- 1 Introduction to Reverse Osmosis Filtration
- 2 Best Reverse Osmosis Water Filter System Reviews:
- 3 A Guide to Help Choose The Best Reverse Osmosis System
- 3.1 Reverse Osmosis Filtering Systems Explained:
- 3.2 Principles of Reverse Osmosis:
- 3.3 Reverse Osmosis Filters and how they work:
- 3.4 A Step-by-Step Explanation of Reverse Osmosis Filtration:
- 3.5 Some Reverse Osmosis FAQ:
- 3.5.1 Do Reverse Osmosis Systems Require Electricity?
- 3.5.2 Will I need a pressure booster pump?
- 3.5.3 Do I need a permeate pump?
- 3.5.4 How Much Water Does Reverse Osmosis Waste?
- 3.5.5 Should I go with a Whole-House Filter or a Point of Use Filter?
- 3.5.6 What do Point of Use Reverse Osmosis Systems include?
- 3.5.7 How much filtered water will my RO System produce each day?
- 3.5.8 How long will my filters last?
- 4 What Contaminants are Removed by Reverse Osmosis Systems?
- 5 Sources Cited
Introduction to Reverse Osmosis Filtration
Reverse osmosis filtration systems are arguably one of the best and most popular options available to the homeowner as a method of providing your family with clean, fresh water. Known for their efficacy, their multi-stage filtration technology enables these systems to remove up to 99% of certain toxins and contaminants from the water (e.g. fluoride, radionuclides, arsenic, uranium, radium, nitrate, etc) 1, and depending on the source, anywhere from 85% - 95% or more of other contaminants.2
On this page, we'll introduce you to the best reverse osmosis (RO) water filters and systems that we have found (updated for 2019). As with any system, there are different pros and cons which may affect your decision, depending on your primary concerns. We'll talk about what these systems can and cannot remove as well! For example, while this method can remove arsenic and fluoride, it cannot remove radon gas or hydrogen sulfide ("rotten egg" smell) on its own (both require filtration, and in the case of radon, aeration to keep it from getting into the air in your home).
Don't worry if you don't have a full understanding about reverse osmosis water filters yet. We'll explain things in a way that will clarify the different steps in this process so that as consider the best option for you and your family, it won't feel so overwhelming!
One of the things consumers seem to agree with over and over is that on the whole, these units are not difficult to install or maintain. Yes, you do need to switch out filters once in a while, but this is the case with nearly any type of unit.
As you begin reviewing the option for your own needs, please remember that the best starting place is to ensure that what you are trying to get rid of in your water can be removed to begin with.
Since you probably want to have a look at some systems right away, let's jump in.
There's lots more reading about each individual product further on down this page below these initial previews!
Click any of the images to visit that product page!
Water Production: 66 Gallons/Day
Filtration: 4 Stages (Including UV)
Price Point: Between $450-$500 (Financing Avail)
Water Production: 75 Gallons/Day
Filtration: 9 Stages (Including UV & Re-mineralization)
Price Point: Between $400-$450
Water Production: 75 Gallons/Day
Filtration: 5 Stages (Including UV)
Price Point: Between $200-$300
Water Production: 75 Gallons/Day
Filtration: 6 Stages
Price Point: Between $200- $300
Water Production: Up to 100 Gallons/Day
Filtration: 11 Stages (Including UV)
- For 10-Stage, Approx $200-$300
- For 11-Stage, Approx $300-$400
Water Production: Approx 3 Gallons/Hour (75/Day)
Filtration: 5 Stages
Price Point: Between $100-$200
Water Production: Approx 50 Gallons/Day
Filtration: 4 Stages
Price Point: Between $300-$400
Best Reverse Osmosis Water Filter System Reviews:
AquaOx Reverse Osmosis
Topping off our list of the best reverse osmosis filtration systems is AquaOx’s Reverse Osmosis (RO) Kitchen Sink Drinking Water System. The AquaOx system is engineered to eliminate the toughest contaminants. Its four inline filters are geared up to remove things like unwanted sediment, carcinogens, heavy metals, tastes, odors, and more.
This unit is among one of the easiest to install, and maintenance couldn’t get much easier either. The filters are part of a proprietary quick-change system. Of course, replacements are only needed roughly once a year or after 2,500 gallons of use. The user-friendly replacement system should keep you from postponing the process.
The AquaOx is capable of producing up to 30.65 gallons of purified water per day. It has a flow rate of 0.5 gallons per min, which is pretty nice because the filters boast 5-micron ratings. This product also has an efficiency rating of just over 1-to-3. This is ideal for a RO filtration system without a permeate pump.
The AquaOx does have some pretty specific feed water demands. As such, this unit should only ever be used with already potable tap water.
The unit is well-built and reliable. Those that find the price too steep are free to explore the third-party financing options offered on the product website.
We just love the fact that AquaOx is a veteran-owned and -operated company. Their mission is clear. It’s to eliminate water quality issues while producing the best possible H20 for your home.
Over the years, this and AquaOx’s other filters have earned rave reviews from critics. Click here to learn even more about the AquaOx Ro Kitchen Sink System.
Home Master - (Model "TMHP-L HydroPerfection") RO System
As of this writing, the TMHP-L HydroPerfection model of Home Master's Undersink - or, what is also termed "Below the Counter" option is getting accolades for being one of the best RO systems available currently (right now we are in the 2nd half of 2021).
Now, it's important to note that their TMULTRA-ERP Ultra Undersink system also has great reviews; however, it appears that with the additional feature of the Remineralization stage on the TMHP-L HydroPerfection, this one is the clear winner for Home Master in our opinion.
[IMPORTANT NOTE: We still believe that the TMULTRA-ERP is a great choice, and would like to direct your attention to a special review we've included. CLICK HERE to learn more about the TMULTRA-ERP so that you can compare it to this model.]
Like the other model, the TMHP also shares the same 1:1 efficiency ratio as the TMULTRA-ERP, which means that you'll only have about 1 gallon of waste water per 1 gallon of filtered water. One of the reasons for the low waste to filtered ratio is their permeate pump (included), which helps lessen the amount of waste. In many regions where water usage is a concern, this is an important point.
In addition to the permeate pump, this system includes a UV light for further purification. This means that you will need electricity to run this unit.
With the HydroPerfection system, you will have plenty of water each day because it produces up to 75 gallons on a daily basis (75 Gallons/Day is pretty good)!
We mention that this model comes with the UV filter, which many consumers prefer due to its ability to kill off microorganisms, bacteria and viruses that somehow make it through the RO membrane.
Couple that with long lasting and easy-to-change filters that only need to be changed once a year (or every 2,000 gallons or so), highly rated customer service, AND the re-mineralization filter that adds back important levels of calcium and magnesium (approximately 30-60 mg/l combined), and we have a winner! See the TMHP-L HyrdoPerfection Here!
We wanted to compare apples to apples, by placing the iSpring RCC7AK-UV directly next to the Home Master TMHP HydroPerfection unit that you just read about. Again, we have a top-notch reverse osmosis system, that also has the re-mineralization option along with the UV option. As far as price is concerned, this may very well be your go-to choice given that its cost is approximately $150 less than the TMHP.
In this case, the RCC7AK-UV seems to do a bit better in customer reviews than its sister unit, the RCC1UP-AK (which shares similar qualities).
In this model, however, there is no permeate pump, so its efficiency ratio is just a touch lower that the Home Master. In this case, the ratio is 2:1, but still produces a good volume of water, at 75 GPD.
Because it has the UV aspect, the unit does use electricity. It is an energy conscious choice, because the UV only turns on when there is detectable water flow, and then it automatically shuts off once the flow stops (actually, once the water flows through and into the pressurized storage tank).
This system works great if your incoming water flow is 45 PSI - 70 PSI. (NOTE: If you are looking for a system that also has a booster pump [helpful if your home's water pressure is too low to run the system naturally] check out the RCC1UP-AK model, also by iSpring - their 7-Stage Maximum Performance 100 GPD model.)
The company claims that its pre-installed Phillip UV lamp will kill 99% of any bacteria making it past the RO membrane.
This model does have the cartridge to add back calcium and magnesium, which many people say improves the overall taste of what ultimately comes out of the faucet.
We decided that there is quite a bit more to say about this excellent choice, and so we have included a more in-depth review of the iSpring - and have also included a closer comparison between this and the Home Master. CLICK HERE to learn more.
APEC ROES-PH75 ESSENCE 6-Stage
APEC's model (that includes the "ESSENCE" designation, along with the model "ROES-PH75") is another highly rated unit that includes the alkaline re-mineralization option. On Amazon, it is also titled "Top Tier" along with "Alkaline Mineral pH+" and boasts a high quality, 6-Stage system. You can expect a nice 75 GPD production with this 6-Stage system (if your home water pressure is about 60 psi). This appears to be a good choice for over 700 consumers who have given this model high marks. And coming in at well under $300 it is a good value.
Because this one does not have the UV filter or a booster pump, there is no need for an electrical hookup. As long as your feed water pressure is anywhere from about 40 psi - 85 psi, you're good to go! For consumers desiring the UV filtration option, APEC does offer their 7-stage model, ROES-PHUV75, which includes the UV light sanitizer for less than $100 more than this ROES-PH75 model.
There aren't many manufacturers of these home units that seem to respond quickly to customer reviews, but these folks do. Whenever there is a negative review (and there aren't very many at all) APEC responds, and in every case is willing to work further with the customer to see what may have gone wrong. We like that.
They advertise that their efficiency ratio is about a 1:3 ratio (this means that producing 1 gallon of filtered water will result in approximately 3 gallons in waste/drain water). Considering that there is no permeate pump on this model, that efficiency ratio is pretty good.
Express Alkaline UV 11-Stage
We've touched on a few of the more well-known models that use 6 or 7 stages of filtration. Now let's have a look at the Express Water Reverse Osmosis, 10 and 11 Stage units.
This company and its systems is worth an entry on this site for its attention-grabbing confidence. First, let us clarify the primary difference between the ROALKUV10DCG model, and another one of their popular models, ROALK10DCG.
The Express Water ROALK10DCG is a 10 Stage RO Mineralizing Water Filter (with Mineral, pH + Antioxidant filters), and is an under sink/under counter unit with the remineralization option. This gives you 100 GDP. The filter housings are clear so that you can visually inspect the filters inside each housing.
The Express Water ROALKUV10DCG is an 11 Stage purifier that includes a UV purifier. It's the same as the 10 Stage, only with the Ultraviolet sterilizer stage added, making it an 11 stage system. Again, you have clear housings. See an image of the 11 Stage model above.
Their 10 stage system works as follows:
Stage 1: Their 1st stage is a sediment filter,
Stages 2-3: their 2nd and 3rd stages include a carbon block filter, and then a GAC (granular carbon) filter,
Stage 4: followed by the RO Membrane for the 4th stage.
Stages 5 - 9: Stages 5, 6, 7, 8, and 9 re-mineralize the water, and add antioxidants and oxygen. You won't see 5 separate filters for those stages however, because they are combined in a single cartridge as illustrated in the picture below.
Stage 10: The 10th stage is the final activated carbon filter.
In the 11 stage system, it works the same way, except that the 10th stage is the UV sterilization, followed by the final activated carbon for the 11th stage.
Customers report ease of installation and the fact that the color-coded system helps.
The idea of the 5-stage mineralization option to add potassium, calcium, and magnesium to the water sounds like a good idea. Some customers like it, others didn't seem so keen on it. One reviewer didn't care for it, and disconnected that particular filter and was pleased with the flavor of the water afterwards. This appears to be a personal preference.
The price for either option seems reasonable - under $200 for the 10 Stage model, and under $300 for the 11 Stage model. One thing to keep in mind is that it appears that the UV light stays on all the time, which may be a consideration for some.
Reverse Osmosis Revolution Portable/Countertop
Thus far we have concentrated on reviewing the under sink models, but the Reverse Osmosis Revolution Countertop 5-Stage Portable unit is definitely worth a mention here! Coming in at only about $130, this is definitely a contender for many folks who might otherwise be unable to install a full under sink system (e.g. renters, RV-ers, etc).
And it's a brilliant idea. Why aren't more companies offering this option? And the customers who have purchased this agree. By all accounts, set-up is simple and fast. Yes, this type of portable unit is going to take quite a while to produce your drinking water. That's to be expected, but for a temporary or portable/countertop RO system, it is exactly what it needs to be.
The literature says that you can expect the system to make anywhere from 500 - 700 gallons before you need to replace the filters. The way my household filters drinking water, that is about 3-4 gallons per day (drinking water), so if we divide an average of 600 gallons by 4 gallons, that's about 150 days, or about 5 months. Considering we might spend $4 per day on cheap bottled spring water, that's about $600 in 5 months (or $120 per month). The entire system is less than $150! And replacement filters are less than $100.
It would be great if they could add a re-mineralization stage! (Reverse Osmosis Revolution folks, can you hear me?) Nonetheless, customers state that if you desire the addition of minerals, that there are numerous products on the market for that purpose.
So the literature also says that it takes about 1 hour to produce 3 gallons. That sounds like a bargain to me. See it on Amazon here.
A Guide to Help Choose The Best Reverse Osmosis System
Whether you are looking to install a portable or a built-in system, we know you’ll have questions. Some of the more common questions we get are not only what are the BEST systems, but also: Which are the most efficient systems? Which ones are best “under the sink” models? How about the “whole house” models?
And, now that you’ve seen a few top-rated RO systems and what some of them offer, you may begin to wonder if you need “just a little” bit of filtering, “a WHOLE LOT of filtering,” or if you need to use UV light or add minerals.
Reverse Osmosis Filtering Systems Explained:
In simple terms, a Reverse Osmosis System (aka RO), is a method designed to force water through a series of semipermeable membranes that have microscopic pores designed to keep the unwanted substances behind, allowing only the clean water through.
The way this is accomplished is that the pores in the membrane are so small, that the contaminants whose particles are larger than the water particles simply cannot pass through. Naturally, the result will be tastier and cleaner water on the “other side” of the RO membrane!
It isn’t just homeowners like us who love this type of system. It is exceptional for treating water in a variety of industrial settings as well. More and more farmers are using it in their operations (it is also popular in hydroponic farming). In addition, breweries love it because it means a higher quality water for their beers – and higher quality water means a higher quality, better tasting beer. The same goes for restaurants and coffee houses. It is used in desalinization plants. The military has even developed a portable RO system that can not only be used in the field, but also for disaster recovery, such as the Water Assessment and Purification Toolkit or WAsP. 3 The use for RO systems is endless.
Principles of Reverse Osmosis:
Let’s first look at the principle of osmosis to begin with. We experience osmosis every day since it is a totally natural process in our lives!
Most scientific explanations of osmosis refer to a “solvent” of a lesser concentration being moved through a semi-permeable membrane into a more concentrated solution. A “solvent” is something that can dissolve another substance; therefore, water is a solvent since it can dissolve another material.
For example, water can dissolve salt or sugar.
So, let’s use the example of salt water for our explanation. In osmosis, you have two solutions separated by the “semi-permeable” membrane: On one side is a less concentrated (less salty) liquid, and on the other side is a more concentrated (more salty) liquid.
In osmosis, what will happen is that the less concentrated (less salty) water naturally wants to move toward the more concentrated (more salty) water because it wants to create an equilibrium between the two sides.
Using another example: our own bodies! If you are dehydrated, your cells shrink from lack of water – and your cells would be the “more concentrated side” of the equation. When you drink water, it is naturally delivered to your water-starved cells through the semi-permeable membrane of the cell until the equilibrium is achieved.
Now, you may ask, “But what if I don’t WANT the water to be salty?” THAT is where REVERSE Osmosis comes in. It takes the process we just illustrated and REVERSES it. So, in the case of the salty water example, instead of the less salty water migrating to the more salty water, we exert a force on the salty solution and move it through the membrane to keep the salt particles BEHIND, resulting in clear water on the other side of the membrane.
Remember that in a real life situation, there are going to be different particles that we want to remove from our drinking water, and the system that you choose will have the filters and the semipermeable membranes designed for those purposes. So let’s have a look at these filters and how they work.
Reverse Osmosis Filters and how they work:
As we just illustrated, the general way in which reverse osmosis filters work is that the water containing the undesirable particles is forced through a semi-permeable membrane. As it does this:
- The reverse osmosis membrane’s pores (which are very, very small) blocks the vast majority of the particles (estimates are that anywhere from 95% – 99% of contaminates can be removed via RO)…
- These blocked particles are considered waste (wastewater) and are discarded and drained away (the technical term for this is “reject water” or “concentrate water”).
- This concentrate is “rinsed away” with more water. In some systems, this wastewater can be recycled; although for homeowner use, it is more likely to simply be discarded unless the consumer desires to use it for purposes where filtered water is not required.
You are probably wondering how much pressure is needed to move this water. It’s a good question, and the answer is, “it depends,” because water with less contaminants will not need as much pressure as water with higher levels of contaminants.
The technical name of the water that comes through “the other side” of the filters is “permeate” water in scientific and industrial terminology; however, as a homeowner, you can simply call it “filtered” (in some cases you may hear it referred to as “pure” water; however, it should be noted that NO filtration system will remove 100% of particles).
How the “Reject Water” Is Separated from “Permeate Water”
Unlike other systems (where the filters themselves collect or absorb the undesirable particles), with reverse osmosis, one “outlet” is necessary to get rid of the “reject water,” and another “outlet” is necessary to carry the clean, filtered water to a tank or its point of use. This setup is called “cross filtration.”
Cross filtration also accomplishes another task; and that is to keep the semipermeable membrane clean so the contaminants that are left behind don’t clog up the membrane. Consumers still need to replace filters occasionally, but not nearly as much as they would be if the contaminants were left in the system.
A Step-by-Step Explanation of Reverse Osmosis Filtration:
While some RO systems have fewer stages than others (we’re seeing anywhere from 3 stages to 11 stages), we’ll outline the steps in one that uses more so that you can get an overview of a larger system. When you investigate the various options available to you, you’ll see the number of stages/steps each system offers right up front (e.g. “Home Master 6-Stage TM ULTRA-ERP,” the “APEC ROES PH75 6 Stage” model, the “iSpring RCC7AK-UV Deluxe Under Sink 7-Stage” unit, or the 11-Stage “Express Water Alkaline Ultraviolet” model.)
You may not need an 11-Stage or even a 7-Stage system, depending on your reasons for opting for RO to begin with. If you don’t have many contaminants in your water, you may be completely fine with a 3-Stage system! If you want to remove a number of compounds such as fluoride, lead, chlorine, arsenic, etc, you may opt for a system with multiple stages. No matter how many “stages” are in each system, they will share a few commonalities – especially when it comes to the reverse osmosis semi-permeable membrane itself.
Generally speaking, all reverse osmosis systems are going to have a “pre-filter” for sediment, followed by one or more pre-carbon filters, then the semipermeable reverse osmosis membrane filter (or filters), another, “post-carbon” filter, and in some cases, an alkaline remineralization option (since RO removes the minerals from water) and even a UV sterilizing option in some.
The General Steps/Stages of a Reverse Osmosis System:
- 1st Step/Stage: Pre-Filter (Sediment Filter) – In this stage, the feed water passes through a sediment filter designed to remove larger particles such as rust, dirt, or silt that may be in in the feed. It’s important to remove these particles before they get to the RO membrane – there is no need to put these larger impurities through a membrane when a simple sediment filter can take care of them immediately (and thereby saving unnecessary wear and tear on your membrane and the system overall).
- 2nd Step/Stage: Pre-Filter (Carbon Filters – can encompass several stages in this step) – There may be more than one carbon filter in this stage. In systems that include 2 carbon filters, for example, then this would be considered 2 separate stages. In systems that include 3 of these filters, each of these is a separate stage. As the water passes through the “pre-carbon” stage, chemical tastes and odors (such as chlorine) will be removed, as will a number of other organic contaminants, or VOCs (Volatile Organic Chemicals). In systems where there are more than 1 carbon pre-filter, you are likely to see both Granulated Activated Carbon (GAC) and Carbon Block (CTO) as the media.
- 3rd Step/Stage: Reverse Osmosis Membrane – This is where the RO magic happens! The water is now pushed, under pressure, through the semipermeable membrane, which blocks up to 95%-99% of the smallest particles in the water, allowing only fresh, clean water to filter through. THIS is where you’ll get rid of the fluoride, radionuclides, lead, etc.
- 4th Step/Stage: Post-Carbon/Additional Carbon Filtering (“polishing”) – Once the water has passed through the reverse osmosis membrane, it continues through another carbon filter (usually made from coconut shell) to ensure that any remaining odors and residual particulates are removed.
- 5th Step/Stage: Ultraviolet (UV) Light Treatment (Optional) – Used to ensure that any residual bacteria or other microorganisms that somehow makes it through the RO membrane is eradicated. Note that this stage is not used as frequently, and there are mixed opinions as to whether or not to include them. Some of the arguments against adding UV is that it takes electricity to run, the heat from the light can cause the components under the sink to weaken or otherwise become brittle, or the water may come out hot. While most consumers don’t opt for this particular stage, some do, and therefore a number of manufacturers offer systems that include a UV sterilization stage.
- 6th Step/Stage (up to even 11 Stage): Remineralization (also Optional) – At this point in the process, pretty much all the minerals have been removed from the water (approximately 95%), including those which some people DO want (e.g. calcium). Also, some people don’t particularly care for the taste of demineralized water, saying that it tastes “flat” or “bland” (also a common complaint about drinking distilled water). This is where the “remineralization” comes in. In some units, a filter does the trick to replace some of the calcium. You can see in numerous highly-rated and best-selling RO systems featured here on the site, this stage is added. For example, with the iSpring RCC7AK product, after water passes through the first 5 stages of the system, there is an additional stage called the “Alkaline Remineralization (AK) stage.” So, if mineral depletion is a concern, this additional stage can be helpful.
Do Reverse Osmosis Systems Require Electricity?
On their own, household RO units do not require electricity since it is the pressure of the water itself that moves it through the system. However, if the system you are using includes a pressure booster pump, or a UV sterilization stage, then you will need electricity. If the water coming into your home doesn’t have enough pressure on its own, chances are you would need a pump (see next question). Reverse osmosis systems used for industrial purposes use pumps, and therefore, those would need electricity to run.
Will I need a pressure booster pump?
Because these systems depend on pressure to work, if your household water pressure isn’t high enough, you will need a pump. According to iSpring, which manufactures some of the highest rated reverse osmosis water filtration systems on Amazon, if your pressure is less than 45 psi, the system cannot work. If your water comes in at 60 psi (which they say is fairly typical for most city water supplies), you should be fine. One of iSpring’s higher end units states that their system runs best at 80 psi, which is what their own pressure boost pump supplies.
Do I need a permeate pump?
You may not need to use a permeate pump if your system fills quickly enough to suit your needs. Some manufacturers say that a permeate pump can reduce the waste water by up to 80%, while increasing the efficiency of your RO system tank’s fill time by 65%. You do not need electricity to use a permeate pump since it runs on the pressure in the system. A lot of people DO opt to have a system that uses a pump since they would prefer a slightly more water-saving option. In some of the reviews of systems above, you can see that a few of them come with the pump. Check out this short video that shows how a common permeate pump is installed.
How Much Water Does Reverse Osmosis Waste?
This is one of the most common questions with regard to RO, and understandably so since water that is used to wash the impurities from the membrane goes down the drain (unless it is collected and recycled). However, it is important to understand that the process of reverse osmosis USES water to “flush” away the debris and contaminants left behind so that these residuals don’t harm or plug up the membrane. Think of a toilet flushing waste away – and for the most part, we certainly don’t think of the toilet as “wasting” water. With reverse osmosis, the water that is used to wash away the residual impurities only runs when the system itself is in operation. So, once your system has filled the pressure tank, it stops running – and of course, so does the water.
There is another thing to consider when we think about “waste.” Did you know that numerous brands of bottled water are also produced by Reverse Osmosis? Check the labels at the store and you’ll often see the method used to purify it. So, even you feel that you might just go back to bottled water, not only might you be purchasing filtered water produced via RO (which will also have used water to clean and clear the membranes at an industrial level), but you will be going right back to using plastic bottles (which is another problem altogether).
Should I go with a Whole-House Filter or a Point of Use Filter?
The answer to this depends on a number of factors. Are your clothes getting discolored in the wash? Is there iron or other metallic residue in your tub/shower/sink? Does the water smell foul throughout the system? How much water does your household use? Also, consider the “waste water” factor – if you honestly don’t think you need an whole house filtration system, you will see less water waste using an under counter reverse osmosis water system. However, if your water supply affects your quality of life in every aspect of your day to day existence, you may want to consider treating your water at the point of entry to alleviate all concerns.
What do Point of Use Reverse Osmosis Systems include?
Most systems will come to you complete with all the filters and membranes, the tubing, pressurized storage tank (which will hold the filtered water – aka permeate), You will notice that with a lot of these under sink models, there is an additional, dispensing faucet on the countertop. That is because when installing an RO system for cooking and drinking water, there is no need to put all your water – for example, water you’re going to use to wash dishes – through the system, so the smaller tap is installed to specifically deliver only what was filtered. The exception would be a countertop reverse osmosis system such as the one we featured above, which is a portable unit and therefore would not have a pressure tank to store the filtered water.
How much filtered water will my RO System produce each day?
Each system is different. In our comparison chart and reviews, we include the metric of “gallons per day” or “GPD” reported by each manufacturer. Some advertise 50 GPD while others state 75 GPD, 100 GPD, etc. Related to this question is “water flow” or output at the faucet, which will also depend on whether you are using a pressure tank or not. For example, if you are not using a pressure tank, the flow from the system to the tap will be slower than if the tap was being fed from the pressure tank.
How long will my filters last?
Reverse osmosis systems are quite simple to maintain. And each manufacturer will give you an estimate of when you should change the filters.
Of course it depends largely on each system as well. In our review of the Reverse Osmosis Revolution’s PORTABLE, countertop unit, they estimate that their filters will last about 500-700 gallons. This is considerably different from a more permanently installed system.
For example, take a look at this illustration from iSpring, which shows you about how long each of the filters in their iSpring RCC1UP-AK 7-Stage Maximum Performance 100 GPD system will last. No matter which system you use, it’s a given that you will be saving a lot of money over continued purchases of bottled water.
What Contaminants are Removed by Reverse Osmosis Systems?
This is one of the reasons why this method of filtration is so highly recommended by the CDC. Depending on the system, you can reasonably expect to see a 95% – 99.99% reduction in contaminants. Some systems claim that they remove up to 1,000 different substances. We have created this page that discusses the basics of what each main type of filtration option removes. We’ll go into a little more depth here.
As far as what the RO membrane itself is able to remove, it may be helpful to realize that the pores are so tiny that anything larger than 0.0001 microns is likely to be blocked! If you consider that an average human hair measures about 50 microns, you can understand why the reverse osmosis process is so effective!