Is tap water unhealthy?

Tap-water safety varies by location: some supplies contain contaminants of concern, so check your local water-quality report and consider filtering your water. 1 2

• Potential contaminants: Disinfection byproducts from water treatment and other contaminants may affect health; the episode specifically discusses endocrine disruption and effects on reproductive health. 3
• Filtering and letting water stand: Properly maintained carbon pitcher filters can reduce some disinfection byproducts, though the episode says they may not remove enough fluoride. Letting water sit uncapped may remove some contaminants, but it is described as less effective than filtration. 4 5
• Hard water: Magnesium- and calcium-rich “hard” water may have benefits. The episode describes an association between higher magnesium in drinking water and lower cardiovascular mortality, not proof that hard water prevents cardiovascular disease. 6