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Reverse Osmosis System vs. Water Softeners: Which One to Buy?

by Carl Jensen

Plumber, Welder, Contractor

> 2 min read

Reverse Osmosis System vs. Water Softeners Which One to Buy

The most convenient and cost-effective water source is the kitchen faucet, but many consumers are increasingly concerned about the additional chemicals and minerals present in their drinking water. 

These substances can have an adverse effect when showering, washing your hands, or even using domestic appliances. The Environmental Protection Agency (EPA) sets maximum safe levels of minerals and chemicals allowable in the public water supply. However, some consumers have concerns these levels may be too high and pose a risk to human health.

If you have concerns about your water quality for health or environmental reasons, you can use a reverse osmosis system or water softener. Depending on your goals, each option provides benefits for consumers.


Why Do I Need to Treat My Water Supply?

Before choosing a water treatment system, you need to identify the problems with your water supply.

Hard water contains high concentrations of minerals such as calcium and magnesium. 

These minerals can cause a chalky white build-up on your surfaces and clog your pipework. They also attach to parts in your appliances that use a water supply, making it harder for them to perform at optimum levels. This drop in performance can lead to increased costs in replacement parts and an increase in your carbon footprint as your appliances use more energy than necessary.

There are additional contaminants in some municipal water supplies such as bacteria, lead, iron, and chlorine. 

Plastics also pose an issue for your household water supply, as their deterioration can not only pollute water with microplastics, but they can also leach BPAs, phthalates, and PFOAs into the water, which are known carcinogens. Unfortunately, many water treatment facilities cannot remove these contaminants adequately.

What is a Reverse Osmosis System?

A reverse osmosis system is one of the most effective methods for filtering your household water. The system uses pressure to force the water supply through several filtration stages, including a semi-permeable membrane. Each stage removes different contaminants. The first action a reverse osmosis system performs is prefiltration. 

The prefiltration stage uses a carbon filter followed by a sediment filter. By removing larger sediment pieces, this initial filtering stage prevents the substances from blocking the reverse osmosis membrane. 

The next step involves passing the water through a semipermeable membrane. This structure can remove microscopic particles; bacteria such as E. coli, salmonella, and shigella; protozoa, giardia; and viruses like rotavirus and hepatitis B. 

At this stage, the thorough cleaning procedure filters metals including lead, chromium, and copper that can pass through systems with a less stringent cleaning methodology. After removing sediment and minuscule particles, a reverse osmosis system sends the clean water to a storage tank until someone turns on a faucet.

There is a final filtration stage in some systems that uses an activated carbon cartridge to remove chlorine to improve your water’s taste and odor.

"A semipermeable membrane can remove microscopic particles; bacteria such as E. coli, salmonella, and shigella; protozoa, giardia; and viruses like rotavirus and hepatitis B." 

What is a Water Softener?

Hard water contains high levels of calcium and magnesium ions that lead to mineral build-up, damaging pipes, appliances, and irritating skin. There are various types of water softeners available, including ion exchange and salt-free units.

Ion exchange water softeners are the most common style and use a bed of resin beads charged with sodium ions. When the positively-charged magnesium and calcium ions come into contact with these negatively charged beads, they attach to the bead’s surface. To maintain balance, the beads release negatively-charged sodium ions into the water supply.

A salt-free water softener doesn’t remove the mineral ions from the water. Instead, it breaks them into smaller particles using a Template Assisted Crystallization (TAC), so they pass unobstructed through the plumbing.

Reverse Osmosis Systems vs. Water Softeners

It can be challenging to choose between a reverse osmosis system vs. water softeners. The most suitable choice depends on your water quality, so the first step is to identify which minerals, microorganisms, metals, and chemicals are present. 

Your water supplier must provide you with a report by July 1st each year. This document should advise which contaminants are in your domestic water supply, the safe permitted levels, and the potential health effects. However, you can also appoint a contractor to test your water and provide an independent report if you still have concerns.

Benefits of Reverse Osmosis Systems

If you are aware of unsatisfactory levels of contaminants such as chlorine or heavy metal in your water supply, opt for a reverse osmosis system. An RO system provides your household with clean, safe drinking water.

When using a reverse osmosis system, you may also notice your water tastes better because it contains fewer chemicals. There is no need to buy expensive bottled drinking water, potentially saving you money over an extended period.

Read More: Getting Rid of Rotten Egg Smell On Water

Benefits of Water Softeners

A water softener won’t remove harmful contaminants from your water, so these units are best suited to households with a clean but hard water supply. These units are more affordable than an RO filter, and there is no need to replace the filters. You only need to add more salt to a water softener to recharge the resin beads with powerful negative sodium ions.  If you have a salt-free water softener, you don’t need to recharge the beads at all. 

Water softeners offer a cost-effective method of removing harmful minerals from your water, helping to protect your pipework, domestic appliances, and even your skin. They require little maintenance and perform efficiently for many years. 

The Bottom Line

Deciding whether to buy a reverse osmosis system or a water softener comes down to your water supply quality and desired goals, as each system performs a different function. However, you can use both systems simultaneously. Initial contact with a water softener in your plumbing system removes the magnesium and calcium ions. 

When the water reaches the reverse osmosis system’s semi-permeable membrane, it removes any remaining impurities. By installing a reverse osmosis system at a faucet for drinking and cooking water, you can get clean water and minimize damage to your plumbing from mineral deposits.

Carl Jensen

About the Author

Carl Jensen is a plumber with over 50 years of experience in the industry, as well as related jobs like underwater welding. He runs a successful plumbing practice in Tampa, Florida, and contributes his plumbing expertise to our DIY articles, and helps to fact check and consult on most of our other stuff to boot.