Saveourh2o is supported by its audience. When you purchase via our links, we may get a commission. Learn more

Reverse Osmosis vs Water Softener – Which One is Better?

Writen by Ronald Brown

Fact checked by Natalie Bridges

Reverse Osmosis vs Water Softener

Are you confused about which between reverse osmosis system and a water softener you should get for your home? Understanding the reverse osmosis vs water softener paradigm should help you decide which water treatment technology to use.

Both technologies remove minerals present in your water. However, one can also remove other contaminants or impurities for safe, clean, and pure water. While the other one can augment the water contaminant-removal capabilities of the other system.

So, which should you choose?

Table of Contents

Water Softeners And Water Softening


Hard water contains metal ions, such as calcium and magnesium. These ions clump together to create limescale in the inner surfaces of water fixtures and appliances. It reduces water heater efficiency, making it harder to heat your water.

Hard water also shortens your water filter’s lifespan. Calcium can also react with detergent molecules to form soap scum. You may need more detergent or soap to do your laundry or clean your hands. Doing so wastes critical resources.

From US Geological Survey, soft water contains less than 60 mg/L of calcium carbonate. Water containing 61-120 mg/L of calcium carbonate is moderately hard, 121-180 mg/L of calcium carbonate is hard, and more than 181 mg/L of calcium carbonate is very hard.

The Water Quality Association has a slightly different classification measured in grains per gallon (GPG).

  • Soft water = less than 1.0
  • Slightly hard water = 1.0- 3.5
  • Moderately hard water = 3.5 – 70
  • Hard water = 7.0 – 10.5
  • Very hard water = 10.5

If you want to know your area’s water hardness level and others in the US, you might find this map helpful.

Water softeners work to reduce calcium, magnesium, and other metals or ions present in water, the chemicals that make water hard.

Hard water goes into a tank with a resin containing sodium or potassium ions. The resin has a greater affinity or attraction for calcium, magnesium, and other ions.

When hard water makes contact with the resin, it releases sodium ions and allows calcium and magnesium to bind to the freed sites.

Removing these hardness minerals from the water saves your water-using appliances and water fixtures from limescale formation and buildup. You ensure better performance while also enjoying cleaner dishes and utensils and more pleasant showers.

Reverse Osmosis Water Filtration


To understand how reverse osmosis works, let us begin with an understanding of what a solution is. Solutes and a solvent make up a solution. Our water contains impurities, dissolved particles, and substances other than water, forming the solutes in the solution.

In conventional osmosis, water molecules move from a solution with more water (more solvent than solutes; a dilute solution) to a solution with less water (less solvent, more solutes; a concentrated solution).

Reverse osmosis works the opposite. A mechanism pushes water molecules from a concentrated solution to a diluted solution. In effect, reverse osmosis removes almost all dissolved solids and other impurities.

You might ask if total dissolved solids are bad for you. While TDS is not a health hazard, unusually high levels often indicate harmful contaminants in the water.

According to the World Health Organization, acceptable TDS levels are between 300 and 600 mg/L. Total dissolved solids of more than 1,200 mg/L are unacceptable.

Surprisingly, a reverse osmosis system could also remove water-hardening minerals. The only substances that a reverse osmosis system cannot remove are dissolved gases. Water Research provides a list of what a reverse osmosis device can and cannot remove.

A reverse osmosis filtration device is part of a larger water treatment system. A pre-filter removes sediments and an activated carbon filter eliminates other particles, including chlorine odor and taste. Most products also have a post-treatment filter.

There are also RO treatment systems that include a deionizing mechanism that softens the water. Deionization filters release negatively-charged ions into the water to bind with calcium and magnesium.

If you are interested in such a product, I suggest you check out the iSpring RCC7D.

One downside to using an RO system is it also removes beneficial minerals. However, there is an interesting article about reverse osmosis drinking water and how your body can compensate for any electrolyte imbalances.

Should You Get a Reverse Osmosis Filtration System Instead of a Water Softener?

Given that an RO system also removes water-hardness minerals, it would be safe to assume that you can do away with the water softener. However, you should know that very hard water can overwhelm your reverse osmosis filtration system.

Hardness minerals can form limescale on the sediment pre-filter, reducing your water filtration’s contaminant-removal capabilities. It can also reduce your RO filter membrane’s performance.

The ideal setup is to combine a water softener with a reverse osmosis system to provide you with the following benefits.

It Improves water quality

Reverse osmosis systems remove impurities, making your water more pleasant and safer to drink and turn into refreshing beverages. Making crystal clear ice cubes for your wine is also possible.

It Extends RO System lifespan

Removing hardness minerals before the water reaches the RO membrane prevents limescale formation in this part of your water treatment system. It allows the RO filter to work optimally, giving your family the purest water they can drink.

Increases cost savings

RO systems are pretty expensive. Adding a water softener to your RO system extends its service life and that of other water appliances. You will have less frequent RO membrane replacements, water fixture maintenance, and water appliance repairs.


The reverse osmosis vs water softener debate continues to baffle many homeowners. It is clear that no single water treatment technology effectively removes water contaminants as a combination of at least two systems.

A water softener protects your water heater, filtration system, and other water appliances and fixtures from limescale formation. On the other hand, an RO system provides you with pure and safe drinking water.

Getting the iSpring RCC7D water filtration system offers you the best of both worlds and more.

5/5 - (1 vote)