You are probably here because you want safe, healthy drinking water for you and your family or want to learn about water filtration systems. A home water filtration system can improve overall water quality throughout your house by removing contaminants, bacteria, and biofilms from your entire plumbing system.
Unfortunately, no tap water is safe anymore, even if you have “high quality” city or well water. Plus, there are no guarantees that bottled water is any better than your tap. Reverse osmosis (RO) systems filter water through a semi-permeable membrane that blocks contaminants such as lead, chlorine, and fluoride, making them an effective solution for safer drinking water and providing great tasting water for drinking and cooking.
RO-System.org is your reliable source for the best reverse osmosis system reviews and detailed information about all water filtration systems. Our experts test and rank the options so you don’t have to!
Our rankings are based on hands-on testing, features, price, total cost of ownership, warranty, and customer reviews.
Our Top Picks
#1 Overall: Waterdrop X Series X12
The smartest faucet, an integrated TDS meter, a UV filter, remineralization, and both the highest daily output and most efficient waste water ratio make this system the top choice!
Overview | Full Review
Runner Up: Home Master TMHP HydroPerfection RO System
With nearly every filter including ultraviolet, this system is the ideal option to power your refrigerator ice maker and can be easily customized.
Overview | Full Review
Best Mid-Range: NU Aqua Tankless 600 RO System
This tankless RO system is super-efficient and comes with a smart faucet, remineralization filter, and 120 day home trial guarantee.
Overview | Full Review
Best Budget: NU Aqua 7 Stage RO System
This affordable reverse osmosis water filter has lots of features including UV and remineralization at a great price.
Overview | Full Review
Top Reverse Osmosis Systems
Our top rated RO water filtration systems are “point-of-use” under sink systems, specifically under sink filters, that are installed and used at a single location, which is usually under the kitchen sink. Under sink installation may require some DIY skills, such as drilling into countertops and connecting plumbing, and you should consider the available cabinet space before installation.
These reverse osmosis water purification systems include a dedicated faucet that is installed alongside your standard tap water faucet to produce filtered water just for drinking and cooking. With additional parts, you can also run a pure drinking water line to your refrigerator, if it is has a water dispenser and/or ice maker. Routine filter change is essential for maintaining water quality and system performance.
Compared to other filter methods like pitcher filters or faucet filters, under sink systems with reverse osmosis technology can remove other contaminants that these alternatives may miss. Conducting a water test can help determine which system is best for your needs by identifying specific contaminants in your water supply.
If you want to learn more about the newer tankless style options we recommend, check out our review of the top tankless reverse osmosis systems.
1. Waterdrop X Series X12 Reverse Osmosis System
The Waterdrop X Series represents a significant advancement in under-sink systems, offering a compact and efficient solution for water purification.
With its efficient filtration process and 11 stages, it ensures clean, mineral-infused drinking water while minimizing waste. Advanced, user-friendly features make it easy to use and maintain.
High-Volume Filtration:
The Waterdrop X12 RO system delivers up to 1200 gallons of purified water daily, with a waste-to-pure water ratio of 3:1, and a fast flow rate of 3.75 seconds for a cup of pure water, outperforming many other systems in speed and convenience. Its filtration performance is driven by high-quality RO filters, which are designed for superior contaminant reduction, ensuring the removal of a wide range of impurities and meeting rigorous certification standards.
Tankless reverse osmosis systems provide continuous flow and save space compared to traditional tank systems.
Health Benefits
The multi-stage filtration process ensures contaminant reduction including bacteria, while the remineralization stage adds beneficial minerals back into the water.
Ease of Use
The system is user-friendly, featuring a smart faucet with real-time TDS monitoring and simple filter replacement, making maintenance hassle-free.
Learn more in our review of the Waterdrop X Series X12 or click the button below to visit the manufacturer’s website.
2. Home Master TMHP HydroPerfection Reverse Osmosis System
If you don’t to want waste time comparing options and just want to be sure you are covered in every situation, then the Home Master TMHP HydroPerfection is the perfect filtration system for you. It comes complete with every major feature and every possible filter – 9 stages in all! The system uses a variety of filter types, including sediment, carbon, remineralization, and UV filters, which work together to target a broad range of contaminants for comprehensive water purification.
Permeate pump
The Home Master TMHP includes a permeate pump, which increases the output of the system to 75 gallons per day and reduces the amount of waste water needed to flush the RO membrane to just 1 gallon for every gallon of purified drinking water produced.
Remineralization stage
It has a remineralization filter that adds safe calcium and magnesium minerals back into the RO water and raises the pH to be more alkaline. This creates a fresher tasting water that compares to good bottled water.
UV filter
The system also has a UV (ultraviolet) light that will kill 99.8% of microorganisms that may contaminate your water. Municipal water sources are usually low in microorganisms but well water and other natural sources can have higher levels.
In addition, Home Master comes with a 5-year warranty! When considering the operating cost, keep in mind the expenses for filter replacements and routine maintenance, which are important for long-term value.
For more details on this system, check out our full Home Master TMHP HydroPerfection reverse osmosis review or click the button below.
3. NU Aqua Tankless Reverse Osmosis System
NU Aqua Systems has joined the tankless trend and added the NU Aqua 600GPD Tankless reverse osmosis water filtration system (WU-600GPD-TL) to its already impressive lineup.
What sets this system apart?
It is tankless
It has an integrated pump and is not slowed down by a water tank so it can process up to 600GPD faster than a conventional under sink system. Unlike some systems that suffer from slower flow rates, especially when filling larger containers, the NU Aqua delivers a consistently strong flow without sacrificing filtration quality.
It is super-efficient
There is a 2:1 ratio of pure water to waste compared to other RO systems that only get 1:1 and many that get 1:2 or 1:3… The design also helps reduce overall water consumption compared to traditional RO systems, making it more eco-friendly and cost-effective.
Smart and compact
The RO faucet has an LED ring that glows blue to let you know everything is working normally or red to let you know that one of your filters needs to be replaced. The system body also has lights to show filter status and overall system health.
This is also one of the most compact systems you can put under your sink and is easy to install.
Lab data supports the NU Aqua’s performance claims and contaminant removal efficiency, providing confidence in its filtration capabilities.
For more details on this system, check out our full NU Aqua Tankless 600GPD Reverse Osmosis Review or click the button below.
4. Waterdrop G3 P800 Reverse Osmosis System
The Waterdrop G3 P800 is an evolutionary upgrade to the very popular Waterdrop G3 (P400) and offers an array of features that are not available in any other tankless under-sink RO systems.
Fast output
This system can produce a whopping 800 gallons of filtered water per day (GPD), which is enough for a very busy household and even small businesses that requires large amounts of filtered water.
Efficient processing
In addition, it does this with an exceptional 3:1 waste water ratio, meaning it creates only 1 gallon of waste water for every 3 gallons of pure water.
Extra features
This system comes with an integrated UV filtration stage that effectively removes any microorganisms that may still be present in the water and a built-in TDS (total dissolved solids) meter in the smart faucet to report the quality of the filtered water.
The Waterdrop G3P800 is NSF certified for its contaminant removal performance, including its ability to remove chlorine and lead.
For more details on this system, check out our hands-on Waterdrop G3 P800 reverse osmosis review or click the button below.
5. Frizzlife PD600-TAM3 with Alkaline Remineralization
The Frizzlife PD-600-TAM3 makes it near the top of the list of reverse osmosis water filtration systems because of its excellent features and competitive price tag.
What makes it so good?
Remineralization
The Frizzlife system comes with an alkaline remineralization filter that adds essential minerals back to the filtered water and raises the pH to more than 7.5.
Filtration of health-related contaminants
This system is highly effective at removing health-related contaminants such as lead and disinfection byproducts, helping to ensure safer and cleaner drinking water for your household.
Smart features
Only one other system on our list has an integrated digital TDS meter built into the system like this Frizzlife. This very helpful feature continuously tests and reports on the quality of your water after it has been filtered.
Tankless design
With the fastest 600 GPD RO membrane and an internal booster pump, this system has high throughput and is very efficient.
Combine all of the features above with the smaller size and easy maintenance of the tankless design and you have a system that is sure to provide great water in a great package.
For more details on this system, check out our full review of the Frizzlife PD600 or click the button below.
6. Home Master TMAFC-ERP Artesian Reverse Osmosis System
The Home Master TMAFC-ERP water filtration system combines the perfect balance of useful benefits, popular features, and value in one package.
There are two big features that set the TMAFC-ERP apart from other mid-range options and makes it one of the top clean water systems…
Remineralization stages
Water passes through a remineralization filter TWICE (a unique feature of the Home Master). This adds safe minerals back into the RO water and raises the pH to be more alkaline. The result is a fresher tasting mineral water that many people prefer.
Permeate pump
In addition, it comes standard with a permeate pump, which is a non-electric device that increases the water pressure before it enters the reverse osmosis membrane. This reduces water waste up to 80 percent and increases water production up to 50 percent.
Nice design features
The included “Fast Flow RO kit” uses larger fittings and tubing to speed up the fill rate at the faucet so you get water as fast as possible. Home Master makes high quality filters that are modular in design and built for easy filter changes without any tools.
Also, Home Master has an excellent 5-year warranty, which is better than most of the other top companies in our list.
For even more details on this system, check out our full Home Master TMAFC-ERP Artesian reverse osmosis review.