Reverse osmosis is a reliable way to ensure that you have cleaner, safer, great-tasting filtered water on demand. Unlike many common, basic filtration solutions like refrigerator or pitcher filters, reverse osmosis systems offer a comprehensive, multi-stage filtration process.
The part of this process that gives these systems their name is a key component of how it works: in reverse osmosis systems, a tightly woven membrane is used to trap and flush out contaminants as small as a single atom.
But there’s much more to learn about what these solutions can do and how they work. In this guide, we’ll cover questions such as:
- What is reverse osmosis?
- What water quality issues does reverse osmosis address?
- How does a reverse osmosis system work?
- How is reverse osmosis different from filtration?
- What is the best reverse osmosis system?
- What is the lifespan of a reverse osmosis system?
Read on to learn more about reverse osmosis water filtration and what it can do for your home.
What Is Reverse Osmosis?
As noted above, reverse osmosis (RO) is a comprehensive water filtration process that pushes water through a semipermeable membrane, addressing a broad range of potential contaminants in drinking water.* A reverse osmosis filtration system typically also involves additional pre- and post-filtration stages, using different methods such as sediment and activated carbon filtration.
A high-performing, multi-stage RO solution can target many drinking water contaminants, including:
- Lead
- Microplastics
- Arsenic
- Chlorine
- Mercury
- Chromium
- TDS (total dissolved solids)
- And many more
The most comprehensive systems can also address emerging contaminants like microplastics and PFAS in drinking water, as well as issues like viruses and bacteria (which may be a concern for well water or if your area is under a boil advisory).
If you’re looking for more control over your drinking water, you’ll likely want the advanced, multistep filtration that an RO system can provide.
Concerned about potential water quality issues?
Learn more about common water problems and solutions with our Water Solutions Finder.
How Do Reverse Osmosis Filtration Systems Work?
Reverse osmosis water filter systems vary depending on the brand and design, but in general, they perform four key steps to help improve your water quality:
Step 1: Pre-Filtration
An RO system connects to your tap water line. These systems use high-pressure pumps to propel water through various levels of filtration. At this stage, tap water is called “feed water.”
The feed water passes through a series of initial filters, such as sediment and carbon filters, before flowing into the reverse osmosis chamber. These early filters can address issues such as:
- Sand
- Rust
- Large particles
- Chlorine tastes and odors
Step 2: Reverse Osmosis
Here, the feed water is pushed through the reverse osmosis membrane at pressure to filter out contaminants. In Culligan RO systems, this process uses an advanced membrane to separate contaminants as small as a single atom from the water. These could include heavy metals like lead, mercury and chromium.
Step 3: Specialty Filtration
More comprehensive systems also add additional filtration stages that can address a broader range of contaminants. These options include specialty filters like the Culligan Total Defense cartridge, which is proven to reduce forever chemicals (PFAS) as well as other concerns like pesticides, pharmaceuticals and volatile organic compounds (VOCs). Additionally, Culligan systems equipped with the Advanced Post-Tank Filter are certified under NSF Protocol P231 to reduce viruses, bacteria and cysts.
After these specialty filtration stages, some reverse osmosis systems, like Culligan’s, also give you the option to customize the taste of your water by adding back select minerals. Some systems also provide a final polishing filter after reverse osmosis is complete to make your water as crisp and fresh-tasting as possible.
Step 4: Drainage and Storage
After filtration, the system stores the filtered water (unless you have a tankless RO system) and drains out any wastewater. Some RO systems will generate more wastewater than others, which is why it’s best to look for high-efficiency options. For example, Culligan’s Aquasential® Smart Reverse Osmosis Drinking Water Filtration System is the world’s most efficient — it’s 3 to 5 times more efficient than other leading reverse osmosis systems.**
How Are Reverse Osmosis Systems Different From a Water Filter?
Reverse osmosis systems are a type of water filter, but the difference comes in what they can do. Most standard filters — like pitchers, fridge filters or faucet attachments — use only an activated carbon filter and mainly address chlorine taste and odor.
Because reverse osmosis systems combine multiple stages of filtration, they target a much broader range of substances, including both aesthetic issues like taste and smell as well as bigger concerns that can impact your home and health.
Here’s how other water filters compare to reverse osmosis:
Countertop Filters
A countertop filter is a much simpler, less comprehensive solution to common water quality concerns. It’s often good at targeting unpleasant tastes and odors and may handle common water components like chlorine and fluoride.
Pitcher Filters
Pitcher filters are convenient, but offer limited filtration capabilities, primarily addressing aesthetic concerns like taste and odor and treating only small volumes of water at a time. This often means frequent refills, routine filter replacements and limited capacity for addressing broader water quality issues.
Faucet Filters
Faucet filters are a common purchase, but their main benefit is simplicity. They are easy to install and can provide basic filtration directly from your tap, typically just targeting aesthetic concerns.
Fridge Filters
Refrigerator water filters are another convenient option for addressing drinking water concerns, such as reducing chlorine taste and odor. However, they also are generally limited in what concerns they can address.
Whole-Home Water Filtration
Whole-home water filters treat all the water that flows into your home. They’re meant for individual water problems that impact not just drinking but also cleaning, bathing and washing. These systems typically use specific types of filtration media designed to address specific issues such as:
- Chlorine
- Sulfur
- Iron
- Sediment
- Arsenic
- Nitrate
- PFAS
Simply put, whole-home filters are specialists covering individual water quality issues, while RO filters are generalists, addressing a broad range of potential problems.
Benefits of Choosing a Reverse Osmosis Filtration System
A reverse osmosis system offers several benefits beyond providing cleaner, safer drinking water, including:
- Volume: With a reverse osmosis system, you can treat as much water as you need without having to wait for slower processes like repeatedly filling pitcher filters.
- Aesthetics: In addition to reducing a broad range of potential contaminants, RO systems help enhance the taste, odor and appearance of your home’s water.
- Long-term value: High-quality RO membranes and filters are designed for durability, requiring less frequent replacement compared to standard filtration options. Many households also experience savings by reducing or eliminating single-use bottled water purchases.
- Waste reduction: By limiting your reliance on single-use water bottles, you can reduce your environmental footprint. For instance, a household using a Culligan RO system can help prevent the use of more than 2,700 single-use plastic water bottles in just one year.
- Reliability: RO systems address a wider variety of water quality concerns compared to basic filtration options, delivering peace of mind with a reliable, high-capacity solution for your drinking water needs.
What Are the Best Reverse Osmosis Systems?
Not all reverse osmosis systems are designed the same. To ensure your home receives a complete, effective water filtration solution, it’s important to look for key features that indicate quality and performance, such as:
- Multiple stages of filtration: A well-designed reverse osmosis system includes multiple filtration stages, not just the RO membrane. Advanced systems offer additional pre- and post-filtration to address a wider range of water quality concerns.
- Certifications: Third-party certifications guarantee that a filtration system can efficiently and effectively address certain contaminants. The best reverse osmosis systems are tested and certified to NSF/ANSI 58, NSF/ANSI 42, NSF/ ANSI 53, NSF/ANSI 401, NSF/ANSI/CAN 372, CSA B483.1 and NSF Protocol P231.
- Service and support: Choose a provider who will be available throughout the life of your system to provide service and support. They should answer your questions, offer professional installation, recommend maintenance schedules and help simplify your water filtration experience.
Smart Reverse Osmosis Systems
A smart reverse osmosis system comes with additional benefits thanks to a variety of specialized features. For example, some help you track water usage, contaminant reduction, money saved, filter replacement needs and more. The best systems even have a smartphone app for real-time monitoring.
The Best Reverse Osmosis Systems
Culligan’s reverse osmosis systems are designed to make it easy for you to enjoy safer, cleaner water on tap at home. Top systems include:
- Aquasential® Smart Reverse Drinking Water Filtration System: The Aquasential Smart RO is certified to reduce over 90 contaminants with up to seven filtration stages and 14 filter options. Plus, smart technology allows you to track water consumption and contaminants reduced.
- Aquasential® Reverse Osmosis Drinking Water System: Get an unlimited supply of cleaner, safer water with a system designed for easy setup and maintenance. This system offers the same protection as the Smart RO, minus the smart features.
- Aquasential® Tankless Reverse Osmosis System: This unique tankless design delivers the quality and quantity of water your home depends on without taking up extra space under your sink. It includes four stages of filtration and additional options for pH-balanced water.
Water Testing: The Best Way To Determine Your RO System Needs
The best way to choose the reverse osmosis system that’s right for your home is to have an in-home water test and consultation. Test results are generally available in under 30 minutes, and their goal is to reveal key water quality issues. Even if you think your water quality has been consistent for a while, a test can uncover things you may otherwise not have discovered. Most water quality issues actually can’t be seen, tasted or smelled, so testing is always a crucial step.
Professional tests and consultations help you zero in on the appropriate treatment options for your particular needs. For example, a water expert might recommend an RO filter system for your drinking water and a whole home system to prevent iron stains on your tubs and sinks. Tests also tell you your water’s hardness levels and whether you need a water softener.
Reverse Osmosis FAQs
What Is the Lifespan of a Reverse Osmosis System?
The lifespan of a reverse osmosis filtration system depends on two key factors:
- Maintenance: In Culligan reverse osmosis systems, filters can last about one or two years before needing replacement (the process is simple), depending on factors like the type you select and how much water you use. The RO membrane can last up to five years before replacement is required.
- Manufacturing: Selecting a reverse osmosis system from a reliable manufacturer and service partner is important to help keep your system running efficiently and effectively. Culligan designs and manufactures its own systems to maximize lifespan, performance and reliability. Many core parts of Culligan RO systems, including the faucet, tank and other parts of the system, are covered by warranty for 10 years.
Is Reverse Osmosis Water Pure Water?
Reverse osmosis provides a high level of filtration, producing water that is commonly described as purified. However, “pure” water has a specific definition, typically referring to distilled water. Distillation involves evaporating water and recondensing the steam, removing nearly all dissolved substances.
While reverse osmosis systems significantly reduce a wide range of contaminants, they do not achieve the same definition of purity as distillation. For most households, reverse osmosis water offers an ideal balance of cleanliness, taste and convenience — but it is not classified as pure water in a technical sense. (The same is true for most home drinking water filtration systems available.)
Can You Buy Reverse Osmosis Water?
Some brands of single-serve bottled water use reverse osmosis and other treatment techniques. Additionally, if you choose to subscribe to a bottled water delivery service, you may be able to have RO water delivered straight to your home or office (depending on which options are available in your area).
Can You Have a Reverse Osmosis Filter and a Water Softener?
You don’t have to choose between reverse osmosis filtration and softening. These systems often work together to address contaminants and eliminate hard water problems at the same time.
A reverse osmosis system is a single-tap solution that handles contaminants that may impact the taste, odor, appearance or quality of your drinking water. Meanwhile, a water softener is a whole-home system that reduces hardness minerals such as calcium and magnesium that cause buildup on your faucets, laundry, skin and hair, and more.
Can You Use Reverse Osmosis With Any Water Source?
Yes, reverse osmosis systems are suitable for both municipal and private well water, but for different reasons.
If your home uses municipal water, your water supply likely meets federal safety standards. However, those standards are not designed to address every potential contaminant. They are based on levels deemed acceptable for health and what public utilities can reasonably achieve.
Some emerging concerns, like microplastics, pharmaceuticals and PFAS, are not yet regulated or may have pending regulations that take years to implement. Additionally, water can pick up impurities such as lead, iron, sediment or disinfection byproducts as it travels through municipal pipes or home plumbing. Many homeowners choose reverse osmosis filtration to achieve a higher standard of water quality for drinking and cooking.
If you rely on a private well, an RO system can be especially helpful since wells are not regulated or treated by municipal systems. Reverse osmosis provides a reliable option to reduce a broad range of contaminants commonly found in well water.
What Kind of Maintenance Is Required With a Reverse Osmosis System?
As with any water filtration solution, reverse osmosis systems need periodic maintenance to continue operating at peak performance. In general, routine upkeep for reverse osmosis solutions includes replacing filters and the RO membrane as needed. With Culligan reverse osmosis drinking water systems, filters can last up to two years and the membrane lasts 3-5 years.
Additionally, smart technology can let you know via your mobile phone when filters need to be replaced, so you’re not removing them too soon or too late. Most Culligan locations also offer ongoing service programs that make this maintenance easy and hassle free.
Are There Rental or Financing Options for a Reverse Osmosis System?
If you think a reverse osmosis system is the best way for you to treat your drinking water at home, it’s important to consider your financial options. Often, payment approaches are available to fit most any budget.
For instance, if you rent your home or want to try out a reverse osmosis system before you commit to purchasing one, many suppliers will offer you a rental option. Some agreements even include bundled maintenance and support. You may also be able to explore rent-to-own options — just remember to check with your landlord ahead of installing any systems if you don’t own your home.
Financing also is available in many cases. That way, you can start to enjoy fresh, filtered water on tap quickly while completing payments for the system over time.
Enjoy Your Own Reverse Osmosis Water
A reverse osmosis system is a reliable, effective way to address a wide range of contaminants, including those that may impact the taste or odor of your tap water as well as your health.
Ready to enjoy filtered water on demand? Schedule your free, in-home water test and consultation to get started.
*Contaminants may not be present in your water.
**Efficiency is based on 3rd party testing to NSF standards.
