Updated: April 19, 2021 by Zac Harding
Most people would probably agree that having access to safe, healthy drinking water in your home is a high priority. This should really be a basic human right for everybody, but unfortunately, that’s not the case.
Even in America, there are still some homes where unfiltered water can complicate simple tasks like laundry, cause problems with appliances, or even have harmful health consequences.
You might turn on your faucet to see clear, cold water pouring from the spout, but how do you know that it’s as clean as it runs?
According to the Environmental Working Group (EWG) and their recent database findings, 81% of American water contains traces of contaminants that are linked to cancer.
It’s perhaps no surprise then that more and more people are making the decision to fit their home with a reverse osmosis system. This is one of the best and most effective ways of making sure that the water being supplied to your home is contaminant-free, filtering out up to 95 to 99% of toxins which can include but is not limited to lead, arsenic, nitrates, fluoride, bacteria, viruses, and more.
There are many advantages to having a water filtration system fitted, but don’t worry if you’re new to reverse osmosis because we’ll walk you through them all throughout this comprehensive guide.
Without further ado, let’s take a look at each of our selections in closer detail.
The iSpring RCC7AK system is the one that does a great job providing you with clean, safe water at such a reasonable price.
The Best Reverse Osmosis System Reviews
It combines GAC and CTO filters in the 2nd and 3rd stages in order to provide additional layers of protection against toxins. This system also contains a larger RO membrane than some of the models we’ve included in this list with a generous 75 GPD capacity.
Once it’s been through the purification process your water will not only taste better, but it will be free from the harmful chemicals that have been effectively filtered out.
You don’t need to worry about it stripping the water of its natural alkalinity and mineral balance in the process, either, as these are restored during the remineralization (AK) stage.
Best of all, it’s easy to install thanks to the clear instructions and video demonstrations, and there’s always their unparalleled technical support on hand to support you.
- You can be safe in the knowledge that your entire system is backed by a 1-year moneyback and manufacturer’s guarantee as well as lifetime technical support.
- The water is good for your health as the beneficial minerals are added back in after it’s been filtered.
- You can use it for a number of purposes, most commonly mounted on the countertop as a water drinking source, or connected to your ice maker or Starbucks coffee machine, etc.
- There are a few customer reviews that suggest there are quality control issues, but these are among the minority.
- You might need to block out the afternoon to install this one as the process can be a little tricky.
- Certified to NSF/ANSI 58, 6-Stage Alkaline Remineralization Layered Filtration: Exclusively designed to restore the natural alkalinity and mineral balance of water; this reliable and ultra-safe Reverse Osmosis (RO) water filtration system converts your water into clean, pure and healthy drinking water by removing up to 99% of over 1, 000 harmful contaminants like chlorine, fluoride, lead (removes up to 98%), arsenic, asbestos, calcium, sodium and more.
- BENEFITS: The iSpring RCC7AK water softener includes an additional sixth stage - an Alkaline Remineralization filter which restores healthy minerals and produces a balanced alkalinity, which gives your water a more natural taste than regular 5 stage RO water filter; the RO membrane removes not only harmful pollutants but also a few helpful minerals. As a result, a standard 5 stage RO system produces slightly acidic water with a pH of 7. 0 or below
- FEATURES: Beautiful European-Style kitchen faucet. Transparent 1st stage housing for easy visual inspection. Three extra long life pre-filters to remove large contaminants and protect RO membrane. Ultra fine (RO) filter to remove contaminants down to 0. 0001 microns; fine GAC filter to provide final polishing to the purified water and (AK) filter to finally restore just the right proportion of healthy minerals and a natural alkaline balance. The end result is great-tasting bottled-water quality
- EASY DO IT YOURSELF INSTALLATION: The water purifier is designed for do-it-yourself installation and all necessary parts for installation are included, backed by clear, well-organized written instructions, instructional videos, and access to iSpring unparalleled technical support. The entire alkaline water filter fits nicely under a standard kitchen sink. For leak-free installation, simply push tubing ½ inch deep into quick-fitting connectors and lock; no threading pipes needed
- 100% SATISFIED CUSTOMERS: RCC7AK from America’s favorite brand of under sink water filter is the No. 1 rated reverse osmosis systems in the USA backed by iSpring extended manufacturer upon registration and lifetime personalized support from GA, USA, combined with premium quality components, this water filter is to deliver endless bottled quality drinking water right in your home for many years to come, eliminating plastic bottles
Another quality RO system we’ve included is from APEC and features the only technology that successfully removes up to 99% of contaminants like chlorine, fluoride, arsenic, lead, nitrates, and more.
It has a maximum total dissolved solids of 2,000 ppm and feed water pressure of 40-85 PSI.
The premium long-lasting fillers can purify tap water and well water, so you’ll have the same great taste as your favorite bottled water for an affordable price, no matter what your water source is.
The system itself is easy to maintain and true leak-free fittings protection makes sure you have minimal trouble with it, even with regular use.
You can be confident in its reliable performance as the 5-stage filtration process includes high caliber components to further extend its lifespan and to ensure that it’s successfully removed all harmful chemicals.
- Your bank account will thank you as this is one of the more affordable choices.
- You can contact APEC’s excellent customer services if you experience issues.
- It’s a product you can trust due to it being a WQA certified system.
- You’re covered by a 2-year extended manufacturer’s guarantee.
- Finding replacement filters can be a challenge.
- You’ll be more aware of your system when it’s running as it’s a little loud during operation.
- Supreme quality - designed, engineered, and assembled in USA to guarantee water safety & your health.
- Only technology to remove up to 99% of contaminants such as chlorine, taste, odor, VOCs, as well as toxic fluoride, arsenic, lead, nitrates, heavy metals and 1000+ contaminants. Max Total Dissolved Solids - 2000 ppm. Feed Water Pressure 40-85 psi
- WQA Certified System. Premium long-lasting filters used to treat tap water, well water. Provide unlimited clean, refreshing crisp tasting water superior to bottled water
- America's No.1 rated water filter brand with 20 years of success guaranteeing trouble free, noise-free system for long lasting, dependable, pure drinking water.
- System comes with 100% lead-free designer faucet, plus Certified JG Food grade tubing and parts to provide safe, contamination-free pure water.Pipe Size: 1/4 inches
The RO5DX water filtration system from Express Water is one of the most affordable products we’ve looked at, but it still successfully removes 99.99% of impurities to produce safe drinking water. You can also save further costs by installing it yourself thanks to the easy setup instructions.
You might have to spend a little time on maintenance, as the product care manual recommends periodic draining and dismantling for cleaning.
On the other hand, the filtration system automatically refills your water tank for you, and it features quick connecting fittings that are both easy to upgrade, replace, or customize.
It should last you for a long time as there are safety features that protect this system from damage, such as the emergency leak stop detector that recognizes when the moisture levels are too high. Your purchase is also backed by a 1-year warranty.
- You can customize the system by adding filtration attachments like a UV water filter, alkaline water filter, or deionization water filter.
- Your drinking water will taste good and be completely safe.
- You’ll save money on the system and installation which you can do yourself.
- It’s recommended that you carry out maintenance that’s more thorough than other systems.
- Reverse Osmosis Water Filter: Experience what water should taste like with the Express Water reverse osmosis water filtration system removing up to 99.99% of Lead, Chlorine, Fluoride, Nitrates, Calcium, Arsenic, Bacteria, and more.
- Water Purification System: Drink the healthiest water on Earth. All our water filters are specially engineered to work together, producing the safest and best tasting water you’ll ever drink
- Under Sink Water Filter: Don’t waste money on professional installation. Express Water’s quick and easy-to-understand design means you can install and understand everything about your new water filtration system
- Quality Guaranteed: Rest easy with our 1-year warranty on all Express Water Reverse Osmosis Water Systems
- Under Sink Water Filter System: No need to mess with refilling or activating your water filter, Express Water’s water filtration systems automatically fill your water tank with high quality drinking water
This is an upgraded version of the previous APEC RO system we’ve already reviewed and it comes with a slightly higher price tag to match. It’s a 6-stage system that removes 99% of over 1,000 contaminants and it has a feed water pressure of 40 to 85 PSI.
You can be confident that it’s safe because the system is WQA certified, and the US-manufactured cartridges are made with food-grade calcium which enhances the pH levels of the water and increases the alkalinity for a better taste. Use it to purify tap/well water for unlimited drinking water.
Why not join the customers who clearly love APEC and have rated America’s No. 1 rated brand, boasting over 20 years of success!
Included with your purchase is a lead-free designer faucet, JG food-grade tubing, and all necessary parts, plus a 2-year extended warranty for peace of mind.
- You can enjoy tasty and ultra-pure drinking water with better alkalinity.
- It’s been WGQ certified as safe.
- You can rely on this system for long-lasting, dependable drinking water.
- You don’t need to rely on a water leak detector as the leak-free quick connect fittings are extremely high quality.
- You might have a little trouble resolving issues as their customer services are somewhat lacking.
As the first system with composite filters and a tankless design, it provides 7 stages of filtration with a three-in-one filter and an innovative RO membrane that’s highly effective at purifying water. As a result, you’ll be able to better filter out secondary pollution.
It tastes great thanks to activated carbon block filters made from natural coconut shells. If you’re concerned about wasting water, this system wastes up to 300% less than other models so you’ll save on your water bills and on space.
- It has a large 8.5-gallon water capacity and purifies water quickly with a 400 GPD flow rate.
- You’ll breeze through the easy installation process with the help of a blue light indicator.
- Quench your thirst practically immediately as it takes just 12 seconds to make a cup of pure water.
- It’s a more expensive option.
- Water can have a high PPM.
- Three filters are included in the package. Search "Waterdrop WD-G3-W Filter" for replacement filters
- [NSF Certified performance]: The system is certified against NSF 58 for TDS reduction. Using reverse osmosis filtration technology with a filtration accuracy of 0. 0001μm, the system can effectively remove most contaminants including fluoride, TDS, limescale, and heavy metals in your tap water. System is also NSF 372 certified for lead free material
- [Smart, easy-to-install design]: Waterdrop RO water filtration system is an innovative, all-in-one intelligent water purification system. In just a few minutes, Waterdrop RO system can be installed completely, and in just three seconds, the filter can be changed with one single turn. Installation is that easy
- [The first composite filter element]: It is the first smart RO system with composite filters and tankless design in the U. S. market. The three filters provide seven stages of filtration. The pre-sediment and carbon block filter is a 3-in-1 filter that functions as that of three filters combined. The Reverse Osmosis membrane filter adopts an innovative design, and the efficiency of the filter equals more than three stages of filtration. Additionally, the activated carbon block filter uses high-precision activated carbon granules made from natural coconut shell, which will also improve the water taste
- [No-tank design]: Use new composite filter element technology to more efficiently filter out harmful substances. The tankless design helps you avoid secondary pollution and enjoy more storage space in your kitchen
Another slightly more expensive option is this RO system from AquaTru which is certified at removing harmful contaminants to provide your home with safe drinking water.
You won’t need to hire a plumber as the setup is simple and takes mere minutes to complete! It comes with quick-change twist and seal filters that last between 6 months and 2 years, so maintenance is minimal, and just 1 filter replaces 4500 plastic water bottles.
It has health as well as environmental benefits, as this system removes more impurities from your water by up to 15% compared to other brands.
It was tested by IAPMO in line with NSF/FANSI standards which showed that it removes 82 contaminants and 1000s of pollutants.
- Easy ‘plug-in and purify’ setup.
- It’s cost-effective thanks to the long-lasting filters.
- Your water will taste better after filtering out virtually all contaminants.
- It’s an environmentally conscious choice as one filter equates to 4500 plastic bottles.
- Not the most durable system as some customers report breakdown issues.
- IS YOUR WATER SAFE TO DRINK? Studies continue to pour in regarding Toxins, Hormones, Microplastics, Cancer-linked contaminants, known Carcinogens and other toxins discovered in our Tap Water, Filtered Water…and yes, even Bottled Water. Arsenic, lead, chromium, and drug residues are commonly found in municipal drinking water. AQUA TRU's patented Ultra Reverse Osmosis water filtration system is CERTIFIED to remove such contaminants and many more!
- Tested and certified by IAPMO according to NSF/ANSI standards to remove 82 CONTAMINANTS - that's 15X more contaminants than the leading pitcher filters. Removes such toxins as Lead 99.1%, Chromium 97.2%, Copper 95.2%, Fluoride 93.5%, Radium 96.4%, and Chlorine 96.6% (to name a few). In fact, it's designed to remove 1000's of pollutants that could be lurking in your tap water. Taste the Difference!
- NO PLUMBING OR INSTALLATION required - takes just minutes to set up. AquaTru’s Trusted & warrantied RO countertop system COSTS CONSIDERABLY LESS than fully installed under-the-counter RO systems, while at the same time, delivering often Cleaner, Purer, and Better Tasting Water. Why waste money & add to landfills with bottled water (93% recently found to contain micro-plastics)? 1 SET OF FILTERS REPLACES 4500 PLASTIC WATER BOTTLES (16.9 oz) - Forget about the hassle & cost of buying bottled water
- QUICK CHANGE TWIST AND SEAL FILTERS come included with your first AQUA TRU system, and last from 6 months to 2 years. SLEEK COMPACT DESIGN - 14'' Tall x 14'' Deep x 12'' Wide - Purifies 1 gallon of tap water into bottle-quality water in 12-15 minutes.
Their patented remineralization process increases calcium and magnesium levels twice to reduce storage tank degradation and to produce excellent-tasting water that’s as healthy as it is pure. The fast flow rate means you don’t have to wait long for your water to be ready thanks to large tubing.
The 7-stage filtration process removes 99% of contaminants and the entire system is BPA and lead-free. Every component meets NSF-certified standards and there’s a generous 5-year warranty to protect your purchase.
- Easily customize or upgrade the modular design.
- It includes everything you need including unit, filters, DOW membrane, tank, adaptor, chrome faucet, and drain saddle.
- Your drinking water will be healthier as it removes the bad stuff but replaces the good stuff.
- You may notice a drop in quality after a few years of use.
- A better RO system | Home Master Artesian Full Contact’s innovative design solves most common problems associated with cannister and tankless RO systems
- Mineral Water on Tap | Patented remineralization system adds calcium and magnesium twice during the purification process for reduced storage tank degradation and great tasting, highly pure Mineral Water on Tap
- Highly pure water 7-stages of filtration, purification and enhancement remove up to 99% of Chlorine & Chloramines, chemicals, lead, heavy metals, fluoride, microplastics, TDS, and thousands more. BPA and Lead free. 5 Year Limited Warranty
- NSF Certified Components meets or exceeds NSF standards for material safety and performance. NSF listed company. Made in USA
- Faster Flow Rate Included Fast Flo RO Kit has larger fittings and tubing provide twice the flow of traditional RO systems
You’ll be impressed by how easy it is to change the filter compared to some units thanks to the ultra-ease technology which ensures hassle-free replacement, and the compact design of the 3-stage system saves space in your home as well as having fewer filters to change.
The filters you do have are long-lasting and will purify water for years to come, as does the high-quality RO membrane which effectively eliminates any chlorine taste or odor, and removes sediment, cysts, lead, and chemicals.
- Minimal hassle for you as it’s easy to install and maintain.
- You’ll save money on buying bottled water by purifying your own at home.
- The space-saving design means it won’t take up too much room.
- It produces a lot of wastewater which is noisy to drain.
- Better than bottled water — Reverse Osmosis filtered water tastes better than bottled water — Convenient, unlimited and refreshing, and for a fraction of the cost of bottled water.
- Safer drinking water — Reduce chlorine taste and odor, sediment, cysts, lead, chemicals, and dissolved solids that show up in unfiltered tap water.
- Change your filter in seconds — Ultraease Technology allows for easy and hassle-free filter changes with no open sumps.
- Save space — our 3-stage system does as well or better than competitors systems despite their 5 and 6-stage filters, with fewer filters to replace!
- Extra long filter life — Get clean, fresh-tasting water with fewer filter changes and a membrane that lasts for years
You can also use it for household or commercial purposes thanks to the powerful tested flow rate of 18L per hour at 60 PSI, which can produce 1 cup (200ml) of fresh water in an impressive 5 seconds.
It’s money-saving in two ways as it’s affordable to buy and easy to install so there are no additional plumbing costs to consider. It doesn’t run on electricity which also saves on your energy bills, and you’re covered by a lifetime warranty including all manufacturer faults for refund or replacement.
- You can install it yourself as the process is easy to follow and they have a helpful customer services team.
- It may be small in size, but it has a high flow rate for fast water purification.
- Enjoy safe, clean water with an improved taste for the lifetime of your product thanks to a generous warranty.
- Its small size means filters are less readily available.
- Supreme quality - designed, and assembled to guarantee water safety & your health.Remove Rate up to 99.999%，including chlorine, taste, odor, VOCs, as well as toxic fluoride, arsenic, lead, nitrates, heavy metals and 1000+ contaminants.Experience clean, safe, good-tasting water every time you turn on the faucet. Enjoy crystal clear ice cubes, fresher tea and coffee, better tasting foods, healthier baby formula – even better than most bottled water.
- Mini Size -High Flow Designed :Developed for household and commercial use, This Water Filtration System can be installed in your kitchen, bathroom, RV, or office .The tested full flow rate is 18L per hour at 60 Psi,means you can get 1 cup (200ml) of pure,fresh and great tasting water in 5 seconds.Completely satisfied with your daily water needs.
- Easy, do-it-yourself installation, Fits under a standard kitchen sink, with all parts included and clear, well-organized instructions and videos. Don’t need waste money on professional installation. quick and easy-to-understand design means you can install and understand everything about your new water filtration system.
- Money-saving:The Reverse Osmosis System works without electricity and 1: 1 low drain ratio,thereby reducing the amount that you spend on electricity and water.On average, by spending only $50 per year (13 cents per day) for the filter replacement, you and your family can enjoy safe and clean water.
- FS-TFC FILTER LIFETIME WARRANTY: FS-TFC Water Filter cover all manufacturing and other defects with our Lifetime Warranty.If you don't love your FS-TFC Water Filter,simply return it and we will refund 100% of your purchase.
Its shape is compact enough to fit under your sink and the sleek filter and tankless design eliminates secondary pollution. Changing the filter is easy and the smart LED display will track the TDS to tell you when this needs doing with a useful color-coded indicator light.
This is a great option if you’re hoping to quench the thirst of the whole family thanks to the larger capacity, as it can produce 600 GPD thanks to a high water flow. It’s also super-efficient and saves up to 450% wastewater compared to other systems so you’ll spend less on your water bills.
- All parts are included with purchase and there are helpful instructional videos you can follow if you experience issues.
- You can install it yourself thanks to the simple setup process saving money on plumbing costs.
- Fast filtration and purification mean you can fill a 330ml cup in 10 seconds.
- The remineralization stage adds beneficial minerals back into the water post-purification.
- There isn’t a support number so issues will need to be dealt with via email.
- 【Remineralization & Alkalization Under Sink Water Filter】: The water from RO membrane is slightly acidic, which also removes natural mineral. The 3rd stage of filter solves both issues of conventional RO systems! It balances the alkalinity of RO water and adjusts the PH to more than 7.5. Drinking weakly alkaline water is beneficial to your health. It also restores health-benefiting essential minerals to your water. Frizzlife PD600 produces healthiest and greatest tasting water for you.
- 【No Tank Design Under Sink Reverse Osmosis System】: Frizzlife PD600 adopts tankless design. Compact and sleek filter system with a small and convenient footprint takes up less space, saves storage under kitchen sink! No tank also means no more secondary pollution. Guaranteed to provide ultra-pure, safe and clean water for you and your family.
- 【600 GPD High Water Flow】: PD600 Reverse Osmosis water filter system adopts internal prompt and can produce 600 gallons water per day. High capacity can serve the daily water needs of large family. Water flow is fast and stable, the system can fill a 330ml cup of water in about 10 seconds. Get a full cup of fresh RO water in a snap!
- 【1.5:1 Low Drain Ratio】: Thanks to advanced water-saving technology, Frizzlife PD600 RO system maximizes the efficiency and can save your water up to 450% compared with conventional RO filter systems on market! Being both economic and environmental friendly, it makes your water bills more affordable. Over the life of the system, PD600 RO filter system pays for itself in water savings!
- 【Smart LED Display & Quick Change】: The smart display panel clearly tells real-time out TDS and remaining lifespan of each filter. The built-in TDS system constantly monitors the quality of your drinking water 24/7. Acting as a intelligent reminder, the color-coded indicators will always remind you to change filters in advance. With all parts included and well-organized instructions and videos, Frizzlife PD600 RO filter can be completely installed in a few minutes by yourself.
What is a Reverse Osmosis Filtering System?
Considering that the human body is made up of 60% water, with every human cell containing around 65 to 70% water each, and the fact that drinking 2 liters of water per day is the official amount that’s recommended by health experts, it’s fair to say that water plays a huge role in our everyday lives.
So, what is a reverse osmosis filtering system? How can it benefit you or improve your quality of life?
Let’s break this down and take things back to the basics: if you can recall anything from your high school science lessons, you may remember the term ‘osmosis’ from when you studied the life cycle of a plant in biology.
Plants can absorb water from wet soil because their roots have a higher solute concentration level than the soil around them which allows water to travel up through the roots.
This process of water molecules traveling through a semipermeable membrane where two solutions with different levels of concentration meet is called osmosis, and it moves the molecules of a solvent from the side with the less concentrated solution to the more concentrated solution.
You might be thinking, great, thanks for the school science recap — but I’m still not sure what any of that has to do with reverse osmosis filtration systems? Don’t panic, we’re getting to that part now!
A reverse osmosis filtering system is a highly effective method of purifying the water in your home because it successfully uses this same process of transferring molecules from one area to another to remove impurities from the water.
The small pores and the ultra-thinness of the membrane layer when using a semi-permeable membrane filter ensures that only certain small particles can pass through, effectively trapping them whilst keeping the rest of the potentially toxic molecules out.
What to Consider When Buying a Reverse Osmosis System
There are a few things that you should consider before deciding to install a reverse osmosis water filtration system in your home, including the following factors:
The amount of storage space you have should be one of, if not the very first factor you consider when you’re thinking about having a reverse osmosis system installed.
It should be pretty obvious why, as otherwise, how will you know where to install it? Will it even fit the intended space?
These are the questions that you need to ask yourself before you even start thinking about what brand you want to go for or the number of filtrations you’ll put it through.
If you think there’s going to be a problem finding an appropriate spot to store your reverse osmosis system you could always build your own form of storage or box in the system after it’s been installed in the desired location.
PSI is the measurement that is used to track the water pressure per square inch. The minimum pressure level you could scrape by with and still function at is 40 PSI, so it’s vital that you periodically check the water pressure level of your house to make sure it doesn’t fall below this suggested amount.
You can do this using a water pressure gauge kit which will tell you the exact pressure level.
The reason PSI is so important is because of how it helps the water travel around the filtration system, as it affects the amount of force with which the pumps are able to push the water through repeated layers of membrane until it’s purified.
Knowing how much water your household typically uses will be really useful when you’re trying to decide on a reverse osmosis filtration system because most manufacturers categorize their products by the size of the house, from a 1-bedroom flat to an entire floor of office space.
It’s always better to overestimate rather than underestimate when it comes to your water usage due to how easily and quickly you would end up burning through a system that’s too small as it attempts to keep up with demands that are beyond its capabilities, leading to damage or more maintenance.
One of the ways you can learn more about how much filtration is required for different waters is by tracing it to its source, although this is sometimes easier said than done.
Dense cityscapes and busy towns usually rely on a treatment plant to provide their water, whereas you’re more likely to come across a well in areas that are more rural and rustic. When it comes to freshwater, the source is usually either a small river or reservoir.
The whole point of a water filtration system is to remove some of the unwanted minerals and molecules that are able to hide in plain sight in the otherwise crystal-clear water.
However, reverse osmosis systems can be so effective that they’re considered a little bit too effective by some people.
As well as drawing out impurities, reverse osmosis can also take away a lot of the good minerals that means you miss out on most of the health benefits associated with drinking water. This can alter the taste of the water too which can influence how much you drink throughout the day.
Remineralization is an effective solution to this flaw in reverse osmosis filtration, as it’s a good way of adding the missing minerals back into the water before you drink it but after it’s been filtered.
Certain systems come with a built-in remineralization filter, but others require separate purchase.
It might seem a little pre-emptive if you’re still on the fence about your decision to invest in a reverse osmosis system, but thinking about replacement filters early and making sure you’re stocked up with a few spare ones before you actually come to need them is something that future you will definitely look back and thank you for.
Also think about how easy it will be to install the filter and how many times you’ll have to do this (i.e., how long the filters will last before they need replacing again), as this can inform your decision when you’re trying to choose between manufacturing brands or which model you should go for.
How Does Reverse Osmosis Work?
While the exact process can vary between system setups and manufacturers, the main method used for reverse osmosis filtration is unchanging.
This is essentially a method of purifying water by filtering it through one or more pre-filters, the RO filter itself, and finally, one or more post-filters.
The reverse osmosis membrane is the real star of this filtration system, and as such, it’s important to make sure that it’s in good condition. That’s where pre-membrane filters come in.
Pre-membrane filters help to maintain the quality (and therefore the effectiveness) of your RO membrane. As the first barrier in this filtration system, these filters prevent larger, potentially damaging molecules from passing through, so they don’t reach or damage the RO membrane filter.
The filter(s) can keep out any solids or sediments, such as rust, sand, and chlorine, by engaging a 5-micron filter at the beginning of the reverse osmosis process.
The reverse osmosis (RO) membrane is much finer, and it can filter out anything that exceeds 0.001 microns leaving what is essentially purified water behind, which is the whole point after all.
The ultra-fine pores successfully remove up to 99% of unwanted particles and any solids that have dissolved in the water, but the water pressure can have a huge effect on this process.
Remember, the higher the water pressure, the faster the water will be pushed through the filters for purification.
Post Membrane Filters
Post filters are like a bonus filter that can be used as the final step in this process to minimize any lingering bitter flavors.
If you notice that there is an odd taste to the water, the addition of a carbon-based filter at this late stage can help to get rid of it before storing the purified water in a tank where it can remain until it is needed.
Reverse osmosis is a system designed specifically to deal with hard water and the “hard” minerals it contains. The aim of this is to remove certain substances like calcium and magnesium in particular, which helps turns it from “hard” to “soft” water; the latter being kinder to your clothes and health.
It is important to recognize that despite their excellent filtration properties, a reverse osmosis system should not be used as a replacement for an existing water softener, as around 85% of U.S. households reportedly have a hard water supply and would benefit from installing a water softener.
Hard water is tougher on your filters and it can exacerbate any wear and tear on your reverse osmosis filtration system, as well as causing problems relating to your appliances, your household plumbing, and even the people residing within your household, so a water softener is worth having.
Many reverse osmosis systems feature additional accessories that help to improve various parts of the filtration system.
This can include UV lights, permeate pumps (which increase the in-flowing water pressure levels), and components that serve remineralization functions.
We’ve already touched on remineralization filters and how you can find certain systems that come with these already built-in, but a lot of the time you will need to purchase these separately.
Even as an additional accessory, it’s worth getting yourself one of these to bump up your mineral intake.
Minerals such as calcium, magnesium, and occasionally even potassium can be reintroduced to the purified water using a remineralization filter, which can have numerous health benefits as well as improving the overall taste of the drinking water.
This also means that the water will become less acidic and more alkaline, which increases the overall pH level of the water.
Households with low water pressure or those concerned about water waste will undoubtedly benefit from having a permeate pump.
Electric pumps are also an option, but they’re not as common and don’t come as highly recommended as some of the permeate pumps we’ve looked at in this article.
Permeate pumps work to increase the water pressure as it passes through the system. Water output increases by around 50% while the quantity of water used to flush the RO membrane is reduced.
The standard 4:1 ratio of water wasted to purified water becomes 1 gallon used to produce 1 gallon of purified water, so there are clear benefits to having one of these added post-system-installation.
For even higher levels of efficiency, you can also look for a system that includes a powered booster pump that maintains the water pressure levels in your reverse osmosis filtration system.
Some of the high-end reverse osmosis systems will come with an Ultraviolet (UV) light already included, but it’s surprising how many don’t when you consider the benefits it can bring.
UV light is as effective as boiling your water and is used to kill bacteria, viruses, and up to 99.9% of any other microorganisms that could be lurking in the water you unthinkingly drink.
It’s an extra source of protection that can catch any of the microorganisms that your RO filter might have missed, which is especially useful if your water source is of questionable quality, like water brought up from a well where microorganisms thrive.
The water that you drink if you live in a busy city will typically have already been filtered but the fact that it travels through underground pipes that are potentially old or dirty can mean that it’s less sanitary once it reaches the faucets in your household, so filtering it again is beneficial.
If in doubt you can test your water to see how contaminated it is and whether it would be worth it to install a UV light in your RO filtration system.
The good news is, you can choose to do this at any point after the system is installed, so you can test the water before making an immediate decision.
Reverse Osmosis Terms
No guide would be complete without at least running through a couple of the key terms that are often associated with reverse osmosis systems to make sure you have a full understanding of what they mean.
You might not have heard of all of them before, but here are some important terms you should know if you’re thinking about having a reverse osmosis filtration system installed.
The stages in your reverse osmosis system determine every step in the filtration process, each being responsible for its own unique function that furthers the filtration of the water.
You don’t really need to pay much attention to the number of stages there are in your reverse osmosis filtration process as this isn’t a measure of the system’s quality, although the more stages there are, the more work that’s being done to ensure your water is purified at the end of it.
The best home reverse osmosis systems designed for under sink installation will include a pressurized storage tank which can be used to hold purified water after it’s been filtered through the reverse osmosis process.
Pre-filling this tank means you won’t have to wait as long for a response from your faucet because you’ll have a store of purified water ready and waiting.
If you find that this isn’t enough and that you’re depleting your purified water stash on a frequent basis, you can always replace the standard storage tank with a larger model which will allow you to store more purified water at a time.
The other option is to research some of the tankless reverse osmosis systems that eliminate the need for a tank by filtering the water at a faster rate.
The water output of your RO system is a way of measuring how much water you can filter in one day.
It’s not always the easiest to calculate due to the varying conditions that can influence water output, and it’s worth keeping in mind that the actual output for your RO system may be significantly lower than what the product information and data suggest.
The water output level can be affected by low pressure, low temperature, and high TDS levels, but low pressure is often the most common culprit for causing a drop in water pressure.
Luckily, there’s the simple solution of adding a permeate pump which can increase your output by around 50% per day! The effects of low temperature can also be mitigated by adding a length of coiled water pipe on either side of the filter, as this heats the water before it enters the membrane.
Wastewater is sometimes held up against the removal of beneficial minerals as one of the main drawbacks to reverse osmosis filtration systems, as this affects its overall level of efficiency.
However, you can always use up any water waste the next time you need to wash your car, for example, to make use of the otherwise wasted water.
This is provided that the TDS level falls somewhere between 1,200 and 1,500 PPM, as anything higher than that will need to be diluted by adding some tap water to the wastewater.
The pH scale is a system used to determine how acidic (low pH) or how alkaline (high pH) your water is. It can also indicate what the water will taste like, as some people claim that the lower pH of purified water is what causes it to be quite bland.
Remineralization is a great option if you’re fussy about favor, as the added minerals increase the pH level to neutralize it and improve the taste.
According to the EPA Secondary Drinking Water Standards, manufacturers should accept water with a pH level that falls between 6.5 and 8.5, so we’ve tried to include options that accept a range of different pH levels in the feed water.
An acronym for ‘total dissolved solids’, TDS typically refers to inorganic salts including calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfates, in addition to a few trace amounts of organic matter which naturally dissolve in the water.
You can measure dissolved solids either by testing under controlled conditions in a lab or by measuring electrical conductivity. While the former is more accurate, it’s also more expensive.
The EPA states that the maximum TDS level should be 500mg/L or less to be considered safe as drinking water and a quality reverse osmosis system will lower the TDS quantity by up to 90%.
Air Gap Faucet
Having an air gap faucet can come in handy if you ever end up with a blockage somewhere in your water system, like your sink, for example, as it prevents the dirty or unfiltered water from re-entering the reverse osmosis system, sort of like a break in the circuit.
When used in conjunction with your reverse osmosis filtration system, there’s a much lower risk of you or anyone else in your household accidentally ingesting dirty water as a result of faulty filtration.
Not only this, but it also has a good chance of lowering your home insurance premiums which will save you money on your bills.
In certain states in the US, it’s actually a legal requirement to have an air gap faucet installed when you put a new reverse osmosis system in your home. For this reason, it’s not uncommon to find air gap faucets available to be purchased as part of a bundle included with a reverse osmosis system.
Installation and Maintenance of RO Systems
Due to the complex nature of reverse osmosis systems, installation can be tricky, especially if it’s a whole house system or a big-scale installation, so we would generally recommend hiring a professional.
RO filtration systems require a permanent connection to the cold-water feed pipes and waste pipes, but someone with DIY experience could probably handle a smaller install job like this.
You can choose between a standard faucet or an air gap faucet when it comes to picking a faucet type. It’s worth noting that certain states require an air gap faucet to be installed with any RO system (not that this is always adhered to…) and that some sinks feature a covered hole, an integrated soap dispenser, or a spay hose opening for your reverse osmosis faucet.
For standard RO faucets, you’ll need a ½” to 5/8” hole, whereas an air gap faucet will need a 1 ½” opening that potentially requires drilling through the countertop, meaning it’s harder to do yourself. Luckily after you’ve made this decision the rest of the installation process will be much simpler.
The exact process will obviously vary depending on the type of system you use, but as long as you follow the instructions closely most systems can be installed yourself. If in doubt, you can hire a plumber to install it at an extra cost.
Our best tip is that for the first few days it’s a good idea to keep an eye on the newly installed system to make sure it stays leak-free.
Carrying out the necessary maintenance is essential if you want your RO system to last for as long as possible without issue, but the type of maintenance required will depend on your system.
This includes tasks like replacing the filters. It’s a good idea to replace your pre- and post-filters every 6 to 12 months but you can judge this by your usage. You can also test the water using a TDS meter before and after purification.
RO membrane filters can last longer and won’t need replacing until after 1 to 5 years, but their lifespan can be extended by changing the pre- and post-filters regularly.
You can change the filters of most RO systems fairly easily by lifting it at the base and pressing a button on the side, or by pulling the old one out and slotting in the replacement. Alternatively, some filters are encased in housing which can be unscrewed to change the filter cartridge.
Aside from this, reverse osmosis filtration systems require very little maintenance.
It’s important to make sure you are providing your family with good and safe water to drink that is free from disease and unwanted chemicals. All the reverse osmosis water filter reviews in this article would make a great addition to your home, but we think the iSpring system stands out and is our pick for best under-sink reverse osmosis system.
We hope our complete guide has given you the tools you need to choose the best reverse osmosis system for you and your needs.