Planning to buy a reverse osmosis water filter system for your home?
There are so many different models on the market, right? A confusing choice of brands with prices from $150 to way over $600.
So, which is the best home reverse osmosis filter to purify your tap water?
Let me help you to make the best choice. I will explain the manufacturers’ lingo and have a list of points you should pay attention to in my RO filter system buyer’s guide further down.
Let’s start our tour with a comparison of some of the best budget under sink models.
3 Best Budget Reverse Osmosis Filter Systems
The best budget reverse osmosis filter systems have 4 or 5 filtration stages. The lower price does not mean you have to compromise on filtration ability. The difference is mainly in capacity. The models I selected here all use 50 GDP (gallons per day) membranes.
Now, let's take a closer look at my favourite budget RO systems.
Apec Essence ROES-50
The Apec Essence ROES-50 Apec's basic 5-stage filtration system and the successor of the equally successful Apec RO-45.
Although not certified, many owners wrote very positive reviews. They praise the easy installation and maintenance. And the helpful customer support.
The filter change interval is similar to the one of the Watts Premier RO-Pure. To own and run the Apec Essence ROES-50 for five years you will spent around $609.
The Apec Essence wastes a bit less water than the Watts system. In the long run, this is good for the environment and your budget.
On the negative side you have a small tank. And that you have to buy o-rings for filter replacements separately is something I truly don't understand.
All in all, this is the right system for you if you want a better than average waste water ratio.
Need some more details? Here is a longer review of the Apec Essence ROES-50.
Watts Premier RO-Pure 531411
The Watts Premier RO-Pure is a 4-stage RO system with great, certified reduction rates. A lot of though went into the design and installation instructions to make it as easy as possible.
Other advantages of the Watts Premier RO-Pure are the included air gap faucet and an electronic filter change indicator. The filter change indicator is something even more expensive systems don't have. I am not surprised that Watts has so many positive reviews.
The pre-filters usually last around 6 months, the post filter even a year. The membrane is good for 2 - 3 years. Replacement filters do not cost that much and are available in even cheaper packs. Buying and using this system for 5 years would cost you only $559.
Are there any downsides? Sure, the small tank, typical for budget systems, is one of them. The other one is the waste water ratio. The Apec Essence scores a bit better here.
The Watts Premier RO-Pure is the best budget reverse osmosis system for you if you want a certified system with air gap faucet and a filter change indicator.
Olympia Water Systems OROS-50
The Olympia Water Systems OROS-50 is BPA and lead-free 5-stage reverse osmosis filter. You can only use it with tap water, but that is standard for budget RO filters.
After the water passes through a sediment Polypropylene filter, two 5 micron carbon block filters take out bad taste and odor. The next filtration step is a 50 GDP thin film membrane, before it enters the 3.2 gallons tank.
When you open the faucet, the water passes another carbon filter. Olympia Water Systems does not offer any alternative faucets. The included one has a swivel-sprout, chrome-finish and comes with a ceramic disc valve.
Frequent filter changes are necessary every 6 months. Assuming you use this system for five years, you would have to spent estimated $664 for the system and new filters. That is a very competitive price.
This system is certified by NSF, something you do not find often in budget systems. It passed tests to NSF/ANSI standards 42 and 58.
This system is for you, if you are on a budget and don't need an air gap faucet.
Best High Capacity Reverse Osmosis Water Filters
Home Master TM-ERP-L - Faster water flow
The Home Master TM-ERP-L is a 4-stage system with a 75 gdp membrane, ideal if you need more clean water or for hard water areas. The filters last 1 year or 3900 gallons, so you have less work changing them.
The whole system is designed and built in the USA. Home Master is very confident in their quality and grants you an exceptional long warranty of 5 years. That is 4 more years than what you get from most other brands.
A permeate pump comes with the system. It improves the waste water ratio so you waste just 1 gallon per 1 gallon clean water. I haven't seen a system with a better ratio, yet. And this pump does not need electricity.
Another highlight is the fast flow kit. It helps to increase the flow between tank and faucet. As a result, filling a pitcher with water takes less time than with other systems.
What I don't like so much is the small tank they added to this package. And if certification is important to you, some of the components are. Unfortunately Home Master is not very clear which ones.
This system is ideal for you if you don't want to waste water. The long warranty and other features are just the top of the cake.
The iSpring RCC7 is a WQA certified 5-stage filtration system. The sediment filter is in a clear housing, so you can easily see when it is time to change. An easy solution, and helpful if your water contains a lot of sediment.
It has the lowest list price of the three compared filtration units here. Customers left a lot of positive reviews on amazon, especially after the manufacturer improved the system in 2014. Many of them like the amazing value for money.
The pre-filters don't last as long as the ones in the Home Master TM-ERP-L, so a bit more work involved here. With the frequent filter changes, the filter price does matter. If you do not find filter packs on offer, the iSpring is more expensive to run than the Home Master.
If you don't mind to hunt for filter bargains and certification is important to you, this is your best best choice.
Apec Ultimate RO-90
The Apec Ultimate RO-90 is part of Apec's high end model line with a 90 GPD membrane. It come with 5 filtration stages with an average waste water ratio of 3 gallons wasted per 1 gallon clean water.
One thing I especially like is the certification not only for the system integrity, but for unhealthy contaminants like radium and a few others. So you can be sure, this filter does what it is supposed to do - take them out of your water.
The post filter lasts even longer than the one in the Home Master. If they had chosen to add a larger tank to the system, it would be perfect.
It is the ideal system if you want certified reduction of any of these nasty things: Barium, Cadmium, Copper, Fluoride, Hexavalent Chromium, Lead, Arsenic (V) (less than 50 ppb reduction), Radium 226/228, Selenium, TDS, Trivalent Chromium, Turbidity.
Best Alkaline Reverse Osmosis Filters
All top 3 high capacity filters I reviewed here are also available with a mineral or alkaline filter. They share the same features and are more expensive.
Home Master TMAFC-ERP-L - Fewer filter changes
The Home Master TMAFC-ERP-L is an alkaline RO system with the lowest waste water ratio.
Two features set it apart from the others reviewed here. A permeate pump which does not need electricity is included as well as a fast flow kit. You get more water faster from the faucet.
The only difference to the Home Master TM-ERP-L is the 4th stage mineral filter. The cost for system and filters for 5 years is around $779. You will get the same 5-year warranty and only have to change 3 filters per year. That means minimum maintenance.
Included in this special package is also a brushed nickel faucet and a kit to connect the system to your refrigerator.
What I like about this system is the long filter life. Even the mineral filter last 1 year. Other systems require a change every 6 months. Plus the water passes this mineral filter twice. So the water that enters your tank is no longer acidic and the tank lasts longer .
Ideal for all who prefer to deal with maintenance and filter changes only once a year. Plus it wastes very little water.
iSpring RCC7PH - lowest Price
The iSpring RCC7PH shares all the great features of the RCC7. On top of that, the cost for system and filters over a span of 5 years is the lowest. That is due to low cost of replacement filter packs especially for this system.
This is the most budget friendly of all compared alkaline RO systems.
Apec Ultimate RO-PH90
The Apec Ultimate RO-PH90 is the alkaline version of their a certified system. The 90 gpd membrane can filter more water that the two other systems here.
Owning this system is a bit more expensive. I used only list prices for my calculations. So there is a high chance that you are able to find cheaper replacement filters online.
Recommended for medium or large families who want certified removal rates.
Looking for the best counter top reverse osmosis water filters? I compared them in a separate post.
How does reverse osmosis (RO) water filtration work?
Reverse osmosis is basically a hyper filtration process. It uses pressure to force the water through a membrane. The RO membrane works as a filter for extremely small particles. While an average activated carbon filter holds back particles larger than 5 microns, a reverse osmosis membrane stops particles larger than 0.0001 – 0.001 microns.
Most pesticides, herbicides and metal ions – to name just a few contaminants – are larger and can not pass through the membrane. They get flushed out with the waste water. And they never reach the tank storing the purified water.
How a reverse osmosis unit performs at your home depends on a few factors.
First, the the quality of the membrane and other filters in your system is important. But apart from that, water temperature, water pressure, incoming water quality and total dissolved solids (TDS) can also influence the performance of a RO water filter.
What are the main components of a reverse osmosis system?
The pre-filters serve a triple purpose. They are the first barrier for rust, silt and other debris in the water that could otherwise clog the system over time.
Their second job is protecting your ro membrane. Membranes in modern systems are made of a material that would be damaged by chlorine. And an activated carbon pre-filter will make sure this does not happen.
Their third, and maybe most important task is trapping organic contaminants. This kind of contaminants is not filtered out by the membrane.
The ro membrane is the center of your filtration system. There are two different types used in point-of-use reverse osmosis units, cellulose triacetate (CTA) membranes and thin film composite membrane (TFM or TFC).
Since the price difference nowadays is negligible, better choose a system with a TFC membrane. Although they need an activated carbon pre-filter to protect them from chlorine, their rejection rate for contaminates is much better than their CTA counterparts. Plus they last longer.
CTA membranes on the other hand should only be used with chlorinated water to prevent the growth of bacteria and mold.
RO Holding Tank
Under sink and whole house reverse osmosis systems include a tank to store the purified water that passed the membrane. Portable reverse osmosis systems usually do not have a tank.
RO filters with a tank are more convenient. They clean water before you need it – so it is readily available once you open the connected faucet. That is a huge advantage over tank-less RO water filters.
Choose the tank size wisely. A 4 gallon tank does not hold 4 gallons of water. Inside is a bladder, which limits the volume a bit. Additionally, the tank is under pressure. As a consequence, with low incoming water pressure, it does not fill up completely.
Generally a bigger tank is better, although more expensive.
Build-in under sink reverse osmosis systems come with their own faucet. Some even have an electronic filter change indicator.
Air gap faucet
All RO systems clean their membrane regularly by flushing it. This water should go down the drain, and never enter the system again. Even if the sink drain is clogged.
Air-gap faucets have a physical barrier to avoid drain water flowing back into the system. Alternatives are on-way valves you find in systems without air-gap faucets.
Post Filter or Polishing Filter
Your purified water may sit a while in the tank. When you run water from your kitchen faucet, the water leaves the holding tank and seeps through this filter. It makes sure the water tastes good and is clean. This usually is another activated carbon filter.
You probably saw 4-stage reverse osmosis systems and RO devices with up to 11 stages. An 11-stage reverse osmosis filter usually includes extra pre- and post filters as well as an UV-light to ensure optimum water purification.
What optional RO system components are available?
UV light is a proven technology to disinfect water. It destroys the DNA / RNA of bacteria and viruses, so they can no longer reproduce.
If your tap water is chlorinated, an extra UV light is not necessary. If your water comes from a well or any other source that could be polluted with microorganisms, I would consider it.
It is important to know, that an UV light needs electricity and regular bulb replacements.
Alkaline or re-mineralization filter
Reverse osmosis water contains no minerals. So it tastes kind of flat. Some people like it, others don't.
An alkaline or re-mineralization filter is an extra stage, where minerals are added to the water. That also raises the pH level slightly.
A pump to increase water pressure (booster pump)
You system will rely on water pressure to work. If the water pressure at your place is too low or too irregular, an additional booster pump will increase the water flow and production rate of clean water.
Most booster pumps need electricity. Home Master offers a different solution with their permeate pump. No electricity necessary for this one.
The ideal water pressure is around 60 PSI. If you have less than 40 PSI, you should plan to add a booster pump.
Installation & Maintenance
The installation of a new reverse osmosis system is no rocket science. Some manufacturers make it easier with fast-click connections, color coded pipes and clear instructions.
The only part I consider a bit tricky is the extra hole in your counter-top you would need for the RO faucet. No problem for an experienced DIYer, but a challenge for everyone else. Some people get creative and just hang the extra faucet somewhere near the sink. Not pretty, but it works without damaging the sink or counter top.
In case you plan to install a booster pump and don't have an outlet near the sink, you would probably need an electrician. Alternatively you could just string an extension cord there. Messy, but a solution if you don't own the place.
Like all other types of water filters, RO systems need a bit of maintenance. But they require a lot less work than gravity filter systems you have to refill manually or faucet filters with their 3-monthly filter changes.
Once a year, you should sanitize the system, check for leakage and control the tank pressure. Ideally you time it with a filter change.
How often do you change a reverse osmosis water filter?
The filter change interval depends on your system. While some systems only need new filters once a year, others require an earlier filter change.
It is important, that you follow the manufacturers' recommendations, as the ability to protect you from contaminants declines over time.
Some models like the Watts Premier are equipped with monitors that indicate when a filter change is due. If your system lacks this feature, you can install a water meter or monitor before the filter or simply follow the time recommendations by the manufacturer.
What happens if I forget to change the filters?
First, don't panic.
In many cases, the amount of clean water produced by your filter will simply go down before your water starts to contain dangerous levels of contaminants.
Strange taste or smell could also indicate that a filter change is due.
If you forgot to change the filters in your RO filter system in time, just do it as soon as possible. Nowadays you can order replacement filters for most systems i.e. from amazon and have them delivered to your doorstep.
Do I need to clean my reverse osmosis system?
Yes, cleaning and sanitizing your system is part of the regular maintenance plan. You can either hire a professional or do it yourself. As all filters should be replaced after sanitizing the whole system, timing is right can save you some money.
Factors that can limit the performance of your RO filter system
The performance of a reverse osmosis membrane can vary. It depends on a combination of factors as especially pH level or temperature of the incoming water as well as water pressure.
RO membranes are designed to work with cold water. And it should be obvious, that you also must protect your system from freezing.
The ability of the membrane to reject salts and other contaminants decreases with rising water temperature. On the other hand, if the water temperature in winter is lower, water filtering will take a bit longer.
You need a certain amount of water pressure for your RO system to work, increasing the pressure will result in a higher flow rate.
That is why it is important to pay attention to the water pressure you have at home and compare it with the ideal pressure your system is designed for. Not all membranes have the same water pressure tolerance.
In case your water pressure is too low, an electric pump can solve that issue. The opposite case, too high water pressure, is unlikely if you are connected to a public water system. And all well owners should be able to control the pressure in their system.
If you get your water from a public supplier, you are on the safe side. They have to adjust the pH level before they deliver it to you. Well owners might need to measure it regularly and adjust it according to their RO systems needs.
High TDS levels
RO systems are made to reduce the TDS level by nearly 100%. But, if the incoming water has a high TDS level, your systems needs to work harder and might need longer to fill the clean water tank.
All RO units I discuss here come with a pre-filter. If your water is loaded with sediment or other particle matter, you need to change this filter quite often.
High contaminant levels
Same is true for a high concentration of contaminants. The higher this level the more often the membrane needs flushing. As a result, your system takes a bit more time to produce clean water.
Which contaminants can reverse osmosis remove?
|Average Reduction %
|Arsenic (in chlorinated water)
A typical reverse osmosis filter also reduces Aluminum, Ammonium, Bicarbonate, Calcium, Chlorine, Chloromines, Chromate, Cyanide, Ferro cyanide, Iron, Magnesium, Mercury, Manganese, Phosphate, Silicate, Silver, Sodium, Strontium, Sulfate, Sulfite, Thiosulfate, Zinc up to 98%.
Does reverse osmosis filtration remove fluoride?
The discussion is heated – is fluoride in water a blessing or a curse? And I don‘ t want to get into it here.
But that much is clear:
If you want to remove fluoride from water, a reverse osmosis system can help you.
Reverse osmosis does remove fluoride from water, but in most cases does not eliminate it completely. Additional filtration is needed to reduce the level of fluoride in water further.
Especially designed RO systems for fluoride removal are available on the market.
What can pass through a reverse osmosis membrane?
The reverse osmosis membrane is only one part of your whole reverse osmosis system. If you would just use the membrane, organic contaminants like formaldehyde, methanol, acetonitrile, methyl ethyl ketone and others, would still be up in your water.
But no reverse osmosis filtration system comes without activated carbon filters. These filters protect you from organic compounds in your drinking water. Their varying size and quality are one reason for the differences in removal rates of various RO water filters.
How long does a reverse osmosis system last (lifespan)?
With a bit of care, your RO system can purify water at your home for up to 10 - 15 years. Just follow filter and membrane change intervals and clean it once a year. During this time you may also need to replace some parts like the faucet or storage tank, though.
Although the initial cost for a reverse osmosis system is relatively high, they also tend to last much longer.
Pro’s and Con’s of RO systems
What are the advantages of a RO water filtration system?
RO filters a wide range of contaminants
RO water systems can remove the widest range of contaminants from the water. Especially for radioactive particles, they are a good solution.
Clean Water on demand
Your systems refills the tank automatically.
Fewer Filter Changes
Most systems can run a year without a filter change. And they filter a lot more gallons than pitcher or faucet water filters.
Are there any disadvantages of reverse osmosis water systems?
Yes, there are a few.
RO removes minerals from the water
Along with contaminants, beneficial minerals like magnesium or calcium don't pass the RO membrane. Additional filters to re-mineralize the water after cleaning are an option, if you believe your food does not provide you with enough minerals.
RO systems are not suitable for emergency situations
The need to have a certain water pressure makes reverse osmosis unfit as a filter during all kind of disasters where the water supply is interrupted. Preppers prefer gravity water filters, as they neither need electricity nor water pressure to work.
RO wastes water
Although the waste water ratio of modern RO systems has improved, it stays a fact, that a certain amount of water is discarded.
RO membranes can't remove chlorine or VOCs (volatile organic chemicals)
A reverse osmosis water filtration system is only complete with additional, activated charcoal filters. And these filters will remove chlorine as well as VOCs.
What to look for in a Reverse Osmosis Filter System – A buyer’s guide
Let me state the obvious: there is no best reverse osmosis water filter system that fits everyone.
First, there are differences in size. Generally bigger systems equal higher prices.
Then there are add-ons to basic reverse osmosis filter systems, you may or may not need like an UV-lights or alkaline filters that increase the price as well.
And finally, your water quality. Just as an example, high sediment levels or water fluoridation in your area may call for extra filtration stages. Same is true for some other contaminants that are not removed by reverse osmosis alone.
Efficiency: How much clean water does it produce?
The volume of water a system can filter is measured in gallons per day (GDP).
Manufacturers state gpd rates that are usually a bit higher than what you can get at home. They measure under ideal conditions, while yours may vary.
Additionally, they often only tell your the GDP of the membrane, not the whole system which is usually a lot lower.
The amount of water that is that would be readily available at once depends a lot on tanks size and how fast it refills.
In general, the more filtered water a system can produce, the higher also the price.
What tank size do you need?
The size you should go for depends mainly on the number of people (and pets) you want to serve. Tank size, or the absence of a tank, determines how much filtered water will be at hand immediately.
It takes some time to refill the tank, so the ideal tank size is the amount of water you would need at any given time.
If you plan to connect it to your refrigerator or ice maker, plan for a bit more.
Re-mineralize or not?
Personally, I believe that most of us get enough minerals with our food. And the range of minerals an extra filter would add is not that balanced. They usually use calcite which increases the ph of the water and adds some taste.
I can see a benefit for whole house reverse osmosis systems, as a higher pH would also protect pipes and fittings from leaching lead and other metals. But for under sink ro filters, with the alkaline filter being the last stage before the faucet. Not much to protect if the faucet is lead-free as it should be.
The only reason to spend money on this would be taste. If you prefer the mineral water taste, and that makes you drink more water, then go for it. Because drinking more water is healthier.
Effectiveness: Do you need extra filtration stages?
If you read my explanation of pre-filters above, you understand, why pre-filters are an important part of any reverse osmosis system.
While one pre-filter would be enough, better systems come with two pre-filters that share the job. Ideally the second one has a smaller micron size than the first one.
Should I buy a counter top, under sink or whole house RO system?
Countertop reverse osmosis filter systems are generally more compact, mounted to your faucet and often lack a pressurized tank for water storage.
On the other hand, they are a lot easier to install and do not require any drilling or changes to your pipes. That makes them ideal for apartments or RV homes. If you look for a counter top model, have a look at my review of the top countertop reverse osmosis water filters.
Under sink reverse osmosis water filters come in various sizes and are cheaper than the counter-top versions. Hidden out of sight, they also do not clutter your counter top.
Additionally, many have larger filters which last longer. And the holding tank makes sure, there is always water on demand.
Whole house reverse osmosis filter systems make sense if you need to clean all water used in your house.
Recommended filter change intervals
The recommended filter change interval can be as short as every 6 month or up to one year or longer. Longer filter change intervals are not only more convenient. Replacement filters are also a regular cost factor.
Is an air gap RO faucet included?
Sometimes you simply do not have a choice. Plumbing codes in many areas still require the use of an air gap RO faucet.
Many systems are combined with an air-gap faucet. Some brands even offer various designs to pick from.
Air-gap RO faucet or not?
The main disadvantage of air gap faucets over other solutions is the gurgling sound the make while the tank fills. That can be quite annoying if you have an open kitchen. The also need slightly bigger holes in the counter top or sink to mount.
Some manufacturers seems to trust their own product a bit more than others. While some are bold enough to give you a lifetime warranty, others do not have one at all. The average warranty length for RO systems is one year. If it is longer, I consider that a plus.
[¹]Calculated using list prices (02/2018) with cheapest filter packs and shortest recommended filter change intervals. I did not use special offer prices! Back to budget filter, back to high capacity systems