will do the rest. Of course, that requires a bit more effort in the long run, as you’ll have to keep refilling it, but at least you won’t need to tamper with your plumbing.

    The upside is that you can put it almost anywhere. It takes up little space, and you don’t have to necessarily keep it next to the sink. Since you’re filling the reservoir on the bottom, you don’t need clearance on the top or sides, allowing you to put it under cabinets.

    It takes about 15 minutes to purify a half-gallon of water, making it suitable for most families. It’s silent while it works too.

    One issue that you may run into is the difficulty in finding replacement filters. They’re not easy to locate, so buy them in bulk when you track them down.

    The RKIN OnliPure isn’t a great choice for families that go through a large amount of water, but for everyone else, it’s a convenient and space-saving option that works just as well as the more complicated models out there.

    Pros
    • Can be kept on the counter
    • No installation required
    • Filters quickly
    • Fits in just about any space
    Cons
    • Takes more effort to fill
    • Not ideal for families that use a large amount of water

    6. APEC Reverse Osmosis Water Filter System — Best for Well Water

    APEC ROES-50-A

    Don’t let the reasonable price tag on the APEC ROES-50-A fool you: This is a serious filtration system.

    It’s fantastic for use on both tap and well water, and it can filter out over 1,000 contaminants. The result is clear, clean, odorless water.

    It’s especially good at removing chlorine, thanks to the double carbon blocks inside the filters. The blocks themselves are huge, ensuring that every bit of water will get thoroughly cleaned before it comes out the tap.

    Installation is fairly simple, but if you have any problems, you can consult their detailed guide or helpful online instructional videos. The fittings are leak-free, and there’s no need to invest in a leak detector to make sure everything is working properly.

    The thing does leave quite a bit of air in the water, so expect sputtering every time you turn it on. It also wastes a good amount of water, which will offset the up-front savings somewhat.

    Those aren’t enough for us to penalize the APEC ROES-50-A too terribly much, and it’s a great choice for homeowners on a budget.

    Pros
    • Reasonable price tag
    • Works on both tap and well water
    • Filters out over 1,000 contaminants
    • Easy to install
    • Excellent at removing chlorine
    Cons
    • Wastes a fair amount of water
    • Leave air in the line

    7. iSpring RCC7AK Reverse Osmosis Water Filter System — Best for Alkaline Water

    iSpring RCC7AK

    You may not want a filter that strips every single mineral out of your drinking water. If you prefer your drinks to be alkaline, the iSpring RCC7AK is the way to go.

    The water goes through three filters before it reaches the reverse osmosis stage: a sediment filter, carbon KDF filter, and carbon block filter. This skims off most of the heavy particles, as well as chemicals like chlorine.

    The reverse osmosis filter removes anything larger than .0001 microns, so you’re left with virtually nothing but water.

    After that, this newly-purified water is fed into an alkaline remineralization filter that puts healthy minerals back into the water, restoring its alkaline balance. This also gives the water a natural taste, which some people love and others hate.

    Be aware, however, that this often gives the water a milky color, so don’t expect it to be perfectly clear. Also, it’s prone to leaking if not installed perfectly, so you may want to have a professional handle the installation.

    The iSpring RCC7AK is a fine filtration system, but what sets it apart is its ability to create alkaline water. That’s not for everyone, but it may be exactly what some people are looking for.

    Pros
    • Reintroduces healthy minerals into water
    • Excellent at removing chlorine
    • Gives water natural taste
    • Removes particles larger than .0001 microns
    Cons
    • Water has milky color
    • Will leak if not installed perfectly

    8. Home Master HydroGardener Reverse Osmosis Water Filtration System — Best Outdoor

    Home Master HydroGardener

    For those who think that better water may be the key to greening up their thumbs, the Home Master HydroGardener Pro Advanced is the best way to keep their plants alive and healthy.

    It’s especially good at filtering well water, as it can remove up to 98% of all contaminants inside. It also does well with low-pressure systems, as it works at pressures as low as 35 psi.

    That makes it excellent for hydroponics systems because it prevents heavy minerals from destroying sensitive components. It offers a 1:1 waste ratio as well, ensuring that you let the minimum amount of water escape your thirsty plants.

    The water it produces is suitable for drinking but probably won’t taste as good as the water made in some of the other systems on this list. It makes a large amount of it, though, as much as 120 gallons per day.

    Expect to have air in the line, which shouldn’t be much of an issue if you don’t mind bubbles in your water. You’ll have to put up with sputtering, though.

    Overall, the Home Master HydroGardener Pro Advanced is the best unit out there for whipping vegetation into shape, but if you’re trying to keep humans happy, you might want to go with something else.

    Pros
    • Excellent for gardens and hydroponic systems
    • Ideal for well water
    • Does a great job of removing heavy minerals
    • Produces up to 120 gallons a day
    Cons
    • Water doesn’t taste as good as that from other systems
    • Lets air into line

    9. APEC Water Systems RO-CTOP-PH — Best Portable

    APEC Water Systems RO-CTOP-PH

    If you’re on the go frequently but don’t trust the water in the hotels you stay at, the APEC Water Systems RO-CTOP-PH is a portable system that gives you clean water wherever you go.

    All you have to do is connect it directly to the faucet, and the water will run through the system and out the hose on the other end. You can do this in seconds and it works with any standard faucet.

    It’s bulky to travel with, but the aluminum casing is durable, so it can withstand a few bumps and dings. It’s not just for travelers either; it’s perfect for apartment dwellers or anyone who rents and doesn’t have the option of carving up the kitchen to install a more permanent model.

    Despite the fact that it’s easy to attach and detach, it’s capable of serious filtration. It provides four-stage filtration, and the resulting liquid is purer than anything you’ll buy in a bottle.

    You’ll have to wait to get that water, though, which can be frustrating if you’re in a hurry. It also produces a great deal of waste, which may rankle environmentally-conscious users.

    Other than that, though, there’s little to quibble about with the APEC Water Systems RO-CTOP-PH. It’s not as formidable as some permanent models, but it works just as well.

    Pros
    • Portable option
    • Attaches to any standard faucet
    • Durable aluminum casing
    • Offers four-stage filtration
    Cons
    • Bulky and cumbersome to travel with
    • Takes a long time to filter
    • Wastes water

    10. Frizzlife PD600 Reverse Osmosis Under Sink Water Filtration System — Best Under Sink

    Frizzlife PD600

    The Frizzlife PD600 just looks like it means business — and it does. It’s a shame that it has to hide under the sink, where no one will see its impressive chrome body.

    You’ll want to take a look at it every now and then, though, because it has an LED display that lets you know the lifespan of each filter, as well as the quality of your drinking water.

    It’s a tankless system, which makes it surprisingly small. You’ll have plenty of space left in the cabinet after installing this thing. Despite its small footprint, it can churn out a ton of water: 600 gallons a day, to be exact. It does so with a rapid flow too, so even the biggest families should never go thirsty.

    It adds minerals back into the water to make it alkaline and keeps the pH level above 7.5.

    The system is available with an optional leak protector; we advise skipping it, as it often causes more leaks than it stops. Also, while the company offers instructional videos to assist with installation, they’re not that helpful, so you’ll have to figure it out on your own.

    Those minor dings aside, the Frizzlife PD600 is one of the best overall systems on the market — and maybe the best under-sink model.

    Pros
    • Small footprint
    • LED display reveals quality of water
    • Produces up to 600 gallons per day
    • Rapid flow
    • Adds minerals back into water
    Cons
    • Leak protector does more harm than good
    • Installation instructions aren’t helpful

    Divider 4

    Buyer’s Guide

    Unless you’ve been studying water filtration systems for years, some of the terminology may seem confusing. Below, we’ve put together a small guide that will hopefully demystify the reverse osmosis process.

    What Is Reverse Osmosis?

    In a reverse osmosis system, water is pushed through a filter with incredibly tiny holes in it. Most pollutants are too large to make it through the filter, so they get left behind.

    This leaves you with two bodies of water. The clean water is the stuff that was pushed through the membrane, while the wastewater is the liquid that didn’t make it through, leaving it full of contaminants.

    The system then pushes the clean water on to you while the wastewater is drained. Some units are more efficient than others, which means they have a better ration of clean water to wastewater than others.

    Many systems use several different filters, each of which serves a different purpose. However, there is usually only one reverse osmosis filter, and it’s placed toward the end of the filtration process.

    Are There Different Types of Reverse Osmosis Systems?

    Yes, there are three primary types: under sink, countertop, and portable.

    Under sink models are usually the most powerful of the three; however, they also take up the most space. As you might expect, these are set up under your sink and often require a fair bit of installation. You may need to drill a hole in your counter, and it’s best if you have at least some plumbing skills, as you may need to replace your existing faucet.

    Under-sink models can filter the most amount of water, and they often do so without a loss of water pressure.

    Countertop models sit on the counter. They’re either connected to the faucet or have a reservoir that you fill manually. These have a small footprint, but they can’t filter as much water as under-sink models. As a result, they’re best suited for smaller families.

    Portable models often look like smaller versions of under-sink models. You usually hook them up to your existing faucet; the water then travels from the faucet through the reverse osmosis system, coming out a hose at the end. Portable models are easy to attach and detach, but they usually take a long time to filter water.

    Most Systems Seem to Have Multiple Filters. What Do They Do?

    It’s important to realize that water filters have a limited lifespan, and the more junk they filter out, the sooner they’ll need to be replaced.

    As a result, many systems have multiple filters that they push the water through. The first one removes the largest pollutants, like silt and heavy metals; the filters get smaller as you go along, with the reverse osmosis filter being the smallest of the bunch.

    This prevents any one filter from doing too much work, thereby extending every filter’s lifespan. Since the reverse osmosis filter is the most specialized of the bunch, you want to limit the amount of work that it has to do as much as possible.

    woman drinking tap_shutterstock_l i g h t p o e t
    Image Credit: l i g h t p o e t, Shutterstock

    What’s a Tankless System and Do I Need One?

    Traditional reverse osmosis systems have a large tank inside them. As the system purifies incoming water, it puts the clean water in the tank; once the tank is full, the system stops working until you remove some water from the tank.

    This can give you a large reservoir of ready-to-drink water, but it gives the system a larger footprint. Also, it can take a long time to refill the tank once it’s empty, so you may have to wait a while for clean water.

    A tankless system doesn’t store any water; instead, it purifies as it goes. These systems often use several reverse osmosis filters. Water is pushed through them and comes out the faucet almost immediately (although there might be a slight delay). It usually tastes better too, because it hasn’t been sitting in a tank for a long time.

    Tankless systems are best for families that use a great deal of water or for people who don’t want a giant filtration system in their kitchen. However, they’re more expensive up front, and they cost more in the long run as well, as they have more reverse osmosis filters to replace.

    Divider 5

    Conclusion

    While the Waterdrop WD-G3-W was our favorite system overall due to its small footprint and powerful filtration abilities, every single unit on this list can work well in certain situations. That should make it easy for you to find the one that is best for your specific needs.

    We know that deciding on a reverse osmosis system isn’t a decision to be made lightly, and we hope our reviews have taken some of the stress out of the buying process for you. The important thing is that once you decide on a system, you and your family can enjoy clean, healthy water for years to come.


    Featured Image Credit: sonsart, Shutterstock

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