Local Water Quality, Diarrheal Disease, and the Unintended Consequences of Soda Taxes

Abstract

Abstract Could taxing sugar-sweetened beverages in areas where clean water is unavailable lead to increases in diarrheal disease? An excise tax introduced in Mexico in 2014 led to a significant 6.6 percent increase in gastrointestinal disease rates in areas lacking safe drinking water throughout the first year of the tax, with evidence of a diminishing impact in the second year. Suggestive evidence of a differential increase in the consumption of bottled water by households without access to safe water two years post-tax provides a potential explanation for this declining pattern. The costs implied by these results are small, particularly compared to tax revenues and the potential public health benefits. However, these findings inform the need for accompanying soda taxes with policy interventions that guarantee safe drinking water for vulnerable populations.