Reverse osmosis (RO) and water softeners are both water treatment solutions, but they serve different purposes. Whereas reverse osmosis reduces a wide range of contaminants in drinking water, softeners address hardness minerals like calcium and magnesium.
At Culligan, we know homeowners want water that’s clean, safe and reliable. That’s why it’s important to understand how these systems work, what issues they solve and when they’re best used together.
This guide breaks down the differences between reverse osmosis and water softening, explains the benefits of each and helps you decide which solution — or combination — is right for your home.
What is reverse osmosis?
In reverse osmosis the filtration system forces water through a semipermeable membrane. This RO membrane acts like a net, catching a wide variety of impurities — including particles so small that you can’t see them.
A reverse osmosis system often combines multiple methods into one comprehensive treatment solution. That means in addition to the RO process, you get additional filtration stages all working together to address water quality issues such as:
- Chlorine
- Viruses
- Bacteria
- PFAS (forever chemicals)
- Nitrate
- Copper
- Lead
- Microplastics
- Total dissolved solids (TDS)
- And more
This kind of water treatment system is often more comprehensive than fridge or pitcher filters — which tend to target fewer contaminants.
Explore water filtration solutions.
What is water softening?
Water softening removes the excess calcium and magnesium that cause hard water. Hard water, which is broadly common across North America, causes a mineral buildup that can lead to spots on dishes and shower doors; dry, dull hair and skin; stiff, faded laundry; and even lower efficiency or breakdown of water-using appliances.
Here’s how water softening works, using a process called ion exchange: Your water flows through a tank containing tiny resin beads, which are negatively charged. The positively charged calcium and magnesium ions are attracted like magnets and trapped on the resin beads while the rest of the water flows through freely.
Your water softener also includes a second tank called a brine tank. This is filled with a salt solution that rinses the mineral ions off the resin so it can continue to work effectively. Some water softeners do this at regular intervals or based on how much water has flowed through the system. For maximum efficiency, the best water softeners use technology to monitor the condition of the resin and only regenerate as needed.
Although softening is a type of water treatment, it isn’t the same as filtration. Similarly, while some water filtration systems may target minerals, they use different processes and aren’t considered softening solutions.
Explore water softening solutions.
Reverse osmosis vs. water softening: Does reverse osmosis soften water?
No. A reverse osmosis system filters drinking water at a specific tap, but it does not soften household water the way a dedicated water softener does. Instead, RO uses a semipermeable membrane to reduce dissolved solids (including some calcium and magnesium) for cleaner-tasting water at the faucet, but it doesn’t perform ion exchange or address scale throughout the home.
A water softener treats the entire water supply, helping prevent scale, soap scum and mineral buildup on fixtures and inside water-using appliances.
Here’s a closer look at how the two systems compare:
Processes
One of the main differences between reverse osmosis and water softening is the method used to achieve the desired result. RO works almost like a net to “catch” and filter out contaminants, while the latter works more like a magnet to attract and trap hardness minerals. Similarly, RO uses a semipermeable membrane while softening uses resin beads.
Another important difference is that reverse osmosis doesn’t have a regeneration phase. Unlike the resin beads in a softener, an RO membrane doesn’t require frequent rinsing; instead, an annual system sanitization is recommended, along with replacement of the RO membrane as needed — and the best membranes can last up to five years.
Target areas and results
RO is all about addressing impurities. This can include noticeable contaminants like chlorine with its swimming pool odor or iron with its metallic taste, but it also targets potentially harmful substances you might not even know about — such as lead and forever chemicals.
That means reverse osmosis has two kinds of results. First, it helps address the health risks that could come with certain contaminants (and also allows you to skip the plastic waste of single-use bottled water). Second, it fixes aesthetic water issues such as unpleasant tastes and odors.
Meanwhile, softening specifically focuses on alleviating the pain points of hard water, targeting the excess calcium and magnesium that cause it. When you remove these components from your water supply, the resulting soft water helps prevent buildup that could corrode your pipes, damage water-using appliances, stick to your bathroom fixtures and even make your hair dry out.
Costs
The cost of a reverse osmosis filtration system depends on several factors, including the number of filtration stages, third-party certifications, smart features and overall design.
One of the factors in determining the cost of a water softener system is its capacity. That’s because the harder your water, the harder the system has to work to complete the softening process. Other factors impacting cost include available features, how efficiently the system operates and whether any other types of filtration – such as for common issues like chlorine or iron – are included.
Features
Both Culligan reverse osmosis systems and water softeners can be equipped with smart technology, allowing you to connect to Wi-Fi and manage settings, performance and alerts directly from the Culligan Connect app.
Water treatment solutions: Softening plus filtration
While a water filter isn’t the same thing as a water softener, these two solutions are better together. Although they treat separate issues, softening and filtration are complementary tools.
That’s because they each focus on different but common water problems. Reverse osmosis helps improve the taste, odor and quality of your drinking water, but it won’t prevent the hard water spots left on glasses and fixtures. Water softening, on the other hand, helps protect your home and your hair and skin from the effects of excess calcium and magnesium, but it doesn’t reduce other contaminants.
The key to getting the most out of these two solutions is twofold:
- Find out what you need each system to do.
- Choose systems that complement each other.
The first step is to start with a professional water test. This will show what’s in your water, from hardness levels to potential contaminants. With expert guidance, you can decide which systems are right for your household and how they’ll work together. In the end, it’s not about a “one-size-fits-all” approach — it’s about creating the right solution for your unique water quality.
Schedule your free water test.
Soften and filter your home’s tap water
There’s no need to choose between softening and filtration. If you want the best results, let these treatment solutions team up to address a wider variety of water problems — from tastes, odors and health concerns to water spots and mineral buildup.
Remember, it all begins with your free, in-home water test and consultation. Schedule yours today.
