Within the past couple of years years, we've seen a rising demand for the best reverse osmosis systems in the US. It does everywhere else, with the global market valued at US$6.5 billion in 2017 and estimated to reach more than US$9 billion by 2022, according to a report from Research and Markets.
With years of increasing thirst, reverse osmosis (RO) water is apparently seen as more than another health fad.
If you're new to them, this article was composed to guide you through the basics of RO water filtration systems: what they do, how they work, and the benefits and risks of drinking RO water. You will also find what makes a good RO filter, and our reviews of the best systems on the market as of 2023.
What Is A Reverse Osmosis Water Filter?
A reverse osmosis (RO) water filter is a filter that employs the reverse osmosis process to purify water. RO filters can remove large amounts of pollutants from drinking water, making it clean and safe for consumption.
The RO filter can work as a semipermeable membrane on simple appliances such as the filter bottle for campers. However, since they take time to produce clean water, and need relatively clean feed water, RO membranes typically come with other pre-filters in a complete system.
This setting is usually seen on sink-top filters, under-sink systems, or whole-house systems.
How Does Reverse Osmosis Work?
RO filters get their name from the process they take advantage of to filter water: the reverse osmosis process.
Osmosis happens naturally where a solvent from a low concentration region passes through a permeable membrane to a high concentration region. Reverse osmosis is the opposite of osmosis: the solvent is forced by hydrostatic pressure from a high to a low concentration area.
This can be explained in simpler words in the context of water filtration.
During reverse osmosis, the contaminated water is forced by water pressure to travel through the membrane to the other side. Since the pores on the membranes are really small (sometimes as small as 0.0001 micron - smaller than a human red blood cell), only pure water molecules will pass through. The impuritants are rejected, and are later washed away in the wastewater.
RO filters are extremely efficient at water pollutant removal. They can remove more than 90 percent, and up to 99.99 percent of heavy metals such as lead, mercury, nickel, iron, etc. These filters are also known to reject algae, viruses and bacteria, and even hormones, pesticides, and herbicides.
Reverse osmosis filters do not require electricity to operate. However, they do need stable feed water pressure to force pure water through the membrane, and won’t operate if water pressure is too low.
The filters also require a large amount of water to wash away the contaminants for every small amount of pure water made, with a rate of pure water:waste water being 1:1 on the most advanced systems with permeate pumps. Mileage may vary vastly among different systems, so it’s important to check this rate to make sure you get the ones with high efficiency.
Reverse Osmosis Water Benefits And Risks
Like everything else, RO water has its benefits and drawbacks.
The benefits of RO water
Reverse osmosis water is basically pure water, and there’s no need to explain how water is good for you. Not all types of water are created the same, however, and compared to tap water or well water, there are remarkable benefits to RO water.
- Free of lead
We like to think our water is free of heavy metals, but the ugly truth is our piping system can sometimes release deadly substances into the water. And that has happened, when the old water infrastructure was found to release lead, potentially affecting the brain development of thousands of children in Flint, Michigan.
If there are concerns of lead in your water, an RO filtration system or bottled RO water should be considered. RO filters can remove up to 99 percent of the lead present in the feed water, lowering the amount to a safe level.
Not only lead, but a large amount (more than 90 percent) of other heavy metals, such as nickel, copper, iron, arsenic and mercury is rejected by the RO system.
- No cysts, germs, and viruses
With its tight pores, a RO membrane does not allow giardia and cryptosporidium - the parasites that are the culprits of a wide range of gastrointestinal problems. It removes a majority of other germs and viruses too, including Salmonella and e. Coli.
- Sodium free
If you have a salty water source, or are using a salt-based water softener in your home, chances are your water is loaded with sodium.
An RO system takes care of the salt in the water, eliminating the risks of high sodium intake for your family. RO water is also used in fish tanks to create a safe living condition for freshwater fish.
- Softened water
Not only sodium, but an RO system can also remove other minerals in the water, essentially softening it. RO water thus does not leave limescale or residue on your appliances, such as your faucet, sink, kettle, pots, or fish tank.
You usually need more soap/detergent when washing with hard water because the minerals interact with the fatty acids in the soap and essentially neutralize it. This won’t be the case with soft water, which RO water is, as there are little to no minerals in it.
All that said, there is a flip side to the RO water coin.
The risks of drinking RO water
There’s a thing with RO water: it is inferior to natural water in terms of trace minerals.
In nature, water travels through different layers of the earth before it reaches the underground rivers, absorbing healthy elements (together with the pollutants) along the way. Municipal water treatment typically does not remove these elements.
The RO membrane, while effective at removing illness-causing heavy metals and germs, does not give a free pass to the trace minerals. Its acceptance of the substances in water is based purely on size, and it isn’t selective between healthy elements and dangerous impuritants.
RO water, as earlier stated, is essentially pure water. Drinking pure water itself can’t harm, except in the case when you’re drinking excessively and “overdose” on it, but there are potential issues stemming from the lack of minerals.
- Reduced mineral intake
Fortunately, a very low percentage of our mineral intake comes from water. However, if you’re already suffering from a deficiency of minerals, switching to RO water can worsen your deficiency in the long term. You may want to consider making up for the loss by taking supplements or adding more minerals-rich foods into your diet.
- Loss of minerals in food prepared with RO water
Soft water, which RO water is, is believed to be the culprit for the loss of various minerals from foods cooked in it. Since water tends to bound to everything, it takes away the essential elements from the foods.
That said, if you also eat or drink the soup you cook your food in, then you will still consume all the minerals.
To minimize the risks associated with low mineral content in RO water, many RO filter manufacturers have incorporated a remineralization stage into their filtration systems. After the water goes through the membrane into the tank, a small amount of calcium and magnesium will be reintroduced to make up for the losses and increase the water’s alkalinity.
Is Reverse Osmosis Drinking Water Safe And Healthy?
Knowing all the benefits and risks of RO water, it’s your best choice for health if any of the below applies to you:
- There are concerns over contaminants in your drinking water.
- You have a weakened immune system, or are allergic to one of the contaminants in your home water.
- You have skin irritation and need pure water for personal hygiene needs.
- The smell of your drinking water is unappealing.
- You’re hydrating yourself with caffeinated, carbonated, or sweetened drinks rather than fresh water.
- There is an aquarium in your home.
- Your pets are drinking too little water and you suspect it has something to do with the water odor.
If you have concerns over the lack of healthy minerals, remineralized RO bottled water or an RO filtration system with a remineralization stage should help.
Reverse Osmosis Filter Pros & Cons
Before making your decision on whether an RO filter is what you want or need, it’s important to understand the benefits of these filters, as well as their drawbacks .
Reverse osmosis filters are the number one recommendation when it comes to making pure drinking water. And there are good reasons.
- RO filters are effective
RO filters are extremely good at removing contaminants from the water.
This is because RO membranes have tiny pores on them. These pores can be as small as 0.0001 micron on high-end filters, and are extremely restrictive. They allow essentially only water molecules through, and keep most disease-causing pathogens, dissolved salts, heavy metals such as lead, chrome, copper, and nickel, along with pharmaceutical contaminants from passing through the membrane and getting into the filtrate.
As a result, RO water is very close to purity. Not only is it safe and healthy to consume, it’s also free of any unpleasant odor or taste.
Some RO systems also include a remineralization process, during which healthy minerals are re-introduced into the water, making it more alkaline, and thus, more enjoyable to the tastebuds and potentially to your health.
- They’re better for the environment
Since RO filters can make bottle-quality water, it reduces, if not eliminates the need for bottled water (which, in many cases, is made using the exact same technology).
An under-sink RO filter can produce about 50 - 75 gallons of quality drinking and cooking water per day. That’s more than enough for the biggest family, as the daily requirement is only 0.5 to 1 gallon of drinking water for an average person. Imagine how many plastic bottles such a system can save from being discarded into the environment per year if you’re committed to it.
- Energy efficient
While extremely effective at purifying water, RO filters require no electricity to operate. Instead, the RO membrane takes advantage of the water pressure to push water molecules through and wash away the contaminants.
When the flow is too weak, a permeate pump is usually employed to increase feed water pressure. The permeate pump also does not use electricity.
If your RO system requires the use of battery or direct current, it’s most likely for the filter life indicator light, UV light, or other accessories, not for the filter itself.
- Easy maintenance
Once installed, RO filters require very little maintenance. As long as all connections are made secure, you can practically forget about it until it’s time to change the filters.
Most of the time, you will have to change the pre-filters every 3 to 9 months, depending on the filter capacity and your water condition. The RO membrane typically only needs changing once every 2 - 5 years, or at most once every year if your water hardness level is particularly high.
While being one of the most well-trusted household water filters, RO filters come with their own set of disadvantages.
- High initial cost
Since RO membranes are quite prone to clogging, they do not usually operate on their own, but rather in a complete system along with other pre-filters.
A typical RO filtration system has at least one sediment filter, one or more activated carbon filters, an RO membrane, a tank, and sometimes also a faucet and UV light. With that, RO filters have a much higher starting price than conventional or simple filters.
Plus, the complexity in the system also translates to difficulty in installation. If you’re a novice in plumbing work, you may need the help of a professional, whose cost sometimes ends up being higher than the whole filtration system itself.
- They’re slow
It’s a lengthy process for water to travel through the tiny pores on a RO membrane. RO filters thus typically come with a tank to store the filtrate. However, if you use a lot of filtered water at once, then you will have to wait for quite a while for the tank to refill before pure water is available again.
- High water waste
RO filters are particularly infamous for the large amount of water they “reject”.
They typically need 2 to 4 gallons to wash away the contaminants for every single gallon of pure water produced. Even the most high-end RO filters will produce waste water, except usually at a lower rejected water:pure water rate (1:1). This waste water can be drained to a separate line for car washing, watering, or other cleaning and non-drinking purposes, otherwise you will see quite a hike in your water bill.
Reverse Osmosis Water Efficiency
There’s this truth about reverse osmosis filters: they always produce a large amount of “waste” water for every gallon of purified water.
If you read about how RO systems work, you will see that they actually do not remove the contaminants from the water, but rather separate pure water from contaminated water.
After the reverse osmosis process, there will be 2 liquid products: drinking water with no or a very low amount of pollutants, and wastewater with all the remaining contaminants in it. The clean water:waste water ratio used to be as high as 1:7. On more modern systems, the general consensus is about 1:3 to 1:4. With a permeate pump, you can actually take it down to 1:1.
If this wastewater is to go directly into the drain line, which used to be the case in many households, even the 1:1 ratio seems unfathomable. Thankfully, modern RO systems are shifting towards incorporating the “wastewater” into the piping system for other purposes.
After all, the “wastewater” has gone through all the pre-filters and has a majority of impurities removed from it. It’s perfectly safe for floor mopping, toilet flushing, plant watering, outdoor purposes, and unless the water is hard, even showering and washing.
With such setting to use the wastewater for non-drinking purposes, RO filtration systems are now extremely efficient, with essentially zero water waste.
RO Water Use
Being one of the purest kinds of water, RO water can be employed for a wide variety of purposes.
RO water is clean and safe for consumption, especially the remineralized water. It’s free of not only toxic contaminants but also of any foul odor and taste, and has zero calories. It is the ultimate water to keep your body hydrated.
RO water is also perfect for your beloved pets, who tend to be a lot more sensitive about odors. With your dog’s sense of smell being 100,000 times better than yours, while your cat’s 10 to 40 times, there’s a real chance the water that seems fine to you smells like a public pool to them. If you’ve been giving them tap water and find them not drinking enough, RO water would be a better option.
- Skin care and hair care
If consuming contaminated water can cause skin problems, washing with them is not any better.
Your skin can be affected by all kinds of impuritants in the water: from heavy metals, which can be absorbed through the skin, to parasites, herbicides, and chloramine, which stay on it, potentially causing redness, dryness, itching, acne, inflammation, and other irritations.
The metals in hard water are also known to cause dry, brittle hair, and potentially even hair loss.
Shower filters, while very effective in removing chlorine, chloramine, and many other impuritants, can’t handle heavy metals.
That is why it is not uncommon for dermatologists to prescribe pure bottled soft water for people with skin and hair concerns.
If you have an RO filter in your home, you can have the same quality water right out of your shower head. While it can still be a bit expensive, it’s a whole lot cheaper for both you and the environment than bottled water.
If it’s hard water and/or chlorinated/chloraminated water that’s causing your skin and hair problem, you will see significant improvements within a week or two after switching to RO water. In fact, you can feel the difference immediately - most people notice the smooth, silky feeling of pure soft water on their face right after the first time.
- Washing your glasses and silverwares
Having white stains on your glasses and spoons that feel rough and won’t go away? The villain may very well be in the water you wash it with every day.
Minerals present in hard water tend to linger on all sorts of surfaces they get in contact with, including your cookwares, tablewares, and glasses. While they’re generally not harmful to your health, the stains do give the impression of a lack of hygiene.
Washing them with vinegar may help, but in the long term, it’s better to handle what causes the stains in the first place. Free of hard minerals, RO water, which is also known as soft water, is the best water to use in washing for clean, smooth and shiny appliances.
Clean water is critical to the life of your fish and other aquatic pets. Even those from hard water can still benefit from RO water, as it is free of compounds and parasites that can be deadly, or hinder the development of your fish. To make up for the minerals, use saltwater mix drops from a pet shop.
As it is soft water, RO water won’t leave stains on your fish tank, reducing the need to constantly clean it.
All that said, RO water for showering, washing, and other non-drinking purposes is an expensive choice to most people.
Ultimately, installing an RO filtration system is the best option if you want pure water, especially compared to buying bottled water. However, it’s still in no way budget-friendly. A whole-house RO filtration system costs somewhere between $2500 and $5000. Unless you have a system that incorporates the wastewater into the line for other uses, a skyrocketing water bill is also expected.
A more budget-friendly but not any less effective setting is either
- an under-sink RO filtration system combined with a whole-house simple filter,or,
- anunder-sink RO filtration system plus a water softener with a pre-filter.
We will get to why it is a better setting later. Or in fact, you can jump to that part by clicking here.
Reverse Osmosis Bottled Water vs. RO Machine
Should you get an RO filtration system, or would RO bottled water be a better choice? Let’s take a look at what each option has to offer.
- Water Purity: RO Machine 1:1 Bottled Water
There are no studies to confirm this, but theoretically, RO bottled water should be the better water in terms of purity.
Industrial machines, which have to pass rigorous tests with high hygiene standards, are supposed to take better care of the contaminants in the source water. High quality RO bottled water (and not the tap water that is simply bottled) has to go through lots of pre-filters, an RO membrane, sometimes ending with UV light for further sterilization before getting into the shell.
That said, as industrial made water is stored in plastic bottles, there is a chance that chemicals, such as oestrogen-like hormones, are leached onto it. It’s not an exception even on the BPA-free bottles.
A household RO machine, meanwhile, is typically a lot smaller in size and simpler in design. Most don’t include a UV light. The water that comes out of it is not tested for quality, unless you spend the time and money to do that by yourself.
However, if they are certified by organizations like the WQA, you can be assured the water produced is clean and safe for consumption. Then, as long as you’re drinking and storing the water in containers made of safe materials, you’re good to go.
- Cost: RO Machine 1:0 Bottled Water
An RO system can be expensive upfront.
Initially, an undersink system can easily knock $200 - $500 out of your pocket. If you’re a plumping novice, professional service may also be required, which will set you back for another couple of hundred dollars.
Now let’s see the expenses of buying bottled water.
If you are buying bottled water only for two person to drink, that’s about $0.75 for half a gallon a day, or $540 per year, or $1620 in 3 years. Why 3 years? Because that’s the lifetime of an average RO system. With the unit price + installation + maintenance + water all considered, this system can cost up to $1500.
So while you don’t get as much pure water for other needs, picking bottled water isn’t so much more expensive than installing an RO system if the purpose is to keep 2 persons hydrated. That is, without the cost to the environment taken into account.
If you have 3 persons in the household, however, the cost for bottled water is now $2430. For 4, it’s $3240. Now there’s a big difference!
At the total cost of $1500 in 3 years, with 75 gallons of water per day, the RO system can produce more than 80,000 gallons of pure water. That’s more than enough drinking water for a family of 10 people and their pets. Having sensitive/acne prone skin and needs RO water for face wash? The little under-sink system can also cover that without any extra cost.
For comparison purpose, I’ve calculated the average costs of bottled water, an under-sink RO machine, and a whole-house RO machine over a period of 3 years.
Undersink RO machine (75 GPD)
Whole-house RO machine (200 GPD)
$1.5 - $3/gallon
$200 - $500/set
$1500 - $4000/set
$0 - $250
$500 - $700
$120 - $250
$550 - $750
Total water cost (wastewater accounted)/year*
$110 - $219
$292 - $584
Average cost per 100 gallons of pure water in 3 years
$150 - $300
$1 - $3
$5.5 - $10.6
*With maximum filter capacity
Taking into account the initial cost, the installation, maintenance, and replacement cost, and all sorts of costs under the sun to run an RO under-sink water filtration system, it will still be a dirt cheap option for families compared to bottled water in the long run.
- Convenience: RO Machine 1:1 Bottled Water
When outdoors, bottled water is usually deemed the more convenient option. Taking a cool bottle out of a 7-Eleven fridge is most of the time easier than preparing your own bottle from home, especially if you’re a forgetful person.
At home, though, having running RO water is a lot better than having to store and open bottles after bottles when you need some clean water for drinking and cooking. Plus, you never have to worry about running out of stock!
- Eco-friendliness: RO Machine 1:0 Bottled Water
It’s obvious: plastic bottles are one of the earth’s worst enemies.
Here’s the ugly truth everybody knows but few want to acknowledge: If you’re drinking bottled water, you’re essentially throwing hundreds of bottles into the landfills and sea each year. That’s true even if you’re religiously putting your bottles into the plastic recycling bin - the recycling rate in the US is less than 30 percent for plastic bottles.
An RO machine, meanwhile, only uses about 2 - 4 cartridges of pre-filters per year, and a membrane replacement every 2 to 5 years. It’s a much much more environmentally sustainable way to get pure, clean water for you and your family.
Overall, if you want quality purified RO water at a more reasonable cost to both you and the environment, an RO machine is the way to go.
5-Stage Reverse Osmosis Systems
As earlier mentioned, an RO filter rarely works on its own, but usually in tandem with other pre-filters, and sometimes post-filters. The most common RO filtration setting for residential use is the 5-stage system.
This system consists of three pre-filters, a RO membrane, and a post-filter.
- First stage: Sediment filter
When raw water meets the system, it has to go through a (usually polypropylene) pre-filter. This stage takes care of the larger sediments, such as dust, sand, algae, rust, and the like in the water.
It’s typically a cartridge with a see-through shell, so you can check with your eyes and replace it if the sediments have accumulated and clogged the holes on the filter.
Since it is at the frontline, the filter gets dirty pretty fast, and may need changing more often than the others. Depending on the feed water in your house, replacement may be required every 3 to 6 months if it’s well water, or 6 to 12 months if it’s communal water.
- Second and third stage: Carbon filter
Granular-activated carbon (GAC) is typically employed in the second and the third stage of filtration in a 5-stage RO system.
With a plethora of tiny pores on its surface, activated carbon can trap a large amount of different contaminants onto its own body. Pollutants that it can handle includes chlorine, volatile organic compounds, and sediments. The medium can also improve the taste and odor of the water significantly. These filters typically need replacement after every 6 to 12 months.
On some advanced filtration systems, carbon blocks are used in place of, or together with GAC. Coming in a more solid form, the blocks are more efficient in contaminant removal, and are known to be more effective in trapping heavy metals such as lead and mercury than GAC.
These pre-filters, however, cannot completely remove tiny heavy metal molecules from the water. And that is what the RO is for.
- Fourth stage: RO membrane
The RO membrane tackles all the impuritants that are not sieved by the pre-filters: heavy metals, bacteria and viruses, hormones, herbicides and pesticides. Since the water is already very clean before this stage, an RO membrane can be effective for a long time and only needs changing every 2 to 5 years.
The rejected contaminants will then go with the wash water to the drain line, or a separate tank/pipe for non-drinking uses.
The water that passes through the RO membrane is now pure and drinkable, but for aesthetic purposes, it will have to pass the final medium before getting to the faucet.
- Fifth stage: Carbon filter
In this stage, GAV is again employed to give the water a final polish, removing any possible odor from the tank, leaving it with a pleasant taste and smell of purity. This carbon filter takes care of the already purified water, so the intervals between replacements are longer than the pre-filters, ranging 12 to 24 months.
On some advanced systems, there’s a sixth stage, where the water is further sterilized with UV light. A remineralization stage may also exist, but sometimes the minerals are incorporated directly into the system after the RO filtration stage.
Reviews of The Best Reverse Osmosis Systems 2023
Find yourself overwhelmed at the huge variety of products the market has to offer? Take a reference at our list and detailed review of the best reverse osmosis filtration systems for residential use.
Here’s our picks for the Best Reverse Osmosis Systems.
Top-rated Reverse Osmosis Systems Comparison Chart
Home Master TMAFC-ERP Artesian
200 GPD up
Stages of water procession
4 - 6
Mineral water on tap
Operating water pressure
40 - 90 psi**
40 - 125 psi
50 - 150 psi
40 - 90 psi
Pure water:waste water ratio
1:1 to 3:1
Feed water Temperature
40 - 100F
35 - 100F
40 - 105F
40 - 100F
*GPD: gallons per day (unit of water)
**psi: pounds per square inch (unit of pressure)
Designed with the inspiration from a traditional 5-stage RO system, the Home Master TMAFC-ERP-L Artesian has incorporated a few more exclusive features to boost its own efficiency and further improve the taste and smell of drinking water.
- Strong catalytic carbon filters
- Permeate pump included -> reduced water waste
- NSF-certified components
- Faucet included
- Mineralized water on tap
- High price
A Complete System
The Home Master TMAFC-ERP-L Artesian loaded package comes with everything included: the RO membrane and filters, a storage tank, a permeate pump, a nice brushed nickel faucet, a drain sandle, and all the connectors and adaptors needed.
To make it even easier, the filters are readily assembled. These filters are each incorporated into the housing as one inseparable unit. This makes changing a bliss, as you simply have to remove the whole unit and lock a new one in - there is no need to spend your time unloading the content and washing the housing when it’s time for replacement.
Installation is pretty straightforward - it should not challenge even a newbie. Some drilling may be required for the extra faucet, but that’s pretty much the most difficult part of it.
Exclusive Full Contact Technology
The Artesian loaded package offers 7 stages of water treatment: it has 2 pre-filters, an RO membrane, a post-filter, and 2 remineralization points.
Why do we only see 4 cartridges?
This is a Home Master’s patented setting. After going through the 2 pre-filters and the RO membrane where it is purified, the water will meet the Artesian filter on its way to the storage tank, and again when it travels to the faucet.
This Artesian filter, after which the whole system is named, has coconut shell-activated carbon and healthy minerals in it. The minerals are added into the pure but slightly acidic water after the RO stage to reduce acidity and prevent tank degradation. Before the water travels to the faucet, it will pass through this filter again, when any possible odor picked up from the tank will be removed.
So here are the seven stages where the water will be processed:
1. Sediment filter
2. Carbon filter
3. RO membrane
4. Carbon filter + 5. Remineralization (Artesian filter)
----- Storage tank -----
5. Carbon filter + 6. Remineralization (Artesian filter)
----- Faucet -----
With that, your drinking water will make the definition of purity.
Low wastewater rate
This loaded package comes with a permeate pump, which works to increase feed water pressure and reduce up to 80 percent of wastewater.
As a result, the drain water vs pure water ratio is lowered to 1:1 (or maximum 3:1 if you have particularly low water pressure in the home). This is extremely low for an RO system, which typically has a ratio of 5:1!
All in all, the Home Master TMAFC-ERP-L Artesian loaded package is one of the most well-rounded under-sink RO filters on the market for communal water. The price may seem higher than most others of its type, but Home Master’s smart modular filter design and the exclusive duo remineralization are totally worth it.
APEC makes some of the best (and surprisingly, also most reasonably priced) RO filters on the market, and their portable RO-CTOP is a very fine example of a quality countertop filter.
- Effective RO filter
- Easy DIY installation
- NSF-certified components
- Compact, portable
- No storage tank
- No remineralization stage
4 Stages of Filtration
The APEC countertop filter includes 4 cartridges for 4 stages of water filtration.
The first stage is a 5-micron sediment filter that takes care of the larger impuritants in the water. How small is 5 microns? To give you an idea, the human eye cannot see anything smaller than 40 microns in size.
So while it’s a “sediment” filter, it’s extremely fine and should be used for communal water only. If you’re using water from a private well, it must be processed with a pre-filter of a larger pore size beforehand, or this filter will clog up quickly.
After the first stage, the water will travel to an activated carbon filter for further removal of smaller sediments, chlorine, algae, pesticides and herbicides. It will then pass through the RO membrane, where heavy metals, hormones, and other contaminants will be washed away in a drain line. The pure water gets a final polish with a post-carbon filter before running out of the clean water line.
Sounds quite like a long and complicated journey, but the system can’t actually be any easier to install and use.
Designed to stay on the countertop, the RO-CTOP is very compact. Its four filter cartridges come readily assembled, packed together on a base. No drilling or wrenching is needed!
Yes, all the “installation” you have to do is to remove the aerator in your faucet if there is one, and connect it onto the faucet using one of the connectors included. Poof! You’re done. When you don’t need it, simply unhook it from the tap and put the whole thing into the closet.
The simple and extremely direct installation also means it’s a good choice money-wise. While the system itself is not exactly cheap, you won’t at least have to spend more money on a plumber or handyman (unless you really can’t install even the simplest machines).
Portability For The Win
The system is simple, and it doesn’t even have a storage tank, which means it only produces fresh water on demand. You hook it onto your faucet, open the faucet, and leave it there to fill your jug with pure water.
Why this instead of an under-sink RO filter?
First, if you live in a rented house or apartment and are planning to move after a few months, or indeed a year or two, the installation of a built-in system may not be worth it. Don’t want to drink and cook with contaminated water all the while? You can use this portable system, and bring it with you to the new place without a hassle. This is also the perfect choice for health-conscious students living in dormitories.
If you decide to leave it on the countertop for long, buy the version with the case for the sake of aesthetic and easy cleanup.
Crystal Quest is a name that comes to mind more often when a business needs a well-trusted water solution, but the brand actually also makes high quality RO filters for residential use.
- Effective filtration
- High pure water yield (30 - 50%)
- High customizability (can add remineralizer and UV sterilizer)
- Excellent customer support
- Requires professional installation
Super Strong Pre-filters
The Crystal Quest filtration system includes 3 filter cartridges: a sediment filter, a carbon block, a SMART filter, and of course, an RO membrane - a classic 4-stage filtration system.
What sets it apart from other whole house filters is the SMART filter. This cartridge alone has layers of micron filter pads, granulated activated carbon, catalytic carbon and an ion exchange resin. It also contains Eagle Redox alloy, a high purity copper-zinc formulation certified to remove chlorine, lead, mercury, iron, and various other contaminants from the water.
With the 2 pre-filters and a multi-functional SMART filter, the water should almost be drinkable (especially if it’s communal water) even before it travels to the RO membrane.
Therefore, the wastewater drained from this system is relatively high in quality, and should be preserved in a separate tank for non-drinking purposes (car wash, floor mopping, toilet flushing, irrigation etc). Not that the wastewater-pure water ratio is particularly high: there is a concentrate recycle valve to allow wastewater back into the feed stream and increase the system efficiency, with a recovery rate of 30 - 50%.
The Crystal Quest whole-house RO filtration system is hands down the best on the market when it comes to customization to meet the users’ exact needs.
Unlike smaller systems used in the kitchen, this whole-house filtration system can come on its own as a standalone unit. Flow rate options are available from 200 gallons per day (GPD) to 7000 GPD. Given that a person uses a total of 100 gallons per day on average for all purposes, one of somewhere between 200 and 500 GPD flow rate, and a storage tank of 165 gallons should be sufficient for a whole family.
The storage tank and the kit (the water pump), the remineralizer, and the UV sterilizers are all optional additions, which is nice since you won’t have to pay for what you don’t want/need. If you do want them, however….
A High Price for Quality Water
Each of these “accessories” can cost a fortune itself. The UV light, which would be a necessity if you’re using private well water, is worth more than 500 dollars. The remineralizer, meanwhile, wipes more than a thousand bucks off your bank account.
To top it all off, it is a large system, and installation is no piece of cake. The readily pre-assembled filters with modular cartridge designs make things a lot easier, but with electricity involved, a professional is advised by the manufacturer to ensure safety.
Even if you only get the filtration unit alone, the total initial cost with installation charge is already close to $2000. Get a storage tank, and it’s more than $3000.
The water quality no doubt justifies the cost. However, the total cost taken into consideration, this system is not exactly one of the most budget friendly out there.
Most individuals and families don’t need (and can’t afford) bottled quality water for bathing and washing your clothes and dishes. Softened tap water does just fine to most of us.
Whole-House RO Filtration System vs. Softener + Under-sink Filter Setting
A setting that is better money-wise and is also super effective is a basic filter + salt-based water softener at the point of entry, plus an RO filtration system under the sink for drinking and cooking water.
The softener removes chlorine, chloramine, metals and minerals in the water, producing soft water that is ideal for hygiene needs (showering, dish and clothes washing, etc).
The under-sink RO filter is for further removal of any harmful heavy metals, hormones, pesticides and herbicides, cysts, any remaining heavy metals, as well as the sodium used during the softening process, making the water even safer for drinking and cooking.
Mileage may vary, but you can save hundreds to thousands of dollars with this setting, compared to installing a whole-house RO filter.
If you’re extra careful still, get a shower head filter in the bathroom. All that would still cost you a thousand dollars less than a whole-house RO system alone.
To make it easier for you to imagine, we’ve compared the benefits and the costs of the two below.
For the whole-house RO system, we picked the Crystal Quest 200 GPD (the lowest flow rate available) with a storage tank of 165 gallons (the smallest tank available).
Whole House RO Filter vs. Softener + Under-sink RO Filter
Whole-house RO filtration system setting
Water softener + Under-sink RO Filter Setting
Pure RO drinking water
Soft, chlorine > chloramine-free, residue-free water for sanitary needs (showering, washing, ect)
Water wastage/person/day* (gallons)
20 - 56
1 - 3
Estimated initial cost: unit price + installation cost (USD
31xx - 35xx
21xx - 25xx
Cost for mineralized drinking water (USD)
41xx - 45xx
21xx - 25xx
Additional cost for UV sterilized drinking water(USD) **
*Given that an average person uses 80 gallons of water per day, of which 1 gallon is for drinking and cooking
**The UV sterilizer is an optional feature on the Crystal Quest. As for the under-sink system, you will switch to the Home Master HydroPerfection instead if the Artesian.
4. Best For Well Water: Home Master TMHP HydroPerfection Undersink Reverse Osmosis Syste
For a whole-house RO filtration system that takes care of well water, we again recommend the Crystal Quest system with an additional UV sterilizer to take care of any living organism in the water after the RO process. It’s a system you can’t possibly go wrong with.
- Designed to particularly take care of iron and microorganisms, among other contaminants
- High recovery rate
- Easy installation
- Mineralized water on tap
- NSF-certified components
- Requires electricity to operate (for UV light)
However, if you’re looking for the ultimate solution both efficiency-wise and budget wise, as we suggested, a softener + under-sink RO filter is the superior choice. You can take a look at our detailed buying guide for water softeners here.
In the scope of this article, we will introduce to you the best under-sink RO filter for well water: the Home Master HydroPerfection.
9 Stages of Water Treatment
The Home Master HydroPerfection offers a complete process with 7 stages of water purification, where 99% of iron, hydrogen sulfide, chloramines, chlorine, lead, dissolved solids, metals, and other contaminants are removed from your drinking water.
The water will also go through remineralization at 2 points, before the storage tank and before it travels to the faucet, where a small amount of healthy minerals are added to increase its alkalinity and give back the natural sweetness to the water.
The 9 stages include:
1. Sediment filter
2. Catalytic carbon filter + 3. KDF85 iron filter (Iron filter)
4. RO membrane
5. UV sterilization
6. Carbon filter + 7. Remineralization (Artesian filter)
----- Storage tank -----
8. Carbon filter + 9. Remineralization (Artesian filter)
That’s 2 more stages compared to the Home Master Artesian Full Contact. Let’s take a closer look at what are added and why they are important.
Iron Pre-filter + UV Sterilizer
Water from a private well is different from tap water in 2 main ways.
First, raw water, especially the water from areas suffering from drought, usually has more sediments and heavy metals (but also healthy minerals) in it compared to tap water. One of the most recognizable metals in well water is iron - a metal harmless to your health but can leave marks and traces on your sink and ceramic dishes, and clog your RO membrane. Iron is also the common culprit of that metal odor in well water.
Second, since it is usually not sanitized with chlorine, chloramine, fluoride, or other chemicals, well water is a better carrier of illness-causing pathogens.
To solve the problem, the Home Master HydroPerfection comes with a pre-filter designed to remove iron from well water before it travels to the RO membrane, protecting the membrane from possible clogging.
After the water comes out of the super efficient NSF-listed membrane, it will go through the UV light - a method of water sterilization confirmed by the EPA to be among the four most effective methods of water treatment. During this stage, any possible germs and viruses that were not rejected by the RO membrane will be destroyed.
A Well-Rounded Package with Everything Included
The Home Master HydroPerfection system includes a non-electric permeate pump that helps reduce water waste and bring the pure water-wastewater ratio to 1:1. The loaded package also comes with a water tank, fridge connection kit, and a brushed nickel pure water faucet - pretty much everything you need from an under-sink water filter.
With all the modular cartridges readily assembled and a very straightforward instruction manual, installation of the system is a bliss and can be done by yourself. If you’re not the DIY type, a casual handyman should be efficient to help.
5. Best Reverse Osmosis Bottled Water: LifeWTRPremium Purified Water
While installing a reverse osmosis filtration system is the more budget-friendly and environmentally friendly option in the long term, if you’re not in the best place to install one, RO bottled water is a great way to keep yourself hydrated.
For price, water quality, eco friendliness, and yes, coolness, we picked LifeWTR Premium Purified Water as the best RO bottled water to buy in 2023.
- Pure water, zero calories, no preservatives
- Healthy electrolytes for better taste
- Creative labels
- Relatively reasonable price
- Plastic bottles -> bad for the environment
Pure pH Balanced Water
LifeWTR is water that has been purified through an industrial-grade reverse osmosis water filtration system.
Since the water tends to be slightly acidic after purification, healthy electrolytes, including Magnesium Sulfate and Potassium Bicarbonate are added afterwards to balance it out, giving the water its natural “sweet” taste. The pH level of this bottled water is between 6.4 and 7.4.
It’s pure water at its finest: no light or heavy metals, no chlorine, chloramine, or any other chemicals. No sweeteners, colors, or any artificial flavors are added; the water contains zero calories, and no preservatives. This is the best water, under normal circumstances, to hydrate yourself with.
Designs That Spark Creativity
From a brand perspective, LifeWTR is yet another bottled water line from PepsiCo. It comes with a mission to “advancing and showcasing sources of creativity”.
The creativity is reflected through the beautiful labels, which are designed by three young emerging artists. There are new series focusing on a unique aspect in art every few months, keeping us customers inspired and intrigued every time we reach for a bottle of water.
To reduce the number of plastic bottles, we recommend buying packs with larger bottles instead of smaller ones.
Anatomy of a Reverse Osmosis Water Filter System (What Part Reverse Osmosis Water Filter System)
Reverse osmosis water filtration systems come in many different shapes and sizes, and with different components. The structure of a system may depend on the location of installation (whole house systems installed at the point of entry may have a more complicated structure than say systems installed under the sink at the point of use), the targeted contaminants (some systems may include a UV sterilizers while others may not), among other factors.
That said, there are parts that can’t be missing in an RO system.
- The reverse osmosis membrane
The reverse osmosis membrane is the most important part of an RO system.
The membrane consists of a pressure vessel with a thick semipermeable membrane on the outside, aka a membrane that allows only pure water to travel through it. This membrane is made out of dozens of thin layers of different materials, cellulose acetate and an aromatic polyamide being two of the most common. It is designed to stay strong under high water pressure, and at the same time, to reject the contaminants from entering its tiny pores.
The RO membrane has tiny pores on it to tackle the smallest molecules of chemicals and microorganisms. Because of that, it is extremely prone to clogging, and needs serious pre-filters to remove the larger contaminants in the water and protect the membrane.
Pre-filters on a typical RO system include
+ One or more sediment filters of 5 - 10 microns to remove larger sediments, rust, sand, etc from the water.
+ At least one carbon filter, which further removes sediments, light and heavy metals, algae, chlorine, as well as other chemicals.
- The storage tank
Since the RO membrane can only process a very small amount of water at a time, a storage tank serves to store the water so you always have fresh water on request. The tank usually comes as a part of the system; however, on some systems such as the Crystal Quest whole-house RO filter, it is a separate purchase and the size is customizable to your request.
After the water comes out of the RO membrane, it should be free of a majority of the contaminants, as it is of any funky odor or weird taste.
As it sits in the tank, however, the slightly acidic water may slightly wear out the tank components, and pick up odors from that. Thus, a post-filter consisting of carbon is usually employed to take care of this problem as the water travels out of the tank to the faucet.
- Installation kit
The kit should include all the tubing, stop connectors, a tank valve, faucet connectors, and a drain saddle.
RO filters are extremely effective filters. Unfortunately, they can’t distinguish between harmful contaminants and beneficial elements - they eradicate everything from the water, leaving you with a pure and slightly acidic water. While this water is safe and good enough to consume, there is space for improvement in its aesthetics.
To increase the alkalinity of the water and to boost the taste and smell, a remineralizer can be incorporated into an RO filtration system. Remineralization usually happens after post-filtration, right before the water runs to the tap. On some advanced systems like the Home Master under-sink RO filter, however, it also happens before the water travels to the tank, thus reducing tank degradation.
- UV sterilizer
For extra caution, a UV light is sometimes installed on some RO system as the final stage of water purification. UV light can kill a majority of microorganisms such as bacteria and viruses, and is very popular on systems designed for well water.
- Water pump
Household RO water filters operate in feed water with a minimum pressure of 35 psi to 50 psi. There is also always a ceiling limit of the operating pressure, but within the limit, the stronger the pressure, the more pure water a membrane can produce within a given period of time.
% Recovery = (Product Water Flow Rate/ Feed Water Flow Rate) x 100
Therefore, you can sometimes see electric pumps employed to increase the feed pressure. Non-electrical permeate pumps are also used to reduce the membrane back pressure and utilize feed pressure.
As a result, systems with a pump tend to have a higher recovery rate, or pure water- wastewater ratio than those without.
- RO Faucet
Most under-sink RO systems require an extra faucet to serve as a purified water dispenser. The faucet is most of the time included in the package.
How to Install an RO Purifier
If it’s a whole-house RO filtration system you’re planning to have, our advice is to have a professional do the installation, with consultancy from the manufacturers’ tech experts when needed. Such should be the case with the Crystal Quest introduced above, for example, the installation of which involves electric wiring and requires a licensed electrician with knowledge of the local and national electrical codes.
A countertop RO filter such as the APEC RO-CTOP-PH, meanwhile, does not require any installation other than a connection/disconnection of the feed tubing to the faucet.
Thus, we’re left with under-sink RO systems, the installation of which is difficult enough to be interesting, and easy enough to do it by yourself if you’ve been bitten by the DIY bug.
What you will need
- An RO filtration system
- Tubing and tubing cutter
- Filter wrench and adjustable wrench
- Stop connector, tank valve, faucet connector, drain saddle
- Screwdriver and drill bits
- Utility knife
- Manufacturer’s installation manual
How to do it
Make some room in the under-sink cabinet for the RO system, and prepare to see yourself working in a small cabinet for the next 30 minutes - 2 hours.
Step 1: Mount the purified water dispenser
If your sinktop already has a hole for an additional faucet, you’re good. If not, decide where you want the RO water dispenser to stay, and drill a hole of 1/2" to 1 3/8" in diameter.
Place the dispenser inside the hole and secure with a nut from under the sinktop. Attach the quick connect fitting to the bottom of the dispenser.
Step 2: Install the drain saddle
Drill a ¼” hole on the top of the drain line, far away from the drain lines of other appliances such as your dishwasher or garbage disposal to avoid cross contamination.
Place the drain saddle in and secure it with bolts.
Step 2: Install the feed valve
To install the feed valve, first turn off the water supply. Open the faucet to drain off any existing water in the tubing.
Replace the existing valve in the cold water line with the new feed valve and turn the water supply on again.
Step 3: Place the storage tank
Attach the tank valve and the tank connector. Place the tank as close to the purified water dispenser as possible to take advantage of the water pressure.
Step 4: Connect the RO system
Connect the RO filtration system to the water line, following the tubing code provided by the manufacturer.
On the Home Master system, it’s as follows:
- The orange line should be connected to the valve of the existing cold water line (or the EZ adapter)
- The black line should be connected to the RO storage tank
- The blue line should go to the quick connect fitting of the pure water dispenser
- The red line should be connected to the drain saddle
Step 5: Drain the system
Keep the tank valve off, open the RO water dispenser and wait for the water to push through the filters. Let the water run through the dispenser for about 20 minutes, until the water looks clear.
Turn the RO dispenser off, and the tank valve on. Wait about 2 -3 hours for the tank to fill. Open the dispenser and let the water run to flush the whole unit.
Repeat the flushing 3 - 4 times.
Your under-sink reverse osmosis water filtration system is now ready to serve you pure fresh water right out of the tap!
Here’s an instruction video you may find helpful:
Note: Different branches may have different color codes. Always refer to the installation manual from the manufacturer for the exact coding for your system.
How to Remove an RO System
Removing an RO system is somewhat easier than installing one.
Here’s how to disconnect and remove the Home Master under-sink RO filtration system.
What you will need
- Chlorine bleach
- Plastic food wrap
- Adjustable wrench
How to do it
Step 1: Turn off the feed water supply to the RO unit, and turn on the pure water dispenser to drain the system. Wait until there’s no more water coming out of the dispenser.
Step 2: Remove the black line from the storage tank, and turn the dispenser off.
Step 3: Turn the tank cap and close the tank valve. Spray the bleach to the opening of the black line and the tank valve port and wrap them in plastic food wrap to prevent contamination.
Step 4: Remove the orange line and the red line. Drain any remaining water. Repeat the same anti-contamination method mentioned on Step 3.
Step 5: Remove the purified water dispenser.
Again, the color codes may be different on RO filtration systems from other brands. However, you can still dismount your system following the same steps.
About your guide
Luna Regina is an accomplished writer and author who dedicates her career to empowering home cooks and making cooking effortless for everyone. She is the founder of HealthyKitchen101.com and HealthyRecipes101.com, where she works with her team to develop easy, nutritious recipes and help aspiring cooks choose the right kitchen appliances.