<p><em>Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Several epidemiological studies have shown that areas with harder water have a lower incidence of CVD, indicating that magnesium may be the cardiovascular-protective factor. Magnesium is required for various biochemical reactions and is a structural component of cardiac muscle. The overreliance on processed foods, lack of green leafy vegetables, and softened drinking water can contribute to magnesium deficiency. Magnesium supplementation through fortified drinking water can result in public health interventions to prevent many diseases, particularly CVD. This review provides an overview of the role of magnesium in preventing atherogenesis, endothelial damage, inflammation, and dyslipidemia, all of which are the central factors for CVD development. The review also focuses on the appropriate amount of hardness and total dissolved solids in drinking water for optimal conditioning to reduce the amount of CVD mortality. This study concludes that appropriate and timely therapies involving adequate magnesium intake through drinking water could avert morbidities and mortalities due to ischemic heart diseases and other cardiac problems caused by magnesium deficiency. In summary, the study provides strong evidence of the inverse relationship between water hardness and CVD, and the potential for magnesium supplementation in drinking water to reduce CVD mortality by up to 15% in the US.</em></p>