I’m intruding on David Zetland’s turf, but in this 2012 Guardian article from 2012 Roger Cowe makes some compelling arguments about why agricultural water subsidies lead to perverse outcomes, do not help the poor, and waste a precious, scarce resource. Water is the only industry in which regulation more perversely stifles self-organizing processes for managing scarcity than electricity. His conclusion is apt:
Like most other perverse subsidies, the goal of improving access to water is not at issue. The perversity arises because making water cheap, especially to crop farmers, leads to excessive use and unintended, environmentally harmful consequences. And the poor, who are often the main targets of subsidies, typically don’t benefit. Irrigation benefits landowners rather than their tenant farmers. And surprisingly, consumption subsidies do few favours for poorer families.