Sulfate
Cities measured
87
Detected in
87 / 87
EU limit
250 mg/L
Highest
168 mg/L — Abu Dhabi
Overview
Sulfate enters water through dissolution of gypsum and sulfate minerals, atmospheric deposition (acid rain), and industrial discharge. It is a major anion in most drinking waters. Stockholm's low-mineral granite-source water has relatively low sulfate.
Health Relevance
High sulfate (> 500 mg/L) can cause osmotic diarrhoea in sensitive individuals — particularly infants and newcomers. Below 250 mg/L, no adverse health effects are established.
Regulatory Limits
Drinking Water Directive 2020/2184
250 mg/L (indicator — taste threshold).
Controversy & Contested Science
Sulfate-reducing bacteria (SRB) in hot water systems and distribution pipes can produce hydrogen sulfide (H₂S) — causing 'rotten egg' odour and corroding copper pipes. Some utilities switched to chloramine disinfection (which penetrates biofilms better than chlorine) but chloramines react with rubber gaskets in household plumbing and degrade pipe fittings. The chemical balancing act in distribution system disinfection involves multiple interacting trade-offs that building owners and plumbers rarely understand.