Reverse Osmosis Water pH – Does RO water need to be remineralized?

person holding water glass

RO Water pH

The filtration process of reverse osmosis is non-selective, which means that it will remove non-harmful minerals like potassium, magnesium, and calcium along with the chemicals and heavy metals that we want to be removed from drinking water.

Pure water has a pH of 7 and reverse osmosis water typically has a pH range of 5-7. Generally, the pH value of water is recommended to be between 6.5 and 8.5. However, this recommended pH range does not mean that people do not consume beverages that have a lower pH, beverages like soft drinks (1-2.5pH) and coffee (4-5pH) fall below that recommended range.

Alkaline vs Remineralization

Alkalinity is a measure of the capacity the water has to neutralize acids. Alkalinity in water is measured in milligrams per liter (mg/L) or parts per million (ppm) of calcium carbonate (CaCO3). Water with a pH greater than 7 is considered alkaline.

Remineralized water is water that has had some mineral content added back, usually after filtration such as reverse osmosis. The minerals added back to the water can vary slightly based on the type of remineralization filter. The most common remineralization filters are calcite (calcium carbonate) filters and magnesium and calcite filters. When low pH or acidic water comes into contact with calcite, the water slowly dissolves the calcite to raise the pH level to neutral or above (7-9).

Using a remineralization filter with a reverse osmosis system is not a requirement to enjoy reverse osmosis water, it comes down to personal preference. Simply put, some people find remineralized reverse osmosis water tastes better than non-remineralized reverse osmosis water.

Olympia Water Systems offer a 100% calcite (calcium carbonate) Alkaline/Remineralization filter that is available as part of our 6-Stage alkaline system (OROS-80-ALK) or as an add-on kit (OROS-ALKKT) to add the calcite remineralization filter to any existing reverse osmosis system.