The everyday infrastructural practices devoted to making water flow and hedging the ever-present risk of breakdown give rise to whole landscapes of rumor, speculation, and stealth—on pipe locations, water pressures, and the timings and operations of valves, as well as on the networks of power and influence that underpin these volatile flows, appearances, and disappearances of water. Various kinds of knowledge about water are attained or hidden, leveraged or blocked through elaborate and power-laden activities of knowledge exchange. The opacities that infuse the distribution system animate constantly shifting sociopolitical and relational networks and fuel practices of knowledge brokering. Given the inexorable necessity of water, water knowledge is power. Controlling the dispersed networks by which that knowledge is accessed and mobilized becomes the stakes over which political players battle.