Silver in well water: the 0.1 mg/L guideline
The EPA cosmetic guideline for silver is 0.1 mg/L. Ontario has no standard. Silver is rare in wells, and most results come back below detection.
- US (EPA)
- 0.1 mg/L cosmetic guideline.
- Ontario
- No standard.
What it is
Silver is rare in groundwater. It can come from mining areas or from water filters that use silver to control bacteria.
What your number means
- Within limitsBelow 0.1 mg/L
No effect expected.
- Worth a lookAbove 0.1 mg/L
Over many years, high silver can cause a blue gray skin discoloration called argyria. Find the source.
What to do
- If you use a filter that contains silver, ask the maker about how much it releases.
- Retest a sample taken before any filter.
- Reverse osmosis removes silver.
How often to test
With a full panel every 3 to 5 years.
Common questions
Why would silver be in my water?
Usually from a filter that uses silver to stop bacteria growth, or rarely from mining areas.
Is silver a health risk?
Only at high levels over many years, when it can discolor the skin. It is a cosmetic guideline, not a health limit.
Sources: EPA secondary standards. Limits checked November 2026.