Sodium
Cities measured
87
Detected in
87 / 87
EU limit
200 mg/L
Highest
188 mg/L — Abu Dhabi
Overview
Sodium regulates fluid balance and nerve function. In water it comes from geological sources, road salt runoff, water softening (ion-exchange), and sewage effluent. Stockholm's granite-bedrock water has naturally low sodium.
Health Relevance
High sodium intake is a well-established risk factor for hypertension and cardiovascular disease. At typical tap water concentrations (< 200 mg/L), drinking water contributes minimally to total sodium intake — food provides > 90% of dietary sodium.
Regulatory Limits
Drinking Water Directive 2020/2184
200 mg/L (indicator parameter).
Controversy & Contested Science
Ion-exchange water softeners replace Ca²⁺/Mg²⁺ with Na⁺, potentially raising sodium to 200 mg/L in softened water. A household drinking 2L/day could consume 400 mg extra sodium daily — ~17% of WHO's maximum intake recommendation. Cardiologists and dieticians have raised this concern; softener manufacturers counter that most users bypass the softener for their drinking tap. The asymmetry — softened water saves appliances but harms cardiovascular health — is a genuine regulatory gap in several EU countries.