Water softeners and a low sodium diet

Manintaining a low-sodium diet is more difficult if you use some types of "softened water".

To understand the problem you need to know a little about how water softeners work. They usually contain a chamber filled with beads or a chemical matrix called zeolite. This is an ion-exchanger and acts by replacing the chemicals in the water that make it hard (calcium and magnesium) with another ion, usually sodium. When the beads are "full" of calcium and magnesium, they are regnerated by passing a high level of sodium chloride through the exchanger, which displaces the calcium and magnesium and replaces it with sodium. Now, when the beads are exposed to hard water again, they continue to do their job of swapping calcium and magnesium for sodium.

For most individuals, the amount of sodium present in softened water is not a health problem. If however, you are trying to maintain a low sodium diet, this can add to your difficulties.

The amount of sodium in softened water can vary. According to a paper by Yarows et al., (Sodium concentration from water softeners, Arch Intern Med. 1997 Jan 27;157(2):218-22) the sodium concentration of softened well water averaged 278 mg/L but the variation was very large. Levels from 46 to 1219 mg/L were observed. 17% of households had sodium levels above 400 mg/L. The amount of sodium that gets added depends on how hard the water is to start with. If the water is very hard then the sodium level will be higher, as shown in the table below.

Initial Hardness
(Grains CaCO3/gallon)

Na added
mg/liter
10 75
20 150
30 225
The above figures are the amount that is in addition to the sodium content before the water is softened. If you are trying to limit your sodium intake to 1500 mg/day, then drinking 2 liters of water with 400 mg/L sodium over the course of a day will represent more than half your daily limit! In the same study, the mean sodium concentration of municipal, non-softened water was 110 mg/L (range 0 - 253 mg/L).

There are types of water softeners that do not add sodium to the water. Alternatively, if the ion-exchanger type of water softener is regenerated using potassium chloride, instead of sodium chloride, then potassium would be added to the water instead of sodium as the water was softened. However, in some patients with renal or cardiac disease, diabetes or high blood pressure, there can also be complications due to increased potassium intake so this should only be performed in consultation with your physician.

Finally, drinking LESS water is NOT a solution to this problem. In order to clear sodium from the body effectively, the kidneys need water. Higher rates of urine production allow greater amounts of sodium to be cleared, which is why diuretics are commonly prescribed to Meniere's patients. Ideally, you should follow the widely recommended guideline of drinking 8 glasses of water, each of 8 oz, per day.

Buying distilled water or using reverse-osmosis purification of your water for drinking may be an option.

I would be interested in hearing from patients who have previously dealt with this problem. I'm particularly interested in whether your symptoms changed after installing or removing a water softener and whether water softeners have any imapct on the management of Meniere's disease.