The Sunizona community, in the south-western US state of Arizona, is just a speck on the map. A few hundred homes dot the landscape along dirt roads and for a few miles along a state highway that leads to the foot of the Chiricahua mountains near the New Mexico border.

Cynthia Beltran moved to Sunizona with her seven-year-old son last autumn even though the area lacks functional drinking water wells, because it was all she could afford. She cannot afford the $15,000 (£10,000) cost of deepening her well, which dried up last year, and had been paying for a local firm to deliver water in a tanker. But at $100 a week it became too expensive, so now she will be relying on a friend to help her fetch water from her mother’s well.