Sodium in Well Water: Is It Harmful? (Answer: Not Really)

According to the World Health Organization, “the sodium ion is ubiquitous in water.”[1] Sodium is on the EPA’s Contaminate Candidate List, a list of contaminants that are known to occur in public water systems and may require regulations under the Safe Drinking Water Act, but are not currently subject to “any proposed or promulgated national primary drinking regulation.”[2]

This is because sodium is a necessary part of the human diet and basically harmless in drinking water. It has been linked to hypertension in some individuals, but is “unlikely to be a significant contribution to adverse health effects” for most.  In fact, the EPA recommends a sodium level of 20 mg/L in drinking water just to meet basic nutritional needs. The same report lists sodium’s “taste threshold” as ranging from 30-60 mg/L. Note, however, that “EPA believes this guidance level for sodium needs updating, and is probably low.”

EPA estimates that an average adult (weighing 150 lbs) who drinks 2 liters (8 glasses) of water a day will ingest less than 100 mg of sodium a day, far short of the overall recommended daily sodium intake of 500 mg. By these calculations, there is not much to worry about from sodium in your water, unless your sodium concentration is abnormally high.

Clean Water Test Kit Well Water sodium

Clean Water Test Kit

The best way of finding your sodium concentration is to send a sample of your water to a lab for total dissolved solid testing (covered yesterday) which will give you individual readings of the various contaminants considered TDS, of which sodium is one. Both our Well Test Pro kits I and II come with a prepaid mailer for sending us your sample; you could also use a Clean Water test kit or a Watercheck test kit to test for sodium yourself.

You can treat sodium the same way you would treat TDS as described in yesterday’s blog post: with a reverse osmosis filter, ideally preceded by an anti-scalant injection to preserve the system and keep your water salt-free for many years.

About the Author Gerry Bulfin

Need help with your well water? I have been assisting homeowners, small communities and businesses improve their well water quality since 1989. Please email me at if you have a question about water testing, test kits or well water systems in general. Gerry Bulfin CWS-IV Master Water Specialist WQA Certified Licensed California Water Treatment Contractor