A drastic new message adorns the walls of the Iranian capital, usually reserved for war heroes and weapons.

“There is a water shortage!” reads the government poster slogan, inside a water container that is nearly empty. “It’s fall and there is still no rain.”

That’s not news to Erfan Ensani, 39, who returned home from a long day working in the textile section of the city’s central bazaar last week to find his taps running dry.

Iran is facing its worst water crisis in decades. With no end in sight and authorities warning they may even have to evacuate the capital of 10 million people, residents like Ensani are scrambling to respond.