Reverse osmosis (RO) systems remove contaminants such as dirt, chemicals, PFAS, microorganisms, and heavy metals from your drinking water. Most budget-friendly reverse osmosis systems cost between $199 and $300, though higher-end systems can cost over $1,000. Installation costs vary depending on the system and the home, according to Shu Saito, a plumber and water filtration expert with All Filters LLC.
“Owners can expect to pay anything from $300–$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 ultraviolet (UV) purification,” Saito said.
Our team reviewed the best reverse osmosis systems to help you choose the right one for your home and family. Continue reading to learn more about our top pick, the Waterdrop G3P800 8-Stage Tankless RO System, as well as other models we recommend for different situations and budgets.
Key Takeaways
- Our top pick is the Waterdrop G3P800 8-Stage Tankless RO System, which features an 800-gallon daily capacity, third-party testing, and a 10-stage filtration system that removes PFAS, heavy metals, chlorine, radioactive substances, and more.
- Reverse osmosis systems vary significantly in cost, with more affordable systems costing around $199–$300 and high-end systems costing between $500 and $1,000.
- When shopping for a reverse osmosis system, prioritize the number of filtration stages and system capacity to ensure you have sufficient water for your household’s needs.
- A reverse osmosis system with 3–5 filtration stages is suitable for most homeowners, but if you live somewhere with heavy water contamination, opt for systems with 6–10 stages.
Top 5 Reverse Osmosis Systems
- Waterdrop G3P800 Tankless RO System: Best Overall
- AquaTru Classic Countertop Water Filtration Purification System: Best Countertop System
- APEC Water Systems ROES-50 5-Stage RO System: Best Budget System
- iSpring RO500-BN Reverse Osmosis System: Best Daily Performance
- Express Water RO5DX 5-Stage Under Sink RO System: Best Under-Sink System
Compare Top Reverse Osmosis Systems
The table below highlights our top picks for the best reverse osmosis systems, covering key factors such as filter stages and warranty information.
| Product | Image | Filter Stages | Form Factor | Warranty |
|---|---|---|---|---|
Waterdrop G3P800 Tankless RO SystemCheck Price |  | 10 | Under-sink | 1 year |
AquaTru Classic Countertop Water Filtration Purification SystemCheck Price | | 4 | Countertop | 3- and 4-year protection plans available |
APEC Water Systems ROES-50 5-Stage RO SystemCheck Price | | 5 | Under-sink | 2 years |
iSpring RO500-BN Reverse Osmosis SystemCheck Price |  | 3 | Under-sink | 1 year |
Express Water RO5DX 5-Stage Under Sink RO SystemCheck Price |  | 5 | Under-sink | 1 year |
Our Reviews of the Best Reverse Osmosis Systems
Read the following reviews for a quick overview of each reverse osmosis system, including costs and pros and cons.
Best Overall
Waterdrop G3P800 Tankless RO System
Good for: A 10-stage filtration system that removes more contaminants than most products on the market
This model features a 10-stage filtration system that effectively removes PFAS, heavy metals, radioactive contaminants, fluoride, and other contaminants from your water. This home water filtration system takes up very little space under the sink, while providing improved water quality with its long-lasting filters. Our team appreciates its high flow rate of 800 gallons per day, ensuring you don’t have to worry about slow, inefficient water filtration.
Pros and Cons of Waterdrop G3P800 Tankless RO System
- Filters one cup of water in just five seconds
- Removes PFAS, heavy metals, radioactive substances, lead, and more with a 10-stage filtration system
- Features an integrated UV light, which kills microorganisms and has a lifespan of up to 50 years
- More expensive than many other systems we reviewed
- Some customers report that it’s a noisy model
Key Features
- Filter Stages: 10
- Form Factor: Under-sink
- Warranty: 1 year
What People Are Saying About The Waterdrop G3P800 Tankless RO System
Some Amazon customers noticed massive changes in water quality while using this system, with some saying they bought water testing kits and saw significant improvements. Other reviewers mentioned impressive customer service experiences in which the representative thoroughly explained and diagnosed problems. Many customers said this system was easy to install, often only taking 2–3 hours, including the time to remove an old system. On the downside, some customers said the system is sometimes noisy, particularly when it “auto flushes.”
Best Countertop System
AquaTru Classic Countertop Water Filtration Purification System
Good for: A countertop system that takes minutes to set up and doesn’t require plumbing installation
This efficient countertop filtration system uses affordable filters that last for six months to two years, along with third-party certified, patented technology that removes hazardous tap water contaminants. Our team appreciates that this countertop model requires no installation and features a removable tank, four-stage filtration system, and user-friendly dispenser button.
Pros and Cons of AquaTru Classic Countertop Water Filtration Purification System
- Filters 83 contaminants and PFAS out of your water
- Doesn’t require plumbing installation
- Homeowners can place the removable tank in the fridge for cold water
- Has only four stages of filtration, fewer than the other products in this review
- Protection plan is only available if purchased separately
Key Features
- Filter Stages: 4
- Form Factor: Countertop
- Warranty: 3- and 4-year protection plans available
What People Are Saying About The AquaTru Classic Countertop Water Filtration Purification System
Customers satisfied with their AquaTru Classic Countertop Water Filtration Purification System mention its high-quality filters, which provide good-tasting and clean water. Reviewers also mentioned the company’s accommodating customer service and how representatives address issues promptly. Customers also appreciate that the system is tall enough to fit a kettle underneath. Unhappy reviewers expressed concerns about the product’s durability, with some reporting leaks on their kitchen counters.
Best Budget System
APEC Water Systems ROES-50 5-Stage RO System
Good for: An all-in-one purchase that comes with a lead-free designer faucet, tubing, and other parts
This budget-friendly system costs hundreds of dollars less than most reverse osmosis systems and includes everything needed for installation. For homeowners on a budget, this system provides five stages of filtration, double carbon blocks, and a post-carbon filter to improve overall water taste and quality without breaking the bank. Plus, its leak-free connect fittings reduce the risk of leaks.
Pros and Cons of APEC Water Systems ROES-50 5-Stage RO System
- Reduces 99.99% of impurities in drinking water, such as chlorine, lead, and PFAS
- Unique double carbon blocks maximize contact with water, improving filtration quality
- Gives back through a company donation program that helps with clean water access globally
- Has a lower water capacity of up to 50 gallons per day
- Requires power tools to install
Key Features
- Filter Stages: 5
- Form Factor: Under-sink
- Warranty: 2 years
What People Are Saying About The APEC Water Systems ROES-50 5-Stage RO System
Customers have praised the APEC system for its straightforward installation, affordable prices, and sturdy faucet. Many Amazon reviews reported that their water quality significantly improved after installing this system, and it isn’t as noisy as other models they’ve previously used. However, some customers said they dislike the plastic design and mention issues with leaks.
Best Daily Performance
iSpring RO500-BN Reverse Osmosis System
Good for: A system with a fast flow rate and up to 500 gallons of filtered water daily
This next-generation system features a fast flow that can keep up with the demands of large families, offices, and restaurants. Our team likes that this model has a solid 2:1 pure water to wastewater ratio, saving up to 400% in water compared to traditional reverse osmosis systems, which helps keep your water bills down. Additionally, this system requires a quick installation and features a sleek, tankless design, leaving ample space for storage under the sink.
Pros and Cons of iSpring RO500-BN Reverse Osmosis System
- Has an easy-to-install design, according to customer reviews
- Fills an 8-ounce cup in just 10 seconds
- Features a simple twist replacement for filters
- Only has three stages of filtration, fewer than many other options on the market
- One of the more expensive models in this guide
Key Features
- Filter Stages: 3
- Form Factor: Under sink
- Warranty: 1 year
What People Are Saying About The iSpring RO500-BN Reverse Osmosis System
Many customers mentioned how fast this reverse osmosis system works, the ease of changing the filters, and its compact design, as it takes up hardly any space under the sink. Some customers reported that this model works well with well water and leaves no lingering odd flavors. On the other hand, those unhappy with the system said it failed more quickly than expected, with some reporting the LED lights stopped working within weeks of purchase and the system leaked within a few months.
Best Under-Sink System
Express Water RO5DX 5-Stage Under Sink RO System
Good for: A lightweight under-sink system that’s easy to install and won’t weigh down fragile plumbing systems
This five-stage reverse osmosis system filters pesticides, microorganisms, chlorine, arsenic, lead, and PFAS. It features a leak detection system that immediately shuts off the water flow if moisture is detected, preventing costly water damage. If you’re looking for an easy-to-install reverse osmosis system, this unit is praised for its user-friendly installation and even comes with extra pre- and post-filter sets, so you’ll have clean drinking water for up to a year.
Pros and Cons of Express Water RO5DX 5-Stage Under Sink RO System
- Comes with an all-in-one kit that requires minimal tools to install
- Has an emergency leak stop detector that shuts off the water flow if a leak starts
- Uses eco-friendly coconut carbon filters for a clear, natural taste
- Customer reviews mention issues with leaking and subsequent water damage
- Has a smaller water tank than other models in this guide
Key Features
- Filter Stages: 5
- Form Factor: Under-sink
- Warranty: 1 year
What People Are Saying About The Express Water RO5DX 5-Stage Under Sink RO System
Customers on Amazon mentioned how easily they can replace the quick-change filters due to this system’s unique swivel connection. Many people feel the system is durable and leaves their water tasting great, with no odor whatsoever. However, dissatisfied customers talked about issues with the storage tank breaking down and poor customer support that failed to fully address their concerns.
Reverse Osmosis System Buying Guide
To help you buy a reverse osmosis system for your home, we’ve broken down the most important factors to consider so you can make an informed purchase. Learn more about system capacity, water pressure levels, and safety features below.
Reverse Osmosis System Size
Reverse osmosis systems vary significantly in size. Most models in this review are designed to store underneath a sink, although you can also find countertop versions. Measure the space under or around your sink to determine if you have sufficient room for a tankless reverse osmosis system or if a larger model would better suit your kitchen.
Additionally, consider how many gallons of water per day (GPD) you need for your home.
“I recommend a 50–75 GPD flow rate for an under-sink or countertop reverse osmosis system if you’re in a smaller household of 1–2 people—this should cover your drinking and cooking needs,” said Justin Cornforth, CEO of Ace Home Co. “For a household with three or more people, go with a 100–150 GPD flow rate so you have ample water available throughout the day.”
Reverse Osmosis System Filters
Reverse osmosis systems have multiple stages of filtration, moving water through 3–8 filters to remove contaminants. Learn more about common types of filters below.
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 of filter removes chlorine.
A reverse osmosis membrane removes particles larger than water molecules, such as sand, silt, and clay.
This type of filter kills microorganisms.
These filters remove specific types of contaminants present in large quantities, such as nitrate or fluoride.
Reverse osmosis systems can house anywhere from three to over 10 filtration stages, but how do you determine which level of filtration is right for your home? Saito recommends getting your water tested first to reveal contaminants that might need removal.
“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.
Under-Sink vs. Countertop Systems
As the name suggests, under-sink reverse osmosis systems are typically installed underneath your kitchen or bathroom sink, whereas countertop systems sit out in the open. The right type for you will largely depend on your home setup.
“Go with an under-sink reverse osmosis 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,” Cornforth said.
Cornforth added that under-sink reverse osmosis systems are the most popular option, allowing for faster water flow.
“Opt for a countertop reverse osmosis system only if you’re renting, have very limited under-sink space that’s hardly possible to modify, or need portability,” he added. “Countertop models are cheaper, but they clutter counters and are better suited for temporary use.”
Cornforth said under-sink models declutter a space and cost around $200, or $300 with a water tank, but are also simple enough for a do-it-yourself (DIY) project.
“Under-sink systems are easy to install and most homeowners can handle it themselves,” he said. “But if you don’t want to deal with installing the system yourself, plan on spending around $150 for professional installation.”
How Do You Install a Reverse Osmosis System?
The majority of reverse osmosis systems are point-of-use systems that attach to one outlet of water—typically the one under your kitchen sink, although you can buy countertop models.
Here’s a list of general steps for installing most reverse osmosis systems:
- Gather the proper tools and read the instructions that came with your reverse osmosis system.
- Make room underneath your sink so you can easily access the drainpipe and cold water shut-off valve. Also make sure there’s space for the tubing.
- Turn off the cold water supply.
- Consult the manufacturer’s instructions and determine whether you need to drill a hole in the sink or the countertop for the faucet stem. The guide should also include information on the ideal size of the hole. Some countertops come with a covered hole predrilled in them, which we recommend checking for before drilling.
- Insert the faucet stem into the hole and follow the manufacturer’s instructions to secure the faucet to your sink or countertop using the included mounting hardware.
- Install the drain saddle, which connects the wastewater and drainpipe, by drilling a hole in your drainpipe above the p-trap. Place the drain saddle around the drainpipe and mark the drilling location with a Sharpie marker before drilling.
- Using a wrench, remove the riser that feeds the cold water side of your faucet, then connect the swivel end of the angle stop valve to the cold water shut-off valve’s threads. Once in place, reconnect the riser tube.
- Most reverse osmosis systems have color-coded tubing. Using your manufacturer’s instructions, install the matching tube to each line, including one to the tank, faucet, and drainpipe.
- Use the mounting brackets or provided hardware to connect the reverse osmosis system underneath the sink. Most systems are mounted near the front of the cabinet, with the tank in the back.
- Start up your system and follow the provided instructions to flush the system properly. Double-check that nothing is leaking before continuing use.
FAQs About Reverse Osmosis Systems
What are the downsides of reverse osmosis?
The downsides of reverse osmosis include wasted water, larger energy bills (especially with big systems), and the removal of beneficial minerals. Reverse osmosis systems thoroughly remove a large amount of contaminants and PFAS, but they can also remove essential minerals, such as calcium and magnesium, which contribute to good health.
Is a reverse osmosis system really worth it?
Yes, a reverse osmosis system is worthwhile in most cases, as it can remove up to 99.99% of contaminants in drinking water, including chlorine, lead, bacteria, PFAS, and fluoride. Most systems are easy to install for a DIY-ready homeowner and are cost-effective when compared to the price of bottled water, making them a budget-friendly investment.
What are alternatives to reverse osmosis systems?
Common alternatives to reverse osmosis systems include mechanical filters and activated carbon filters. Mechanical filters remove suspended particles from the water, such as silt, sand, clay, and organic matter. They don’t remove heavy metals or other contaminants that reverse osmosis systems usually can.
On the other hand, activated carbon filters absorb impurities, including unwanted tastes and odors, residual chlorine, and organic compounds, but won’t remove microorganisms, chemicals, and metals.
Our Methodology
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 on Amazon. We looked at positive and negative reviews alike, focusing on information from both satisfied and critical buyers.
- Expert insights: Through years of experience, we’ve learned that listening to what others have to say is key to building accurate, well-rounded articles. 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 products with the latest versions and eliminating any discontinued models. From there, we pared the list down by comparing each model’s feature set and selecting the best-in-class options for a variety of buyers, budgets, and scenarios.
Why You Can Trust Us
This Old House has empowered homeowners and DIY enthusiasts 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 for the home, from doorbell cameras and dining room decor to circular saws and snow blowers.
Once we conclude the research and testing phases, we craft a comprehensive, user-friendly article of recommended products and additional information to help our readers make the right purchase.
