Reverse osmosis (RO) systems provide some of the most thorough water filtration available for homeowners. While common water filters found in pitchers, faucet attachments, refrigerators, and basic under-sink systems often rely on activated carbon to improve taste and reduce chlorine, reverse osmosis systems use a semipermeable membrane to remove many dissolved contaminants from drinking water.
To help you find the best reverse osmosis system for your home, we reviewed the top models on Amazon and compared filtration performance, capacity, and key features.
Key Takeaways
- Reverse osmosis systems vary significantly in cost, with basic models starting around $150–$300 and premium tankless systems costing $500–$1,000 or more on Amazon.
- Most homes using municipal water can get by with 3–5 filtration stages, while those with well water or higher contaminant levels may benefit from systems with 6–8 or more stages.
- When shopping for a reverse osmosis system, prioritize filtration performance, system capacity, and installation type to find the best fit for your household.
Top 5 Reverse Osmosis Systems
Check out our list of top picks for reverse osmosis systems on Amazon below.
- 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 High-Capacity System
- Express Water RO5DX 5-Stage Under Sink RO System: Best Leak Protection
Compare Top Reverse Osmosis Systems
The table below highlights our top picks for the best reverse osmosis systems, covering key factors like filter stages and warranty information.
| Product | Filter Stages | Design | Warranty |
|---|---|---|---|
Waterdrop G3P800 Tankless RO SystemCheck Price | 10 | Under-sink (tankless) | 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 (tankless) | 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: Buyers concerned about PFAS and other contaminants
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 significant 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 taking only 2–3 hours, including time to remove the 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: Buyers who want reverse osmosis filtration without 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
- Requires manual refilling of the water reservoir
- 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 have mentioned its high-quality filters, which provide clean, good-tasting water. They also talk about the company’s accommodating customer service and how representatives address issues promptly. Plus, customers 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: Budget-conscious shoppers looking for a reliable under-sink system
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
- Installation is more involved than some competing systems
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 praised this system for its straightforward installation, affordable prices, and sturdy faucet. Many Amazon reviews reported that their water quality significantly improved after installation, and it isn’t as noisy as other models they’ve used. However, some customers said they dislike the plastic design and reported leaks.
Best High-Capacity System
iSpring RO500-BN Reverse Osmosis System
Good for: Large households with high daily water demands
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% on water compared to traditional reverse osmosis systems, which helps keep water bills down. Additionally, this system has 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 Leak Protection
Express Water RO5DX 5-Stage Under Sink RO System
Good for: Buyers who want a straightforward under-sink installation
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 have 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 reported issues with the storage tank breaking down and with poor customer support that failed to fully address their concerns.
Reverse Osmosis System Buying Guide
To help you choose the right reverse osmosis system for your home, we’ve broken down the most important factors to consider. Start by evaluating system size, filtration stages, and cost, then compare system designs and installation requirements.
Reverse Osmosis System Size
Reverse osmosis systems vary significantly in size. Most models are designed to fit underneath a kitchen sink, although you can also find countertop versions. Before purchasing a system, measure the available space under or around your sink to determine whether you have room for an under-sink system, storage tank, or a countertop model.
It’s also important to consider how much filtered water your household uses each day. Reverse osmosis systems are commonly rated by gallons per day (GPD), which indicates how much purified water they can produce.
According to Justin Cornforth, the CEO of Ace Home Co, households with one to two people can typically get by with a system rated for 50–75 GPD, while households with three or more people may benefit from a system rated for 100–150 GPD.
Reverse Osmosis System Cost
Reverse osmosis systems typically cost between $150 and $1,000 or more, depending on their filtration capacity, design, and features. Basic countertop and traditional under-sink systems are often available for less than $300, while premium tankless models with higher flow rates, ultraviolet (UV) purification, and smart features can cost $500–$1,000 or more.
Installation costs vary based on the complexity of the system and your home’s plumbing. Many reverse osmosis systems are designed for do-it-yourself (DIY) installation, but professional installation can add approximately $150–$500 to the total project cost. Before purchasing a system, consider not only the upfront cost but also the long-term expense of replacement filters and maintenance.
Reverse Osmosis System Filters
Reverse osmosis systems use multiple filtration stages to remove contaminants from drinking water. While every system includes a reverse osmosis membrane, many also incorporate additional filters to improve water quality, taste, and safety. Depending on the system, filtration can also help reduce contaminants like lead, arsenic, nitrates, and per- and polyfluoroalkyl substances (PFAS), a group of synthetic chemicals often referred to as “forever chemicals.”
We’ll explain the most common types of water filters below.
A remineralization filter adds minerals like calcium and magnesium back into purified water. It can improve taste and help balance pH levels.
Sediment filters remove larger particles like dirt, rust, sand, and debris. They also help protect downstream filters from premature wear.
Carbon filters reduce chlorine, odors, and compounds that affect taste. They help improve the overall quality and flavor of drinking water.
A semipermeable membrane removes dissolved solids and contaminants from water. It can reduce impurities like lead, arsenic, nitrates, PFAS, and other dissolved pollutants.
UV filtration uses light to kill bacteria, viruses, and other microorganisms. It provides an additional layer of protection against biological contaminants.
Specialty filters are designed to address specific water-quality concerns. Common examples include filters that reduce fluoride, nitrates, or heavy metals.
The number of filtration stages you need depends largely on your water source and water-quality concerns. According to Cornforth, standard municipal water typically requires only three to five filtration stages, while homes with well water or higher contaminant levels may benefit from six to eight stages. He adds that systems with seven or more stages can provide additional filtration while helping preserve minerals that contribute to taste.
Pro Tip
- According to This Old House, standard carbon filters primarily improve taste and odor, while reverse osmosis systems can also remove dissolved solids commonly found in well water. If your home relies on a well or you’re unsure about your water quality, a reverse osmosis system may provide more comprehensive filtration.
Tankless vs. Tank-Based Systems
Reverse osmosis systems are available in both tankless and tank-based designs. Tankless systems filter water on demand and typically take up less space under the sink, making them a good option for smaller kitchens. They also refill more quickly and often produce less wastewater than traditional systems.
By contrast, tank-based systems store filtered water in a dedicated reservoir, providing a ready supply whenever you need it. While they require more under-sink space, they cost less than tankless models and can continue dispensing water during periods of heavy use.
Under-Sink vs. Countertop Systems
Under-sink reverse osmosis systems are installed beneath a kitchen or bathroom sink, while countertop systems sit on a counter and connect directly to a faucet. The right option depends on your available space, installation preferences, and long-term needs.
Under-sink systems are the most common type of reverse osmosis system. They keep filtration components hidden, preserve counter space, and typically provide filtered water through a dedicated faucet. These systems are often the best choice for homeowners who want a permanent filtration solution and use filtered water daily.
Countertop systems require little to no permanent installation and are often a good fit for renters, apartments, or homes with limited under-sink space. Although they take up counter space, countertop models are often easier to set up, move, and maintain than under-sink models. They also offer a solid option if you want the benefits of reverse osmosis filtration without modifying existing plumbing.
How Do You Install a Reverse Osmosis System?
Most reverse osmosis systems are designed for under-sink installation, though countertop models are also available. Systems typically include color-coded tubing, mounting hardware, and detailed instructions to simplify installation. Most under-sink models connect to an existing cold-water line and require a dedicated faucet and drain connection.
Installation difficulty varies by system type. Traditional tank-based systems require space for both the filtration unit and storage tank, while tankless models typically have a smaller footprint but may require access to an electrical outlet. Some installations may also require drilling a hole in the sink or countertop for a dedicated drinking-water faucet.
If you’re comfortable with basic plumbing projects, installing a reverse osmosis system is often a manageable DIY task. However, you may find professional installation worthwhile if you’re modifying plumbing, drilling through stone countertops, or simply want the assurance that the system is installed correctly. Some manufacturers may require professional installation to maintain warranty coverage, so review the fine print before purchasing a system.
FAQs About Reverse Osmosis Water Filtration 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, like calcium and magnesium, which contribute to good health.
Is a reverse osmosis water filtration system really worth it?
For many homeowners, a reverse osmosis system is worth the investment because it removes a wide range of contaminants, including lead, chlorine, PFAS, and dissolved solids. It can also provide a long-term alternative to bottled water while improving the taste and quality of drinking water.
What are alternatives to reverse osmosis systems?
Common water filtering alternatives include activated carbon filters and mechanical filters. While these systems can improve taste, odor, and sediment removal, they generally don’t remove as many dissolved contaminants as a reverse osmosis system.
How long does a reverse osmosis water filtration system last?
Most reverse osmosis systems can last 10–15 years or longer with proper maintenance. However, filters and membranes require periodic replacement, with replacement schedules varying by manufacturer and water quality.
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.
