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Reverse Osmosis vs Water Softener: What to Rely On?

Reverse Osmosis vs Water Softener
Written by Jenny Molin

What Is a Reverse Osmosis System?

This system purifies water by removing unwanted contaminants and molecules.

How Does It Work?

It forces the water across the semi-permeable membrane with a high-pressure pump to increase the pressure on the salt side of the system.

Reverse Osmosis Work

Does It Help Soften Water?

Yes, it helps soften water but constant filtering will result in replacing the membrane more often.


  • Going green

RO is a safe, eco-friendly alternative to bottled water. The bottled water industry is notorious for lack of regulation and is not required to disclose where the water originated, how it has been treated or what contaminants it contains.

Reverse osmosis means you can feel assured of your water in your own home whilst also cutting down on waste plastic bottles.

  • Contaminants removed

You can remove more than 90-99.99% of all the contaminants, including minerals from the drinking water supply.

  • Purest cooking

RO remove more contaminants and minerals than any other filtration method. This helps ensure that your food is prepared in the best way possible.

  • Sodium removal

Some water softener systems might be criticized for producing water with too much sodium in it, which is not good for people on sodium-restricted diets.

To counter this, an RO system effectively softens the water by removing sodium content completely.

Disadvantages of reverse osmosis systems

  • Quite costly

The quality and capability of a reverse osmosis system is reflected in the price. A high-end brand will cost more but should have better contaminant removal capabilities and ease of maintenance.

However, all systems will need their filters regularly replaced which is an ongoing cost to be considered. Prices can range between $200 and $4000+ depending on whether you opt for a domestic or a commercial unit.

  • Pressure loss

For an RO system to run perfectly, the optimum water pressure is 60 PSI. If your water pressure is below 40 PSI then you will need to install a booster pump to make your RO system effective.

The average house will range between 30 and 80 psi so if you notice your pressure dropping after installation it may well be that you didn’t have sufficient pressure to start with and will need the booster pump.

  • Wastewater

Most RO systems with a single membrane work with a product to wastewater ration of 4:1. While there are ways in which wastewater can be reduced, some is inevitable.

However, some homeowners are creative with the excess water so it doesn’t become waste. The obvious uses are for cleaning your crockery, cutlery, floors, bathroom, kitchen, or car, or why not water your plants?

  • Patience required

An RO system is slow and usually takes one minute to produce two to three ounces of water. A standard glass of water would take about five minutes to fill.

  • Essential minerals removed

Some essential minerals contained within water are also removed. The molecules of these minerals are larger than water molecules and so the system filter prevents them penetrating the membrane.

However, the World Health Organization clarified that the majority of healthy minerals the human body needs come from food or supplementary sources and not from tap water.

  • Water-Borne viruses NOT removed

According to a study conducted by the Pune-based National Institute of Virology, most purifiers do not completely eliminate water-borne viruses like Hepatitis E.

  • Membrane repairs

The two main causes of membrane breakage in RO systems are chemical damage and membrane ballooning.

Chemical damage is caused by the external build-up of the filtered molecules due to lack of regular maintenance and membrane ballooning occurs during system shutdown because of excessive permeate backpressure.

This causes the membrane to stretch out of shape and intrude into the feed channels impeding flow and pressure.

What Is a Water Softener System?

A water softener is a whole-house filtration system that removes hardness-causing magnesium and calcium minerals from your water through a process called ion exchange.

How Does It Work?

It removes magnesium and calcium through a process of ion exchange turning hard water to soft.

Water Softener Work


  • Softens water

Hard water contains vast quantities of magnesium and calcium which often clogs pipes and makes it difficult for detergent and soap to dissolve in water.

Water softening removes the magnesium and calcium that causes the water to be hard.

  • Ease of use

Due to the softening of the water, with the replacement of magnesium and calcium, it will react better with soap and detergent and leave less scale in plumbing.

  • Appliance protection

Hard water is the main cause of scale-ridden appliances. Using a water softener will preserve those appliances and prevent the constant need for repair.

  • Plumbing protection

Due to the buildup of scales, if unmaintained, hard water could put the entire plumbing system under pressure and ultimately destroy it. A water softener system could prevent this costly repair.

  • Toxins removed

Water softeners also remove a slight amount of toxins like ferrous or dissolved iron currently in a soluble state. The iron causes the water to appear darker and leaves stubborn stains on your sinks, bathtubs, and toilets.

  • Whiter whites

Soft water allows soaps and detergent to work correctly whereas hard water is resistant and prevents the proper cleaning process.

It is also softer on the skin and will not irritate in the way that hard water does.

  • Softer clothes

Hard water causes laundry to be stiff and hair to be dry as it reduces the reaction of water and soap. What this really means is that nothing is cleaned properly.

  • Mineral balance

Water softeners replace magnesium and calcium with sodium. Sodium aids the body in controlling the fluid balance, sending nerve impulses, and balancing other minerals found in water.

Also by significantly reducing the levels of calcium and magnesium in the water, it lowers their concentration to levels that may benefit one’s health.

  • Eczema relief

Research has shown that hard water is a possible cause of eczema in children. Using a water softener could prevent the development and irritation of eczema thus alleviating the non-stop desire to scratch.

  • Expensive alternatives

Potassium chloride is the alternative to sodium or salt pellets, but they are expensive in comparison. For example, a bag of salt costs between $4 and $6 whereas a bag of potassium chloride could set you back up to $30.


  • Poor farming

Softened water is not suitable for irrigation as it lacks magnesium and calcium. The removal of these elements causes alkali soils to develop which are difficult to settle due to their bad structure.

  • Matter of taste

The resulting product of soft water is not to everyone’s taste. It has been described as slimy and slippery. It is all preference.

  • Costly installation

Water softeners are not cheap, and costs could rise to $2,000 for installation. Routine maintenance is also required as the beads of resin will run out and of sodium to balance the magnesium and calcium.

  • Sodium overload

The ion exchange process of water softening can result in soft water that is higher than normal in sodium content. The daily recommended intake for a healthy person is 2300 mg per day. Actual intake could increase to 3500 mg per day from soft water. So this is something to be considered.

  • Environmentally unfriendly

A major drawback of salt-based ion-exchange water softeners is that they produce chloride and discharge it into the septic or sewage systems

Chloride often ends up in rivers, lakes, and streams since facilities aren’t designed to remove it. High levels of chloride in the environment are toxic to the aquatic creatures.

  • Dietary interference

Some diets may need supplements found in hard water but removed from soft water such as magnesium and calcium. These minerals being removed may cause digestion and health concerns for those who need them.

Reverse Osmosis vs Water Softener: What Are the Differences?

  • Water output

An RO system is designed for the purification process and water softeners operate in the reduction of hard water.

  • Water treatment process

The RO process reduces impurities such as salt, minerals, and toxins. A water softener exchanges ions which extract minerals such as magnesium and calcium and put sodium or potassium in their place softening your hard water.

  • Water taste

An RO system reduces contaminants that can cause your water to taste unpleasant. A water softener replaces the calcium and magnesium ions with sodium which you may then taste. An RO system will therefore give you the purer tasting water.

  • System maintenance

While the reverse osmosis system will soften water in addition to filtering it, constantly filtering hard water will wear out the membrane faster and waste a lot of water. So, WS systems are often a more economical solution in the long run to water hardness.

  • Water quality

An RO system will supply your family with high quality drinking water by eliminating most impurities, including cadmium, hydrocarbons, pesticides and sulfates where a water softener will replace the calcium (Ca) and magnesium (Mg) with sodium (Na) or potassium (K), thinning it and improving it’s cleaning properties.

  • System efficiency

RO systems are less efficient than water softeners. That is why they’re usually installed at a single point-of-use, like a kitchen sink, rather than being used for the whole house.

Why Get a Reverse Osmosis System?

A reverse osmosis system is what you should be purchasing if you wish to be drinking the purest water from your tap and have the patience to wait for it.

Why Get a Water Softener System?

A water softener system is what you should get if you live in a hard water area or have trouble with hard water in your laundry, plumbing or cleaning.

Why Not Get Both?

To get the best quality of water you can, many people opt to install both systems.

A water softener and the reverse osmosis system make great bed fellows because the softener removes the minerals that make the water hard and a reverse osmosis system will give your household outstanding drinking water by removing the impurities.

Let the water softener service the entire house whilst the reverse osmosis system focuses on the kitchen tap.


Can a reverse osmosis system remove hard water?

Ans. A reverse osmosis system can remove hard water but if you were to use one for all the plumbing in your house then you would find yourselves with pressure issues and you would need a lot of patience to wait for the tank to fill … if it ever did.

What if I forget to change the filters of my reverse osmosis system?

Ans. If you forget to change the filters on your reverse osmosis system then it will soon stop working correctly. It may become clogged with residue of chemical molecules or misshapen and clog the pipes. Either way you will lose the much-needed pressure.

How long does a water softener system last?

Ans.  A well-maintained water softener can last between 10 and 15 years. However, this depends on factors like the volume of water going through the system and the hardness of this water. The higher concentrate of minerals means it will be working harder every time.

About the author

Jenny Molin

Interior Design Artist

Hello, I’m Jenny. I’ve been an interior design artist by profession since my B.S. in Interior Design. I’m a minimalist and prefer to save space when choosing fixtures, sinks and fittings. My style tends to make the most out of the least amount of space. The idea behind every interior design project is unique and it reflects personal style, taste and tradition. I’ve learned more when working than I ever did while I was studying in college. I worked in more than 12 hundred households all across the US and got positive feedback. I’ve been working with FaucetsReviewed as one of the founding members and regularly contributing to the site via testing and reviewing various interior fittings and fixtures.

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