Cape Town, South Africa, has designated July 9 “Day Zero.” That’s when water taps throughout the city are expected to go dry, marking the culmination of a three-year drought. South African officials aren’t responsible for the lack of rain, but inept management and a devotion to anti-Israel ideology needlessly made the situation worse.

Even before Israel declared statehood in 1948, its leaders focused on water security as closely as they did military preparedness. Mostly desert, Israel would need adequate water to thrive. In...