Sodium in Drinking Water 

Important Information for Residents on Sodium-Restricted Diets

Health Canada’s aesthetic guideline for sodium in drinking water is 200mg/L. Above this concentration, water is unpleasantly salty. As required in the Ontario Drinking Water Systems Regulation 170/03 under the Safe Drinking Water Act, the City of Brantford notifies the local Medical Officer of Health when the sodium concentration is 20mg/L or greater. This is so that physicians may provide further support to their patients who have been medically advised to follow sodium–restricted diets. For healthy individuals, sodium in water at this concentration is not a health concern.

The sodium concentration in drinking water reflects the level found in the Grand River and it is not removed by conventional water treatment processes.  In 2017, the sodium in Brantford’s drinking water supply had an average concentration of 43 mg/L ranging from a minimum of 33 mg/L to a maximum of 64 mg/L. Sources of sodium in the Grand River may be from geological salts that are naturally washed out of rocks and soils as well as what is contributed from road salt and discharges from water softeners.  If you use a water softener in your home, please note that it will increase the sodium level in the drinking water and would contribute to a person’s daily sodium intake. Overall, sodium from municipally supplied drinking water is responsible for a very small fraction of the total sodium consumed daily.

For additional information on health impacts from sodium in drinking water please contact the Brant County Health Unit at 519-753-4937, ext. 470

Sodium In Drinking Water Factsheet: What you need to know about sodium in drinking water.

What is sodium?

Sodium is a mineral commonly found in food and water. Your body needs sodium daily to regulate fluids, maintain blood pressure, and for muscle and nerve functions.  Since it is an essential nutrient, there is only an aesthetic guideline for the amount in water as established in the Guidelines for Canadian Drinking Water Quality and Ontario Drinking Water Standards. This means that above the guideline of 200mg/L, water has a noticeably salty taste but is not harmful to healthy people. Sodium in water is only a concern to those who have hypertension and/or heart-disease and who are on sodium-reduced diets.

How does sodium get into water?

There are numerous sources of sodium in water. As it is a mineral, sodium naturally occurs and is quite prevalent in groundwater. Road salts will contribute to increased sodium levels, especially seasonally as snowmelt and runoff occurs. Water softeners remove hardness but in the process elevate sodium levels in water. In Brantford, sodium in water is from a combination of natural minerals and road salt.

What is the sodium concentration in Brantford water versus the Guidelines for Canadian Drinking Water Quality?

The Guidelines for Canadian Drinking Water Quality have an aesthetic guideline for sodium of 200mg/L. Above this concentration, water noticeably tastes salty. However, this amount could make water a significant source of sodium for those with hypertension and heart disease. For this reason, it is required by the Ontario Drinking Water Systems Regulation 170/03 under the Safe Drinking Water Act to notify the local Medical Officer of Health when sodium levels are above 20mg/L. Through this notification, it is strongly recommended that those with sodium-reduced diets consult with their physicians about their sodium intake. In 2015, the average sodium level in Brantford's drinking water supply was 62 mg/L. This is still well below the aesthetic guideline and is not a factor for healthy individuals, but is an issue to consider for the very small group of Brantford residents who are on severely sodium-restricted diets.

How will I know if sodium levels are greater than 20mg/L?

If the sodium concentration in the water is above 20mg/L, the Medical Officer of Health (MOH) will be notified. The MOH may choose to inform local physicians. Alternatively, the City of Brantford will release a notification directly to city residents through advertisements such as brochures in the hydrobill, website, etc.

What is a normal daily intake of sodium and how much is contributed by Brantford drinking water?

Sodium is an essential nutrient required for physiological functions, but often more sodium is consumed than the body requires. According to Health Canada, the maximum recommended daily intake for an adult is 2300mg. Using Brantford's 2015 average sodium concentration, 2 L of water has 124 mg. This represents approximately 5% of the maximum recommended daily sodium.

The most prevalent source of daily sodium originates from food. 77% of sodium is from processed foods, 12% is naturally in foods, 6% is added at the table for seasoning and taste, and the remaining 5% is added during cooking. For a healthy adult, the amount of sodium contributed through drinking water is very small. It may only be a significant source for those on sodium-restricted diets. On a diet of only 500mg per day, 2 L of water can contribute 23% of daily sodium. It is important for those on sodium restricted diets to be aware of sodium sources, to track their intake and to consult with their physicians regarding further sodium-reducing steps

Examples of common sodium levels in food and beverages:

  • 1 cup of a cream-based soup - 1080mg
  • 1 3cm cube (30g) of cheddar cheese - 210mg
  • 1 slice (37g) of white bread - 195mg
  • 1 apple (approx. 125g) – 1mg
  • 1 can (368g) of a carbonated cola beverage – 15mg
  • 100g of regular potato chips – 525mg