By Siti Maimunah and Sarah Agustiorini Increasing pressures from extractive industries on the Mahakam River in Kalimantan, the second largest river in Indonesia, risk an irreparable destruction of a commons. Yet residents are actively organizing to reclaim the river as a common living space, as Siti Maimunah and Sarah Agustiorini illustrate in this new post of the series “Reimagining, remembering, and reclaiming water: from extractivism to commoning”.