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Facts About...


What is sodium?

Sodium is an essential mineral for humans. We all need a small amount of sodium to keep our bodies working properly. Sodium helps us maintain blood pressure, control fluid levels, as well as keep normal nerve and muscle function. According to the Canadian Community Health Survey, in 2004, each Canadian consumed approximately 3 grams (3000 mg) of sodium every day.

Where does sodium come from?

Sodium is found in most foods, soft water, some mineral waters and drugs such as antacids, laxatives, aspirin, and cough medicines. Sodium can also be found in drinking water supplies. The most common sources of sodium in drinking water are from natural occurrences, road salt, water treatment chemicals and ion-exchange water softening units.

How much sodium is acceptable in drinking water?

All natural waters contain some sodium. In Ontario, the Drinking Water Systems Regulation (Reg. 170/03) and the Small Drinking Water Systems Regulation (Reg. 319/08) require owners/operators to report to the local Medical Officer of Health (MOH) when sodium levels in public drinking water supplies exceed 20 mg/L.

How will I know if the levels exceed 20 mg/L?

Once notified, the MOH may inform local physicians. The MOH may also require the owner/operator of the drinking water system to advise the users of the water.

Who should be concerned about sodium in drinking water?

Sodium in drinking water is not a health concern for most people, but may be an issue for someone suffering from hypertension (high blood pressure), congestive heart failure, or any other medical conditions requiring a low sodium diet.

If the sodium concentration in your drinking water is 20 mg/L, drinking up to 2 litres of water per day will add 40 mg of sodium to your diet, about 2% of a teaspoon of salt. For healthy adults, this sodium level in drinking water does not pose a risk. Even for individuals on sodium-restricted diets of 500 mg of sodium per day, 2 litres of water would only account for 8% of their daily allotment of sodium.

What should I do about the sodium in drinking water?

Most people don’t need to take any action. If you are on a sodium-restricted diet, experiencing severe hypertension, or congestive heart failure, you should consult your physician about the concentration of sodium in your drinking water. Your doctor may recommend that you drink sodium-free bottled water.

More information can be obtained from

Durham Region Health Department, Environmental Health Line, 905-723-3818 or 1-888-777-9613

April 22, 2013

For more information call
905-668-7711 OR 1-800-841-2729