Sodium and potassium both are essential nutrients and The Food and Nutrition Board of
the National Research Council of America recommends that sodium intake be limited to no
more than 2400 mg per day (Beers & Berkow 1997). The Committee on Dietary Allowances
recommends 1875 – 5625 mg per day of potassium in order to maintain adequate and safe
levels of potassium balance (McCarron).
Sodium in drinking water is not a health concern for most people because in healthy people,
excess sodium is eliminated through the kidneys and the correct balance of sodium and water
is maintained. But for people with heart disease, hypertension, kidney disease and circulatory
illness or on a sodium-controlled diet, it may be an issue of health concern because of their
inability to maintain the required body balance of sodium (Beers & Berkow 1997). The WHO
and USEPA have restricted people with hypertension or those on sodium-restricted diet to
drink water with sodium content not more than 20 mg/l. Those on moderately restricted diet
should not drink water containing more than 270 mg/l of sodium (Canadian Water Quality
Guidelines 1987).