The wettest country in the world is Columbia, which receives over 3200 ml of rain annually and the driest nation, Egypt, receives just 18 ml. Agriculture uses around 70% of the world's freshwater, and irrigated farmland is crucial in delivering, on average, double the production of rainfed farming and 40% of the world’s total food production. Jane Craigie discovers how farmers, policymakers and land investors navigate water availability and rights, and how technology helps preserve every precious drop in times of shortage, while too much rain grinds everyday farming to a halt.