Sodium in well water: when it matters
Sodium isn't a concern for most people. Above 20 mg/L, anyone on a sodium restricted diet should tell their doctor. Water softeners add sodium.
- US (EPA)
- No enforceable limit; EPA advises 20 mg/L for people on very low sodium diets.
- Ontario
- Aesthetic objective 200 mg/L; the medical officer of health is notified above 20 mg/L.
What it is
Sodium comes from natural minerals, road salt and water softeners. Drinking water is usually a small part of total sodium intake, but it can matter on a strict diet.
What your number means
- Within limitsBelow 20 mg/L
Low.
- Worth a look20 to 200 mg/L
Tell your doctor if anyone is on a sodium restricted diet.
- Worth a lookAbove 200 mg/L
Can taste salty. Look for the source.
What to do
- If anyone is on a low sodium diet, share the result with their doctor.
- Keep one unsoftened tap for drinking and cooking.
- If the level is rising, check for road salt or softener discharge near the well.
How often to test
With a full panel every 3 to 5 years.
Common questions
Does a water softener add sodium?
Yes. Salt based softeners swap hardness for sodium, more for harder water.
Can road salt get into my well?
Yes, especially for wells near roads or driveways that are salted in winter.
Sources: EPA secondary standards; Ontario: testing and treating private wells. Limits checked October 2026.