With more than 30 years’ experience in the residential and commercial water treatment space, Mark Nelson is a Class 1 Drinking-Water Operator and a CBWA (Canadian Bottled Water Association) Certified Plant Operator. As founder and president of Nelson Water in Ottawa, Mark focuses on dealing with challenging water treatment system designs for problem water. He also heads the largest water bottling plant in the city of Ottawa with a delivery network throughout the Valley.
Many people are curious about drinking demineralized water, but there is a lot of conflicting information on this topic and it’s hard to make an informed decision. In a nutshell, demineralized water has most or all of the mineral content removed leaving behind “pure water”. Demineralized water is used in a number of different commercial and industrial applications but is it better than tap water? In this article, we will examine demineralized water in more detail to help you make the best choice to meet your needs.
A Brief Primer on “Standard Tap Water”
Of course, the actual makeup of your tap water can vary depending on where you live. But, there are commonalities and it is a good idea to understand what is in your tap water before you think about removing minerals. We will focus on a residential application to keep things simple, but the main thing you need to know is that domestic tap water contains salts, minerals and certain other contaminants. Many minerals are added naturally when the water passes through various strata of rock, soil and sand. Water is a solvent, it can dissolve many materials and add them to its makeup on its journey to your home. These minerals are not removed at the water treatment plant, and if you want to get rid of them, you must take action yourself.
What is in the Tap Water?
The exact mineral and salt content dissolved in your drinking water will be determined by the types of rock and soil it passed through. As an example: if you live in an area rich in limestone deposits, you will probably have high concentrations of calcium carbonate. Water tends to pick up a variety of materials, including: salts, minerals and even metals. These materials are collectively referred to as Total Dissolved Solids or TDS.
If you’ve heard of TDS before, you may already know that it’s associated with hard water that can cause scaling in your water using appliances and plumbing pipes. The salts and minerals found in your tap water can damage your coffee pot, dishwasher, washer and even your water heater. You may see white/gray scale developing on heating elements and it accumulates inside your plumbing pipes too. This can lead to an earlier than expected failure, lowered water pressure and frequent repairs.
The scale formed with mineral rich water is hard to clean away and it always returns until the root cause is dealt with. The mineral ions also interfere with the formation of soap suds which to a certain extent nullifies the cleaning power. Many people compensate by adding more soap or detergent, but this makes little difference. The material left behind is soap scum that is tough to clean and it’s a major breeding ground for bacteria. Removing the minerals and making the water softer and easier to use tends to boost the cleaning power and you don’t need to use as much soap.
Demineralized water is often used in industrial processes to protect sensitive equipment. It’s also used to change the pH level in soil and even to produce pharmaceutical products. This is possible because demineralized water has a neutral pH level that is important when you need better control during medicine production, agriculture, and other critical processes.
How is Water Demineralization Achieved?
There are three main demineralization methods in use today. They are; deionization, distillation, and reverse osmosis (RO). Both deionization and distillation are used in agriculture and industry, but they are not a good fit for your home. The RO process is used in both residential and commercial applications, and it works well in both settings. To put the three processes into perspective, let’s take a brief look at how they work:
Deionization: During this process, water is run through a pair of special resins that are charged differently. The first is a negatively charged cation resin, and the other is a positively charged anion resin. The resins act as exchangers by attracting salt and mineral ions to remove them. This process may need to be repeated many times to get the water purity to the standard required. This is an effective way to remove mineral content, but it cannot remove microorganisms, such as bacteria, viruses, protozoa, and cysts.
Distillation: This is an ancient process that has been used to purify water for thousands of years. The water is brought to the boil, the steam produced is captured, condensed back into clean water, and collected. Because the water is changed from its liquid state to a gas (steam) and then back again, the minerals and salts are removed. As an added bonus, many of the microorganisms in the water are made inert when the water is boiled. But, distillation cannot remove organic compounds, chlorine, chloramine, or toxic heavy metals. Distilled water is pure, but a lot of energy is required to heat the water for a long period, and a still takes up a lot of space. These drawbacks make distillation an impractical choice for residential purposes.
Reverse Osmosis (RO): Reverse osmosis is a purely mechanical filtration method that captures the contaminants and then only allows the water molecules to pass through. At the heart of the system is a semi-permeable membrane with tiny pores, the water is forced through the membrane under pressure, and the contaminants are left behind. Periodic rinsing of the membrane flushes the contaminants into the drain making RO water very pure. The only real drawback is that the process takes a while, but the water is stored in a clean tank for ready access when you need it.
If you want demineralized water for drinking and cooking in your home, the best option is a RO system. You can get a point-of-use system installed at your kitchen sink for pure water that’s ideal for drinking, making beverages, cooking, making ice, and more. To remove the water hardness and protect your appliances and plumbing system it’s a good idea to install a water softener. If you want to learn more about these clever filtration systems for your home, contact your local water treatment specialist today.