Aquifer overexploitation is widely used to describe negative effects on groundwater resources but has no agreed scientific definition. Usually viewed as a situation where average aquifer abstraction exceeds average recharge, a diagnosis of groundwater overdraft calls upon specific hydrogeological instruments, based on the groundwater balance approach. An analytical method for assessing changes in water flows and stocks through time and space, groundwater balance is also a tool for the investigation of knowledge construction and its embeddedness within power relations. We propose to discuss the politics of groundwater overexploitation diagnoses in Syria and more specifically the Orontes River Basin prior to the 2011 uprising and subsequent conflict. Groundwater overdraft at the national level became a matter of concern in official discourse in the late 1990s as diagnoses of groundwater overexploitation became commonplace in international reports. The steady increase in groundwater abstraction in relation to Syria's centralised agricultural planning from the 1960s onward had undeniable consequences on the hydro-social system. However, the way diagnoses of groundwater overexploitation – in particular groundwater balances – were constructed and used to support water policies implemented from the mid-1990s onwards question the rationalities and interests lying behind technical arguments and actions.