Independent, unbiased reviews of the best undersink reverse osmosis water filters on the market. Check out the top 5 under sink reverse osmosis water filters of 2024 below.
THE BEST UNDER SINK REVERSE OSMOSIS WATER FILTERS 2024
1: Waterdrop G3-W RO Filtration System
2: US Water Systems Alkaline Reverse Osmosis System
3: APEC ROES-50 RO Water Filter System
4: iSpring RCC7AK RO Water Filter System
5: Express Water ROALK5D RO Alkaline Water Filter
INDEPENDENT REVIEWS
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Check out the best undersink reverse osmosis water filters below and discover how you can transform the quality and purity of your home water supply today.
1: WATERDROP G3 W REVERSE OSMOSIS WATER FILTER
FEATURES
• 7-STAGE FILTRATION
• NSF & CE CERTIFIED
• WATER SOFTENER
• COMPACT DESIGN
• NO STORAGE TANK
SEVEN STAGE FILTRATION
The Waterdrop G3-W is the best undersink reverse osmosis water filter on the market. It uses a seven-stage water filtration system to deliver excellent results.
It is built with a 0.0001 high-performance reverse osmosis filter membrane and employs three composite water filters. This means all contaminants larger than 0.0001 microns are removed from the water.
NSF & CE CERTIFIED
The Waterdrop G3-W undersink RO filter is both NSF and CE certified. NSF certification means the filter has been tested and meets the strict standards set by the National Sanitation Foundation.
It is also CE certified which means it has passed the health, safety, and environmental protection standards of the European Union. You can rest assured that the Waterdrop G3-W performs as per the manufacturer’s claims.
SOFTENS WATER
The high-performance filtration system also removes calcium and magnesium particles from your tap water. This means your water is also softened.
High levels of calcium and magnesium minerals in water cause water hardness. Water hardness damages home appliances and limits the effectiveness of soap and detergents. The Waterdrop G3-W eliminates this problem.
COMPACT TANK FREE DESIGN
The Waterdrop G3-W RO filter is a tank free design. It delivers freshly filtered water to the faucet without storing it in a tank.
This means it is a smaller, compact unit that fits neatly under your sink. The device measures just 4.3” x 17.5” inches. It also removes complications associated with water storage such as potential leaks and microbial growth.
WATER FLOW RATE
The system has a filtered water flow rate of 1500 liters per day. This will easily meet the requirements of a family home. And, will satisfy the needs of most small companies.
It has a good filtered water to wastewater ratio of 1:1. This cuts down on wastewater and reduces the volume of water being consumed for every glass of filtered water produced.
SUMMARY
The Waterdrop G3-W reverse osmosis water filter is a solid performer and a strong contender on the best undersink reverse osmosis water filter list for 2024. It has a range of unique selling points including its compact size and tank-free design.
This makes it an attractive option if you have limited undersink space. Measuring just 4.3” x 17.5” inches the Waterdrop RO filtration system will comfortably fit beneath most kitchen sinks.
2: US WATER SYSTEMS ALKALINE REVERSE OSMOSIS SYSTEM
FEATURES
• EXCELLENT PERFORMANCE
• 99% CONTAMINANT REMOVAL *
• REDUCED WASTEWATER
• MINERAL REPLACEMENT
• AMERICAN MADE
* removes up to 99% of total contaminants
FILTRATION PERFORMANCE
The 200-AARO-LIV undersink reverse osmosis water filter achieves excellent results in terms of contaminant removal. The device removes up to 99% of water contaminants from your tap water including chlorine, lead, fluoride, mercury, and microbes.
It also produces significantly less wastewater compared to other models on the market – 80% less wastewater. And, the post-filtration polishing filter does a great job of enhancing water clarity and improving taste.
FILTER OPTIONS: 5 vs. 6
The filtration system comes with an option of a five or six-filter set-up. The optional sixth filter is a ‘Livation’ hydration chamber. It adds minerals, lowers the ORP, and increases the pH of the water.
The six filters used in the 200-AARO-LIV model are (1) sediment filter, 5-micron, (2) primary carbon block filter, (3) secondary carbon block filter, 1-micron, (4) RO membrane, (5) Livation hydration chamber, and (6) carbon polishing filter to improve the taste.
ALKALINE WATER
The US Water Systems RO water filtration system not only filters your water, it also neutralizes acidity and creates alkaline water. The optional Livation hydration chamber adds minerals and increases the pH of your tap water – neutralizing acidity.
This means your tap water is transformed into Alkaline water. Water with a pH above 7 is alkaline water. And most tap water supplies lie in the acidic end of the scale.
AMERICAN MADE
The US Water Systems RO filtration system is 100% American-made. It is advertised as the only undersink RO water filter that is 100% made in America.
This RO filter is built using FDA and NSF-compliant materials and is completely BPA-free. It also uses a double o-ring seal to ensure there is no leakage – so that all water passing through the system is being filtered 100% of the time.
HIGH PRESSURE PUMP
The unit also comes with a high-pressure permeate pump. This is a great option for ensuring water pressure remains high across the system from start to finish.
The pump is non-electric and cuts out pressure loss as the water passes through the reverse osmosis membrane. It’s a great option for guaranteeing faucet water pressure and for connecting to ice makers.
SUMMARY
The 200-AARO-LIV reverse osmosis filtration system from US Water Systems is an excellent choice for any home. It boasts excellent build quality, impressive filtration performance, and is 100% American-made.
It even comes with a 5-year warranty which shows confidence in performance and longevity. The alkaline water capability is a welcome bonus and the pressure pump is a good option if you need a boost to maintain water pressure in your home.
3: APEC ROES-50 REVERSE OSMOSIS WATER FILTER SYSTEM
FEATURES
• 5-STAGE FILTRATION
• 99% CONTAMINANT REMOVAL *
• DEDICATED FAUCET
• GUIDED INSTALLATION
• AMERICAN MADE
* removes up to 99% of total contaminants
FIVE FILTRATION STAGES
This APEC undersink RO water filtration system employs five filter stages for excellent results. It removes up to 99% of water contaminants including lead, fluoride, heavy metals, arsenic, chlorine, and a wide range of microbes.
The five filters used are (1) sediments filter, (2) firest carbon filter, (3) second carbon filter, (4) high rejection RO membrane, and (5) a post-filtration refining filter. You are guaranteed to be left with great tasting, crystal clear, filtered water.
AMERICAN MADE
This is an American made device. The APEC reverse osmosis filtration system is designed, engineered, and assembled in California, USA.
It has been manufactured to industry standards and is certified by the Water Quality Associated, (WQA). APEC has over 20 years of experience in the water filtration industry.
DEDICATED FAUCET
The filtration unit comes with a dedicated faucet for your kitchen sink. This means you can keep your regular tap water supply separate if you prefer.
The faucet has been ergonomically designed for ease of use. It has a 360-degree rotation capability, a brushed nickel finish, and a smooth disc valve shut-off.
FOUR GALLON STORAGE TANK
The APEC ROES-50 comes with a pre-pressurized 4-gallon water storage tank. This means you will always have filtered water available when you need it – no more waiting around.
The storage tank holds filtered water until it is required. And, when the level on the tank begins to drop – the RO filter kicks in and replenishes the supply to top it back up again.
DIY INSTALLATION
If you feel comfortable trying your hand at some home plumbing, then DIY installation may be an option for you. However, if you are a novice our advice is to get a professional in to install the unit.
The APEC ROES-50 comes with an online step-by-step installation value to guide through the installation requirements. The steps involved are also detailed in the user manual that is supplied with the device.
SUMMARY
The APEC ROES-50 water filter has a lot going for it. We particularly like the five-stage filtration system, the 99% contaminant removal, and the high-quality American design and engineering.
It has a user friendly dedicated faucet and a large storage tank that means you’ll never run out of filtered drinking water. The APEC ROES-50 is a serious contender.
4: iSPRING RCC7AK RO WATER FILTER SYSTEM
FEATURES
• 6-STAGE FILTRATION
• REMINERALIZATION STAGE
• ALKALINE BALANCING
• COMPACT SIZE
• SIMPLE INSTALLATION
WHAT COMES IN THE BOX?
First up, what can you expect when you unbox the the iSpring RCC7AK reverse osmosis filter? Alongside the RCC7AK reverse osmosis filter you will find a brushed nickel faucet, a storage tank, and a tool kit for installation and maintenance.
The inclusion of a faucet means you will have a dedicated faucet in your sink for filtered water coming from the iSpring filter. And, you can continue to use your existing tap for all other tasks that don’t require high-quality filtered water.
6-STAGE FILTRATION
The iSpring RCC7AK is a high-performance 6-stage reverse osmosis water filter. The first five stages perform the water filtration steps and a sixth stage is used to remineralize the water and adjust the pH to optimum levels.
The iSpring performs superbly when it comes to water filtration. It has been rated to remove up to 99% of water contaminants. This includes chlorine, fluoride, asbestos, arsenic, calcium, sodium, and lead.
REMINERALIZATION STAGE
Like all high-performance reverse osmosis filters, the iSpring RCC7AK removes some of the good along with the bad. This means that while unwanted water contaminants are being removed from your water source – so too are many of the minerals that occur naturally in water and are beneficial to our health.
To compensate for this the sixth stage is used to address this problem. This stage restores the mineral content to your water to balance anything that was lost during the filtration process. It also improves the taste of the water as pure water can taste unfamiliar to your taste buds.
ALKALINE PH BALANCING
This 6th stage not only remineralizes the water but also adjusts the pH to optimum levels. It is also used to restore the alkalinity level of your filtered RO water.
The high-performance 5-stage reverse osmosis water filtration process tends to generate slightly acidic water. When this happens the pH of your water can dip below 7. To neutralize this acidity, the 6th stage performs a balancing step that boosts the of your RO filtered water.
EASY INSTALLATION & MAINTENANCE
The iSpring RCC7AK is easy to install, maintain, and operate. The device comes with all the parts you will need to do a DIY installation yourself if you feel comfortable tackling the job at hand. However, if you want to stay on the safe side we recommend you call in a professional plumber.
The RO filter comes with detailed, step-by-step instructions that walk you through the installation process. And, if you need some real-time help you can contact iSpring customer support for technical assistance.
CERTIFICATION
The device is certified to NSF/ANSI 58. NSF/ANSI 58 certification is the American National Standard for point-of-use reverse osmosis water filtration systems.
It uses an ultra-fine reverse osmosis water filter to remove contaminants down to a size as small as 0. 0001 microns. That’s very small! A GAC fine filter then polishes the purified water and finally, an AK filter restores mineral content and optimal alkaline balance.
SUMMARY
The iSpring RCC7AK is a highly impressive undersink reverse osmosis water filter. It employs a 6-stage water filtration process that boasts remineralization and an alkaline adjustment step.
This means it replaces beneficial minerals that are removed by the RO filtration membrane and restores alkalinity to optimize the pH.
The device is easy to install and is compact in size – measuring 15.5” x 5.1” x 19.5” inches (L x W x H). It has a capacity of 75 gallons and uses a dedicated faucet so you can continue to use your existing tap for tasks that don’t require highly purified RO water.
5: EXPRESS WATER ROALK5D REVERSE OSMOSIS ALKALINE WATER FILTER
FEATURES
• 10-STAGE SYSTEM
• DEDICATED FAUCET
• ALKALINE FILTER
• ACTIVE MINERAL TECHNOLOGY
• 4-GALLON TANK
FIVE FILTRATION STAGES
The Express Water ROALK5D Reverse Osmosis Alkaline Water Filter combines five filtration and five remineralization stages. The five filtration stages are a sediment filter to remove dirt, dust, and sand, a granular activated carbon filter, an activated carbon block, a high-performance reverse osmosis membrane filter, and finally a post mineralization activated carbon filter.
FIVE MINERALIZATION STAGES
The ROALK5D uses a five-stage mineralization system to add ionically activated minerals to your water once it has been filtered. The minerals added include calcium, magnesium, and potassium.
The five-stage mineralization system is placed after filters 1-4. This means remineralization occurs directly after the reverse osmosis filtration step but before the final activated carbon filtration stage.
DIMENSIONS
The Express Water ROALK5D weighs 29.5 pounds and measures 19 x 18 x 19 inches. It’s a pretty big unit and is bulkier than some of its leading competitors on this list. You’ll need a little extra space in your kitchen for this one.
If you are planning on having it installed beneath your kitchen sink – get the measuring tape out and make sure you have enough room before you order the device. It’s better to be safe than sorry.
CHROME FAUCET & TANK
The device comes with a dedicated chrome faucet. This means you can keep your existing tap for unfiltered water. The faucet has a 360-degree rotation capability which means it can be turned in any direction and facilitates easy pouring of water.
The storage tank holds four gallons of freshly filtered water. This means you will have round-the-clock access to RO filtered water anytime you need it – no waiting around.
INSTALLATION
Installation is again pretty straightforward – as is the case with all the best undersink reverse osmosis water filters. There is a set of easy-to-follow installation instructions.
Although we were happy with the process – we recommend getting a professional in if you have any concerns. A plumber will ensure all your water piping and connections are correctly fitted and there are no leakages.
SUMMARY
The Express Water ROALK5D undersink reverse osmosis water filter is a solid performer. It employs a five-stage filtration system and a five-stage mineralization setup to produce high-quality reverse osmosis filtered water.
The ROALK5D is a little bigger than some of its competitors and measures 19 x 18 x 19 inches. It is NSF certified, comes with a 1-year warranty, and is simple to install. If you want an RO water filter with a large storage tank – this could just be the one for you.
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WHAT IS AN UNDER SINK REVERSE OSMOSIS WATER FILTER?
An undersink reverse osmosis water filter is a high-performance water filtration system that sits beneath your kitchen sink. It is plumbed into your water supply and provides filtered water directly to your kitchen faucet.
It uses a water filtration process called Reverse Osmosis, sometimes referred to as ‘RO’. This is a highly effective method of water filtration that removes up to 99% of all impurities.
RO FILTRATION STAGES
A reverse osmosis water filter employs several filtration stages. The most powerful step involves the use of an RO membrane. This membrane is semi-permeable and allows water molecules to pass through while blocking contaminants.
They achieve superior results compared to standard water filters – such as activated carbon water filters. This means you and your family can enjoy a much higher quality of freshly filtered water with an RO system.
There is also the option of a countertop reverse osmosis water filter. This device sits on your kitchen counter and you manually top it up each time you need filtered water.
HOW DO UNDERSINK RO FILTERS WORK?
Let’s take a look at how undersink reverse osmosis water filters work. Specifically, we will look at how they are installed and how they operate.
CONNECT DIRECTLY TO WATER SUPPLY
Under sink reverse osmosis filters are installed at the point of use in your home. This means the filtration system is connected to your water supply directly below your kitchen sink.
Your regular tap water supply is piped into the RO filter and the purified water is fed to a faucet in your kitchen sink. The filter itself is out of sight and needs no interaction until the filters themselves need to be replaced.
Most undersink reverse osmosis filters use a four-phase filtration system. They employ a sediment removal phase, activated carbon phase, reverse osmosis phase, and a water storage phase.
SEDIMENT REMOVAL PHASE
The first phase in an RO filtration system is a pre-filtration step called sediment removal. This involves removing crude pieces of material.
This phase removes large particulates that would otherwise damage and limit the performance of the activated carbon filters and the reverse osmosis membrane.
ACTIVATED CARBON PHASE
The next step is the activated carbon step. This passes your tap water through an activated carbon filter. Some systems employ two activated carbon filters for greater results.
These filters pass the water through a special type of media that binds contaminants and traps them inside the filter. Meanwhile, water molecules pass freely through the filter and emerge on the other side.
REVERSE OSMOSIS MEMBRANE PHASE
This is the real heart of the operation. The reverse osmosis membrane is a high-performance, highly effective water filter.
It is a semi-permeable membrane. This means it has tiny microscopic holes that allow water to pass through but block even the smallest of contaminant particles.
WATER STORAGE PHASE
Once the water has been purified it is fed into a water tank for storage. The RO filter will continue to feed this tank until it is full.
When you run your faucet it will draw RO filtered water from this tank. When the drops, the RO filter kicks back in and begins refilling the tank with filtered water.
BENEFITS OF AN UNDER SINK REVERSE OSMOSIS FILTRATION SYSTEM
Undersink reverse osmosis filters are an excellent option for domestic water filtration. They achieve much better results compared to a standard water filtration system, are easy to install, require no electricity, and will save you a ton of money in the long term.
AUTOMATIC WATER SUPPLY
Undersink reverse osmosis filtration systems are installed at the point of use. They are fitted directly to your kitchen sink water supply.
This means you never have to think about topping them up with water. This happens automatically. All you have to do is turn on your faucet – and you have freshly filtered RO water.
If you compare this to a countertop water filtration device – it has to be manually topped up each time you require water. Undersink filters remove this step and are supplied with water automatically.
EXCELLENT WATER QUALITY
A reverse osmosis water filter is a high-performance water filter. It purifies water to a much higher standard than regular water filters such as activated carbon filters.
Reverse osmosis water filters remove up to 99% of all contaminants from your water source. When you install an undersink RO system you are guaranteed the highest water quality in your home. All the devices on our best undersink reverse osmosis water filter compilation deliver excellent water quality.
SAVES COUNTER SPACE
Installing the filtration system beneath your sink means you free up counter space. The reverse osmosis system will be fitted beneath your kitchen sink, so it will be out of sight and out of mind.
This frees up your countertop space leaving you space to work with or store other devices. If you want to optimize counter space – an under sink device is an excellent choice.
DEDICATED FAUCET
The best undersink reverse osmosis water filters come with a specially fitted, dedicated faucet. When the unit is installed below the sink it comes with a separate water line and faucet.
This means you have a dedicated faucet for high-quality RO filtered water. And, you get to keep your regular tap for regular tap water. It gives you the option of choosing regular water or freshly filtered RO water.
SAVE MONEY
You will save money when you invest in an RO water filtration system. Although the initial investment will set you back, you immediately begin saving money by producing fresh filtered water at home.
You no longer have to buy bottled drinking water at the store, you can just run your RO faucet at home. Over the lifetime of the filtration system, you will save a significant amount of money.
SIMPLE INSTALLATION
The installation of an RO filtration system requires a little work, but it’s not complicated. The best undersink reverse osmosis water filters come with simple instructions and online installation videos to help you on your way.
If you have any concerns at all, we recommend you hire a professional tradesman to install the unit for you. This way you can be sure it has been done correctly. For more see – The Pros & Cons of an Undersink Reverse Osmosis Water Filter.
RELATED
SHOULD I BUY AN UNDERSINK REVERSE OSMOSIS WATER FILTER?
Yes, buying an under sink reverse osmosis water filter is an excellent idea. They provide a continuous flow of high-quality, freshly filtered water to your kitchen sink.
Reverse osmosis filters are high-performance water filters. The best reverse osmosis undersink water filters remove up to 99% of all contaminants and provide a continuous flow of freshly filtered water directly to your kitchen.
They are an excellent investment and you’ll recoup your initial costs by removing the need to purchase expensive bottled drinking water. Instead, you’ll be filtering your own at home. And, all with the press of a button.
