Water scarcity is a growing challenge to the governance of water resources and to multiple water uses. Dealing with water scarcity requires a better-shared understanding of water supply and demand dynamics on the part of the different stakeholders who contribute to and/or suffer the consequences of water scarcity. This study highlights the importance of establishing a water accounting system for groundwater management in the Berrechid plain (Morocco) and the conditions under which such accounting may help solve current water issues. The plain is under considerable water stress, and stakeholders are struggling to implement aquifer management plans to ensure groundwater sustainability. The study identified and quantified various components of the water balance and estimated annual groundwater overexploitation for the period 2001–2018 to be 32 million m3. Fractional analysis of the water balance showed that the reason for aquifer water stress was a rapid increase in irrigated land and current intensive agricultural and irrigation practices, which threaten both the sustainability of water resources and economic activities in the plain. To improve water governance, a system of water accounting is required that promotes responsible use and ensures that all stakeholders are answerable and accountable for their water consumption along with any actions that may affect water flows.