As someone interested in how to remineralize RO water, you most likely know that reverse osmosis (RO) is a best-in-class solution for drinking water purification. RO filtration systems are highly effective at removing numerous contaminants from your water, but they also reduce naturally occurring minerals that give water its refreshing, crisp taste. That's where RO water remineralization comes into the water filtration process.
What Is Reverse Osmosis Water Remineralization?
The signature part of the RO water filtration process allows small water molecules to pass through a semi-permeable membrane, while filtering out larger contaminant particles and molecules, including naturally occurring minerals dissolved in the water. Some of those minerals can be toxic in water (e.g., arsenic), and excess amounts of others (e.g., calcium) can cause limescale buildup in small appliances, such as a kettle or coffee machine. While too much of any mineral can cause water to taste unpleasant—salty, bitter, or metallic, the right mix and amount can actually enhance the taste, giving it more character.
After the RO water filtration process is complete, water remineralization is a process that infuses beneficial alkaline minerals, such as calcium and magnesium, back into the water. Calcium, magnesium, and a variety of other minerals are electrolytes, like those in common sports drinks. When they're added via remineralization, though, it's at a lower concentration. The remineralization process also typically elevates the water's pH, a measure of how acidic or basic/alkaline it is.
The pH of pure water is 7. The pH level increases when alkaline minerals (e.g., magnesium) are added. However, if you add an acidic substance—a splash of lemon or lime juice in your glass, for example—the pH level will decrease.
How Reverse Osmosis Remineralization Works
RO water filtration systems typically include three or more phases of filtration to purify the water: 1) a sediment filter, 2) a carbon filter, 3) an RO membrane, 4) an optional advanced carbon filter (often included in high-end RO filtration systems), and 5) a (usually optional) remineralizer. Some systems may also include an ultraviolet (UV) water treatment stage as a final step.
Depending on the manufacturer, the remineralizer cartridge includes small mineral balls or minerals blended into a carbon filter. As filtered water flows through the cartridge, good-for-you minerals are infused into it. The result is better taste and enhanced pH of your water.
Is Reverse Osmosis Remineralization Right for You?
Ultimately, the decision to add a remineralizer comes down to personal preference and taste. Generally speaking, remineralization after the RO process adds alkaline minerals at a level that improves taste for drinking, making coffee, and cooking—without increasing limescale buildup in your appliances.
Taste is highly subjective, though. Remineralized water might taste flavorful to one person, but it could be too intense for someone else. So how do you decide? To get a feel for what you like best, conduct your own taste test of different bottled water brands. Dasani and Aquafina bottled waters contain few, if any, minerals—a level that would be similar to water that's been through the RO process. In contrast, brands like Smart Water and Mountain Valley include a low baseline of minerals, which would be comparable to RO water that's been remineralized.
Comparing RO Water Filtration System Options
If you opt for remineralization as part of your RO water filtration system, keep these considerations in mind as you research RO system options:
- Which Minerals Are Included: Check the remineralizer cartridge information to see which minerals are included and how they're sourced. For example, the Delta® Clarifi™ RO Remineralization Cartridge includes naturally sourced calcium and magnesium.
- Cartridge Installation and Replacement: Read the maintenance and installation instructions to find out how the remineralizer cartridge is installed and how easy it is to replace .
- Cartridge Lifespan: Check the specifications to determine how frequently the manufacturer recommends replacing the remineralizer cartridge (based on capacity and/or timeframe). Ideally, the timing will be in sync with carbon and RO filter replacements, making it easier to maintain your entire RO water filtration system.
- Certification to Industry Standards: Look for certification of replacement cartridges to National Sanitation Foundation (NSF) standards, including NSF-42 and NSF-372 for material safety, structural integrity, and lead-free requirements . Unlike complete RO filtration systems, there are no industry standards for performance or taste.
- Cost to Own: Include the cost of replacement cartridges in your calculations. Keep in mind that cartridge lifespan can have a significant impact on cost. For example, a $35 cartridge that needs to be replaced annually will cost $210 over 6 years, whereas a $50 cartridge that is replaced every 2 years will cost $150 during the same timeframe. Shipping fees, if applicable, should also be factored in.
Want to know more about RO water filtration? Visit our water filtration blogs to learn why it's considered the gold standard in drinking water filtration.
The Delta® Clarifi™ Tankless Reverse Osmosis Water Filtration System provides six stages of filtration, plus a remineralization option, to filter out 90+ contaminants from drinking water. The remineralizer cartridge includes a custom blend of calcium and magnesium designed for better taste. See how we provide water filtration you can trust.
