Sodium is a common element in the natural environment and is often found in food and drinking water. In drinking water, sodium can occur naturally or be the result of road salt application, water treatment chemicals or ion-exchange water-softening units. Sodium levels may also vary in bottled water and carbonated water, depending on the brand.
The human body needs sodium in order to maintain blood pressure, control fluid levels and for normal nerve and muscle function. Sodium in drinking water is not a health concern for most people but may be for someone with specific health issues that require them to be on a sodium-restricted diet. It may also be a concern for infants who are being fed infant formula and/or any other food or beverages prepared with tap water that is connected to a water softener.
Guidelines for drinking water quality
Public drinking water systems under the Safe Drinking Water Act are required to sample for sodium on a regular basis and report to the Medical Officer of Health when sodium levels exceed 20 mg/L. This information is made available to local physicians in order to help people on sodium-restricted diets control their sodium intake. Although less than 5 to 10% of an adult's daily intake of sodium typically comes from water, you should consult your family physician if you are on a sodium-restricted diet and have concerns about the level of sodium in your drinking water.
If you are interested in receiving more information about public drinking water systems and their sampling results, please contact your local municipal drinking water provider.
If you own a private well, you should consider testing your water for sodium at least once every five years, especially if the well is located near a roadway where road salt is used.
Water softeners and treatment devices
Most water softening devices use ionic exchange to replace calcium with sodium. While this reduces the hardness of your water, it may add significant amounts of sodium. Softened water should be avoided for infants as it can contain too much sodium for infants. If you need a water softener, consider having a separate line for drinking and cooking, which bypasses the water softener.
Water treatment devices may also be installed at the kitchen tap to help remove sodium (e.g. reverse osmosis units). Boiling water does not remove sodium and will only increase concentrations.
