Investing in and installing a reverse osmosis water filter gives you cleaner, more pure water by removing dirt, chemicals, microorganisms, heavy metals, and other contaminants and impurities. These systems can vary greatly in price, with budget-friendly models starting around $150–$300 and higher-end systems running anywhere from $500–$1,000. Installation costs can also vary depending on the system and the home, according Shu Saito, a plumber and water filtration expert with All Filters LLC.
“Owners can expect to pay anything from $300 to $1,200 for the unit and installation, but these costs will be partly dependent on the complexity of the plumbing and any add-ons desired, such as storage tanks or UV purification,” he said.
Our team has reviewed some of the best reverse osmosis systems for your home to help you choose the right one for your home. Overall, our top pick is the Waterdrop G3P800 8-Stage Tankless RO System, which uses a nine-stage filtration system to eliminate over 100 harmful contaminants from your water. Read our guide below for more of our top picks.
Our Top Reverse Osmosis System Picks
A reverse osmosis water filtration system is an easy form of water treatment. It works by removing contaminants from your tap water during the filtration process.
However, before deciding on which RO system works best for your home, there are several factors you should take time to consider to ensure you’re making the right purchase, such as the capacity of the system, the water pressure levels, and the amount of safety features.
The list below highlights our top picks for the best reverse osmosis systems.
- Waterdrop G3P800 8-Stage Tankless RO System: Best Overall
- AquaTru 4-Stage Countertop RO System: Best Countertop System
- APEC Water Systems ROES-50 5-Stage RO System: Best Budget Pick
- iSpring 6-Stage Reverse Osmosis System: Best Value
- Express Water RO5DX 5-Stage Under Sink RO System: Best Under Sink System
- Whirlpool WHAROS5 RO Water Filtration System: Best Design
- Ecoviva Countertop Reverse Osmosis System: Most Compact
Compare Top Reverse Osmosis Systems
The table below compares features of the best reverse osmosis systems based on our methodology.
| Product | Retail Link | Filtration Stages | Installation | Warranty |
|---|---|---|---|---|
|
Waterdrop G3P800 9-Stage Tankless |
9 |
Under-sink |
1 year |
|
|
AquaTru 4-Stage System |
4 |
Countertop |
1 year |
|
|
APEC ROES-50 5-Stage |
5 |
Under-sink |
2 years |
|
|
iSpring RCC7AK 6-Stage |
6 |
Under-sink |
1 year |
|
|
Express Water RO5DX 5-Stage |
5 |
Under-sink |
1 year |
|
|
Whirlpool WHAROS5 5-Stage |
5 |
Under-sink |
Lifetime |
|
|
Ecoviva 4-Stage System |
4 |
Countertop |
2 years |
Best Overall
Waterdrop G3P800 8-Stage Tankless RO System
We like this tankless reverse osmosis model for those looking to save space under your sink. It features a nine-stage filtration system that removes 114 harmful contaminants like heavy metals, PFAS, and nitrates. The kit includes a smart faucet that displays the current TDS level and filter life.
Pros and Cons of Waterdrop G3P800 8-Stage Tankless RO System
- Has an integrated UV light to kill microorganisms with a lifespan of up to 50 years
- Can pour a cup of water in about 6 seconds
- Offers a massive water flow rate of up to 800 gallons per day
- Is priced significantly higher than many other systems
- Some customers found the system to be noisy
Customer Reviews of the Waterdrop G3P800 8-Stage Tankless RO System
Customers praised this system’s effectiveness. Several customers purchased tap water testing kits to determine the efficiency of this system and found that the water it provided was comparable to filtered bottled water. However, we also saw that some customers found its faucet to be flimsy, and some said it was overly loud while in operation.
“The reverse osmosis system is a high-quality product. The installation process is extremely easy and quick, as any person can install the system due to the clear instructions manual. The filtered water tastes crisp, refreshing, and pure. It tastes no different from bottled water. I would recommend it to anyone who wants refreshing clean water. The customer service was very quick to respond and was extremely patient with my questions and responses.” — Guo L. Huang via Amazon
“Tankless system requires an internal pump, which has to run every time you open the faucet. And also in the middle of the night when it does its flushing process. Spec is 65 dB, but to make it simple, we can hear the downstairs system flushing in the middle of the night from our upstairs bedroom with the door closed. Our kitchen is open to our family room, where we watch TV – every time someone gets water, we have to pause the TV. Some are claiming the noise isn’t that bad – I don’t understand how unless the unit is in a pretty thick cabinet or somehow farther away from where the humans are.” — Jim via Amazon
Best Countertop System
AquaTru 4-Stage Countertop RO System
Purify water on your countertop and cut down on installation time with this small reverse osmosis system. We liked that it includes a removable tank, a four-stage filter, and a dispenser button.
Pros and Cons of AquaTru 4-Stage Countertop RO System
- Doesn’t require plumbing installation
- Uses specialty filters that may last up to two years before a replacement filter is needed
- Purifies 1 gallon of tap water in as little as 12 minutes
- Provides four stages of filtration, which is fewer levels than the other options in this review
- Is priced higher than many direct-connection systems
Customer Reviews of the AquaTru 4-Stage Countertop RO System
Customers we found said that this reverse osmosis system was strong enough to remove even solid particles from the gallons of water it filtered. However, customers who weren’t satisfied with their purchase complained that it stopped working after a short period of time, while others were disappointed in how often this filter needed to be refilled.
“I have purchased other big-name brand water filters. I was very disappointed in the taste of their filtered water-it tasted of minerals and just plain yucky, for lack of a better word. I’ve heard good things about the AquaTru filter and thought I’d give it a try. I just received it and put it together yesterday. The water is so pure and delicious! It was very easy to assemble and prime to get it going! It is well made and it looks beautiful on my kitchen counter. I love the convenience of having it right where I need water! I highly recommend this AquaTru water filter! You’ll love it.” — Janet Tope via Amazon
“I drink a lot of water during the day and the amount of filtered water in the pitcher only lasted one day before having to be refilled again. The design seemed inefficient in that a lot of ‘waste’ water had to be emptied each time, and everything cleaned daily with soap and water. Too much of a hassle.” — Susan P. via Amazon
Best Budget Pick
APEC Water Systems ROES-50 5-Stage RO System
This versatile reverse osmosis system removes over 99% of contaminants including chlorine, arsenic, lead, and more. We like that this system uses five-stage filtration to purify mineral-rich well water or standard tap water. Plus, it comes with leak-free connect fittings that don’t require any extra lock clips to seal leaks.
Pros and Cons of APEC Water Systems ROES-50 5-Stage RO System
- Comes with everything you to need to install it, including a drain saddle and food-grade tubing
- Can purify mineral-rich well water
- The fittings have stainless steel teeth for gripping
- Not NSF certified
- Requires power tools for installation
Customer Reviews of the APEC Water Systems ROES-50 5-Stage RO System
Reviews we found complimented the efficiency of this system, which multiple customers said saved them more energy and money than previous reverse osmosis systems they had used. However, some customers weren’t satisfied with the system’s installation process, which required a cordless drill to drill holes. Others found that it didn’t reduce their water level’s TDS by as much as they were hoping.
“I am submitting this review 3 months after installation. I couldn’t be happier with this system! I have a lot of iron in my well water, use a softener to remove most of the iron and harness. However, the water still has a slightly funny taste and is yellow from suspended iron. This system finished the job. Not only does my water taste good, it’s perfectly clear now. I am so pleased, that I took the time to run a line from this system to my ice maker in my refrigerator.” —Michigan Shopper via Amazon
“For whatever reason, this system did not work very well for me. I was mostly trying to reduce total dissolved solids in our well water for use with an ice maker. Our TDS value is about 67 from our well water. With the system installed, TDS was reduced, but only down to about ~42, so maybe a ~35% reduction. Not great, not terrible. We never had any taste/odor issues with our water, so I can’t comment on the efficacy of the carbon filters— the RO seems marginal at best though.” — Clay N. Cowgill via Amazon
Best Value
iSpring 6-Stage Reverse Osmosis System
We were impressed that this system removes up to 99% of asbestos, fluoride, and other harmful chemicals. After removing contaminants, this six-stage reverse osmosis system remineralizes your water. This dual-function system makes water healthier and tastier.
Pros and Cons of iSpring 6-Stage Reverse Osmosis System
- Comes with a 100% satisfaction guarantee from the manufacturer
- Includes instructional videos and customer support to make the installation process easier
- Has a fine reverse osmosis membrane
- Some customers have mentioned leaking
- Has been issued a Proposition 65 warning from the California government, indicating that it may expose users to chemicals
Customer Reviews of the iSpring 6-Stage Reverse Osmosis System
Our team found that customers frequently complimented how easy to install this system was, with the process being easy enough for even those with no DIY experience to manage. Reviewers who rated this product poorly complained that the system’s parts leaked.
“Love this system! Super easy to install with video and easy instructions. Had extremely high nitrates (+20). After installation, nitrates were down to 7! Water tastes amazing. The only issue I had was with my new RO system faucet leaking. I contacted customer service via email and received a response…. Wow! I cant say enough about the service I received!” — Stacy via Amazon
“I really want to like this product. Actually, I have bought it three times since the price is reasonable. However, 3 out of the 3 installations had something leaking. The first two times were an o-ring on one of the large filters. I used Vaseline as recommended, but for some reason, the o-ring area leaked. They fortunately provide spare o-rings (probably knowing this is a common issue) so I replaced the o-ring, re-installed and everything was just fine. So either their o-rings have some kind of quality issue, or their design does, but it looks like the design is a very commonly used design.” — Turbo97se via Amazon
Best Under Sink System
Express Water RO5DX 5-Stage Under Sink RO System
This five-stage reverse osmosis system includes filters that remove pesticides, chlorine, and microorganisms. It also has a leak detector that stops water flow if moisture is found. We saw that the filters are also double-sealed to further protect against leaks.
Pros and Cons of Express Water RO5DX 5-Stage Under Sink RO System
- Has a high temperature rating of 100 degrees Fahrenheit
- Has a lightweight body that’s ideal for fragile plumbing systems
- Can be customized with add-ons, such as deionization filters
- Has a slower water recovery than competing systems
- Some customers said that the water storage tank broke down
Customer Reviews of the Express Water RO5DX 5-Stage Under Sink RO System
Our team noticed that customers praised this RO’s filter design because the swivel connections allowed for quick-change filters without removing any tubing. However, dissatisfied customers complained about the system’s maintenance process, which required regular intensive cleaning in addition to filter changes. Others felt the flavor of the water after it passed through this RO system still did not taste right.
“We live in Hawaii and usually had to fill up water jugs to get filtered water. No more! It’s an investment, but man, it is worth it! It does take a minute to install and figure out, so definitely dedicate some time to putting it together. We’ve had it for several months and no complaints. The water tastes great, and the tap works amazing. It looks sleek and clean as well. 10/10 recommend.” — Amazon Customer via Amazon
“The countertop osmosis filter didn’t meet my flavor expectations. Despite using it consistently for two weeks, it retains an unpleasant plastic aftertaste that doesn’t resemble refreshing, clean water. Additionally, the need to frequently refill the container due to the waste water occupying most of it is inconvenient. This results in having to fill both sides regularly, consuming a significant amount of water. Furthermore, the instructions for setting up the product are unclear.” — Julian Kwan via Amazon
Best Design
Whirlpool WHAROS5 RO Water Filtration System
Our team found that this water filtration system is a great low-cost option that still features a large capacity and easy installation. It removes up to 15 contaminants, including lead and chlorine and has a modern faucet design that won’t look out of place in your kitchen.
Pros and Cons of Whirlpool WHAROS5 RO Water Filtration System
- Has an EZ-change indicator light that tells you when the filter needs to be changed
- Includes easily removable filters
- Can remove up to 15 contaminants
- Has a bulky design
- Wastewater rates are not indicated
Customer Reviews for the Whirlpool WHAROS5 RO Water Filtration System
We found that customers who were impressed with this product particularly liked that it was easy to install, made for great-tasting clean water, and that it produced quick results. On the other hand, we also saw some customers who felt that some of the parts were not high quality, and others felt as though it wasted too much water.
“I have well water at home, it’s very hard (>30gpg) and has fairly high TDS (500ppm), I run through a sediment filter (5micron) then a water softener, then for drinking water it goes though this RO filter. Immediately after installation the TDS went from 500 down to 60 (ppm). After running it for a few days the TDS dropped even further to about 26ppm — this was my expectation and I’m pleased with it’s performance. I will keep this system for as long as it keeps producing water of this quality.” — C. Farmer via Amazon
“RO system like this one is known to produce clean and waste water which is discharged to the drain. Filter-based filtration systems, on the other hand, don’t waste water. So I expected waste water, but I didn’t know it wastes so much water until I measured it. Since none of the documents specify the amount of wasted water, I decided to measure it and was surprised. To be fair, the quality and taste of the produced, clean water is great.” — hermits via Amazon
Most Compact
Ecoviva Countertop Reverse Osmosis System
Good for: Homeowners seeking a countertop model with a sleek design that will blend in with other kitchen appliances.
This compact, attractive countertop reverse osmosis system is easy to set up. Since it’s portable, you can move it around your home when needed or bring it with you when traveling. Despite its small size, it has a durable design with a thick, reinforced glass carafe, and it delivers four-stage filtration that removes over 1,000 contaminants.
Pros and Cons of Ecoviva Countertop Reverse Osmosis System
- Delivers fast water dispensing
- Sleek LCD screen with straightforward button-control operation
- Delivers a three-to-one pure-to-drain ratio, helping you use less water overall
- Delivers only four-stage filtration
- Can only fill 1,200 mL (40 oz.) at a time
Customer Reviews of the Ecoviva Countertop Reverse Osmosis System
Our team found that customers who gave this product a positive review liked that it had a compact design and that it worked quickly to filter water. Additionally, others were impressed that it was easy to use and significantly improved water taste. However, others found it laborious to have to empty the tank after each use, and others said it didn’t always fully fill the carafe.
“This counter top water purifier is excellent. The water tastes so much better than my unfiltered tap water. I was surprised to see that my water quality is actually pretty good, but this device still made a significant difference in the taste, and there is no more chlorine smell or presence. It actually removes impurities in the water rather than just improving taste, like some gravity-fed pitcher filters.” — fire_lion via Amazon
“The product did not fill the carafe even if the tank was full. Tried it several times and it won’t work. I waited for two days and worked again, but on and off. The other frustrating issue is that it doesn’t have an off/on button, so you have to unplug it all the time to start. It doesn’t start if you leave it plugged. For me, it is not safe to be plugging and unplugging it.” — ML via Amazon
Reverse Osmosis System Buying Guide
Before purchasing a reverse osmosis system, consider the following attributes to select the best system for your home.
Determine the Right Size for an RO System
Reverse osmosis systems can vary greatly in size. Most models we examined are designed to be stored underneath a sink, although countertop versions also exist. Measure how much space you have under or around your sink before deciding whether you need a tankless reverse osmosis system or if you have room for something larger.
You should also consider how many gallons per day (GPD) is appropriate for your home.
“I recommend a 50–75 GPD flow rate for an under-sink or countertop RO system if you’re in a smaller household of 1-2 people—this should cover your drinking and cooking needs,” according to Cornforth. “For a household with 3 or more people, go with a 100–150 GPD flow rate so you have ample water available throughout the day.”
Types of Reverse Osmosis System Filters
The type of RO system mount not only impacts cost but also the functionality of the system. Justin Cornforth, Ace Home Co. CEO, explains the pros and cons of both options.
Reverse osmosis systems have multiple stages of filtration, moving water through three to eight filters to remove contaminants. Common types of filters we found include:
This filter introduces calcium and magnesium into the purified water to balance its pH level.
This type of filter removes dirt and other large particles.
This type removes chlorine.
An RO membrane removes particles that are larger than water molecules.
This type of filter kills microorganisms.
These filters remove specific types of contaminants, such as nitrate or fluoride. They’re only needed if these contaminants are present in large quantities.
Under-Sink vs. Countertop RO Systems
“Go with an under-sink RO system if you want a cleaner look, quicker water access, and a long-term solution—it’s worth the setup effort to keep your counters clear,” he said.
Cornforth added that under-sink RO systems are the most popular option, but also allow for faster water flow.
“Opt for a countertop RO system only if you’re renting, have very limited under-sink space that’s hardly possible to modify, or need portability,” Cornforth advises. “Countertop models are cheaper, but they clutter counters and are better suited for temporary use.”
Other than decluttering a space, Cornforth said most under-sink models cost around $200, or $300 with a water tank, but are also simple enough for a DIY project.
“Under-sink systems are easy to install and most homeowners can handle it themselves,” he says. “But if you don’t want to deal with installing the system yourself, plan on spending around $150 for professional installation.”
Number of Filters
RO systems can house anywhere from three to over 10 filtration stages, but how are you supposed to know which level of filtration is right for your home? Saito recommends getting your water tested first.
“A water test could reveal some contaminants that might need removal, thus guiding you in selecting a system that best suits your needs,” he said.
According to Cornforth, a 3–5 stage RO system is ideal since it includes sediment and carbon filters in addition to the RO membrane, which should be enough to clean municipal water. More filters are needed if you use well water, or have high levels of chlorine, lead, or heavy metals.
“Go with 3–5 stages for standard municipal water, 6–8 stages for well water or heavy contamination, and 7–9 stages if you want to drink clean water but without removing beneficial minerals and making it too flat to the taste,” Cornforth said.
The Bottom Line: Our Top Picks
Our top pick is the Waterdrop G3P800 8-Stage Tankless RO System*, but it’s a little bulky and expensive. If you’re looking for a smaller, countertop option, we love the AquaTru 4-Stage Countertop RO System.* If you’re on a budget, go for the APEC Water Systems ROES-50 5-Stage RO System.*
*Links above to product retail page.
Reverse Osmosis Systems FAQs
How does a reverse osmosis system work?
A reverse osmosis system removes dirt, bacteria, and chemicals from your drinking water. It does this by passing water through a series of filters that each target a specific contaminant. Since the filters are semipermeable membranes, they allow water to pass through them while trapping undesirable molecules. The resulting water is purer than standard tap water.
Why do I need a reverse osmosis system?
A reverse osmosis system can provide your whole house with healthier and better-tasting water. However, our team notes that it’s especially important to use a reverse osmosis system if you live in an area with poor water quality.
How often do I need to replace the filters in my reverse osmosis system?
In our experience, you should replace the filters or filter cartridges in your reverse osmosis system at least once per year or by following manufacturer guidelines. If a filter gets clogged or damaged, replace it sooner. Some reverse osmosis systems have warning systems that tell you when a filter is failing or nearing the end of its life.
Saito says that each type of filter has its replacement cadence, but it is generally best to replace filters in stages instead of all at once. These can range from sixth monther intervals to once every two years.
Do reverse osmosis systems have water tanks?
Some RO filtration systems have a tank that stores water before it’s transferred to your sink. Others forgo the tank to save space. The type you purchase should depend on how much space you have in your kitchen.
What is an NSF Certification?
The National Sanitation Foundation (NSF) is an independent, third-party certification organization that tests and certifies products and services to ensure they meet certain public health and safety standards.
When a water filter is NSF certified, it means that it has been tested and found to meet or exceed specific performance standards for the reduction of a variety of contaminants, such as lead, chlorine, bacteria, and other impurities. This can provide peace of mind to consumers, knowing that the filter they are using has been independently verified to be effective at removing potentially harmful substances from their drinking water.
Furthermore, many government agencies and organizations require NSF certification for water filters to ensure that they meet specific standards for public health and safety. For example, many states require NSF certification for water filters used in schools, hospitals, and other public facilities.
Can I install a reverse osmosis system myself?
While you can always hire a professional to install a reverse osmosis filter in your home, passionate DIYers can also try it on their own if they have the right materials, including an adjustable wrench, pencil or marker, screwdriver, and drill.
Our Methodology
This Old House has empowered homeowners and DIY-ers for more than four decades with top-notch home improvement advice in the form of television programs, print media, and digital content. Our team focuses on creating in-depth product and service review content. To date, we’ve published over 1,600 reviews on products in the home space, including power tools, outdoor equipment, major appliances, kitchen gadgets, electronics, and more that focus on product quality and helpfulness to our readers.
To provide our readers with the best recommendations possible, we rely on several key sources of information to help guide our selection process.
Initial Research: Our research process began by generating a list of reverse osmosis systems with a significant number of verified buyer reviews and an average customer review rating of 4–5 stars. We looked at positive and negative reviews alike, focusing on information from both satisfied and critical buyers.
Expert Insights: To complement our in-house expertise, our team looked at reviews and videos from trusted publications and independent testers, spoke with subject matter experts, and drew insights from reader contributions.
Final Product Selection: We then began fine-tuning our list by replacing older models with the latest versions and eliminating any discontinued models. From there, we compared each model’s feature set to create a final short list, selecting the best-in-class options for various buyers, budgets, and scenarios.
Once we conclude our research, we craft a comprehensive, user-friendly article of recommended products and additional information to help our readers make the right purchase.
