The historic rainfall dumped by Hurricane Harvey has already led to deaths by drownings and the destruction of many homes. Houston’s drinking water system is being stressed by overflowing water reservoirs and dams, breached levees and possible problems at treatment plants and in the water distribution system. Failure of drinking water systems could lead to water shortages...  I also see a number of public health concerns. Raw sewage, dead bodies in the water and release of dangerous chemicals into the floodwaters could lead to the spread of disease through contact with contaminated water and to infection through open wounds... Because Houston has at least a dozen sites that have been designated environmentally hazardous, there is a risk of petrochemical contamination. Indeed, companies have reported that pollutants from refineries have already been released... [Also] the “unprecedented” amount of water leads to the perfect breeding opportunities for mosquitoes, which are vectors of Zika and many other infectious diseases... Flood impacts hit hardest on the most vulnerable and exposed people, especially children, the elderly and disabled, and the poor...