Sodium in Drinking Water

Sodium is a naturally occurring mineral that is commonly found in drinking water.

Should I be concerned about sodium in my drinking water?

Food products, not water, account for most Canadians’ sodium intake. The human body needs sodium in order to maintain a normal fluid balance.¹ Healthy adults need only 1500 mg of sodium per day and healthy children need only 1000 to 1500 mg of sodium per day.¹ However, most of us eat about 3400 mg of sodium per day.¹ View Cut out the Salt to see which foods are high in sodium and tips for lowering your sodium intake.

How much sodium is allowed in drinking water?

The Guidelines for Canadian Drinking Water Quality² set an aesthetic objective for sodium in drinking water of ≤200 mg/L, at which point it can be detected by a salty taste. A maximum acceptable concentration for sodium in drinking water has not been specified.

Under Ontario's Drinking Water Systems Regulation (O. Reg. 170/03), it is required that a report be made to the local Medical Officer of Health if a water system’s sodium level exceeds 20 mg/L.³ The Medical Officer of Health must then inform physicians and other health care professionals to inform people following sodium restricted diets about this issue so they can adjust their sodium intake, if needed.

How much sodium do people usually get from drinking water?

In the case of a water system with drinking water having a sodium concentration of 20 mg/L, drinking 2 litres per day would contribute 40 mg of sodium to a person’s diet. For healthy adults, this level of sodium in drinking water does not pose a risk. For individuals on very strict sodium restrictions of 500 mg per day, two litres of water with a concentration of 20 mg/L would contribute around 8% of their daily sodium allowance.

In addition, people using a water softening system in their home may have higher levels of sodium in their drinking water as most softeners use a calcium-sodium exchange system. This may add significant amounts of sodium to drinking water in the home. There are numerous treatment units that may aid in the removal of sodium from softened water, including reverse osmosis, ion exchange, or distillation units. Alternatively, a separate water line which bypasses the water softener may be used to provide drinking water.

Additional Information

To speak to a Public Health Inspector on the Environmental Health Team about sodium in drinking water, please call:

• 519-663-5317

Visit the Health Unit's web page on sodium for more information on sodium and healthy eating.

To speak to a Registered Dietitian about sodium and healthy eating, please call Telehealth Ontario:

• 1-866-797-0000