Hydropower activities must increasingly be evaluated from a sustainable development perspective. Corporate social responsibility (CSR) is the principle frequently applied to evaluate corporate contributions in this regard, though there exists no conceptual and theoretical basis that is common to the various approaches. With the present work, we fill this gap and provide a generic model that formally integrates the corporate and societal perspectives of hydropower activities within a welfare-economic framework that encompasses both externalities and distributional concerns. Building on this background and focusing on the current situation in Switzerland, the water tower of Western Europe, we particularly address the issues of water rights, resource rents and governance. This is crucial when analyzing investment projects of hydropower companies with shared private and public ownership; i.e., if external stakeholders are also sensitive shareholders who grant, at the same time, the company the right to operate. Altogether, this contribution shall support better informed decision making on both corporate and policy levels, especially regarding new and retrofitting investments in hydropower when social concerns are at stake.