Reverse Osmosis vs. Distilled Water

There are many water purification options on the market. Some water softeners are installed as part of the home water system, and others on the faucet or as a jug in the fridge. It can be difficult to know which is the best for you and how they compare without becoming lost in marketing talk or scientific jargon. 

Two of the most common purification methods are reverse osmosis and water distillation, each helping to remove contaminants in substantially different ways. To help you land on the best way to clean your water. Let’s explore reverse osmosis vs. distilled water and help you land on the best option for you. 

By Method: Reverse Osmosis vs Distilled Water

How water is treated makes a difference in contamination levels, what can be removed, and how it tastes. While both reverse osmosis and distillation produce very clean water without remineralization, they are very different processes that may be preferred for your home use:

Reverse Osmosis Process

Reverse osmosis uses membranes to filter out water. Typically four fine membranes that water passes through to remove any contaminants or other impurities at a microscopic level. Water is pushed through different membranes or filters using a high-pressure pump, such as a sediment filter and carbon filter, before passing through the semipermeable membrane which removes up to 98% of dissolved solids. 

The process happens in this order:

1. Prefiltration: typically the carbon and sediment filter to remove sediment and chlorine.
2. Water is pushed through the reverse osmosis membrane where dissolved particles are removed
3. Water flows into a storage tank where it sits until needed
4. When water is turned on at a drinking water faucet, the water flowing out of the tank goes through a postfilter for one last filtration before flowing from the faucet.

    

Distilled Water Process

Water distillation is one of the oldest ways humans have cleaned their water. It’s an effective and quick process that has been around for centuries. The water is heated to a boil and the vaporized water is then separated from contaminants in it. 

The process works in this order:

1. The water is heated to above 212 degrees Fahrenheit (boiling point for water) which removes many harmful contaminants and microorganisms. Keep in mind that water begins to evaporate at a much lower temperature than 212 degrees, meaning that the majority of contaminants will be left behind. 
2. The steam rising from the boiling process travels out of the container and into a tube, reducing the steam’s temperature and producing condensation. As the steam turns back into water droplets, it will be free of most of the impurities and contaminants originally there. 
3. Once the water has been fully condensed, the droplets fall and water is collected. Keep in mind that commercially distilled water uses carbon post-filters to remove any additional contaminants found after the distillation process is finished, mainly volatile organic compounds.
   

Comparing Reverse Osmosis and Distilled Water

As reverse osmosis and water distillation are different processes, you’d be correct in assuming they remove different things or one does more than another. 

Take a look at the chart below and see what contaminants each process does and does not remove:

Contaminant Removal