Sulfate in Drinking Water: Safe Limits & Health Effects
Naturally found in mineral springs
Optimal Min in Water
0
Optimal Max in Water
100
Unit
mg/L
Symbol
SO4
Who Limit
250
None
5 min read
Overview of Sulfate in Drinking Water
What it is: Sulfate (SO₄) is a naturally occurring compound of sulfur and oxygen. It's one of the major dissolved components in many groundwater sources and contributes to water's mineral character.
Why it matters: Sulfate affects water taste significantly—adding bitterness at higher concentrations. Combined with magnesium, it can have a laxative effect, which some mineral waters are specifically known for.
Natural sources: Dissolves from gypsum, anhydrite, and other sulfate-bearing minerals. Industrial discharge, mining runoff, and atmospheric deposition can elevate levels. Common in volcanic regions.
Optimal range (0–100 mg/L): Low to moderate sulfate provides mineral content without affecting taste. Water is suitable for all uses including infant formula preparation and brewing coffee or tea.
Too high (>250 mg/L): WHO guideline is 250 mg/L based on taste. Can cause noticeable bitterness and, combined with magnesium, may cause digestive effects. Some therapeutic waters intentionally exceed this.
Health note: Sulfate is not considered toxic, but high-sulfate water should be avoided for infants due to potential laxative effects. Adults may experience temporary digestive adjustment.
