California is one of the most economically vital, socially vibrant, and ecologically diverse regions in the world, and all this is dependent on water. Yet, the long-term security of its water supplies is at risk. California has reached, and in many cases exceeded, the physical, economic, ecological, and social limits of traditional water supply options. Under business-as-usual conditions, California faces a 10 percent water supply gap by 2040. The economic cost of this water scarcity is estimated to be over $5 billion per year. Because of the confluence of economic importance and water stress, California has emerged as a proving ground for corporate water stewardship practices that go beyond their own operations to help address shared water challenges. This paper sets out to capture the trajectory of corporate water stewardship, both as a global movement and as on-the-ground action in California.

1. Water challenges present a material business risk, and it cannot be managed through individual action. California’s experience shows that even best-in-class operational water management cannot fully protect companies from water risks at the basin scale. Effective risk mitigation requires engagement beyond facilities through collaboration with other water users, communities, and public agencies.
2. Volumetric water targets have mobilized action, but they are no longer sufficient on their own. Time-bound, volume-based targets have helped accelerate corporate investment and accountability, yet an overreliance on “cost-per-drop” metrics can discourage investments in projects that deliver critical long-term, social, ecological, or policy-enabling benefits.
3. Collective action delivers scale, credibility, and measurable outcomes. California demonstrates that structured, third-party-facilitated collaboratives enable companies to move faster, de-risk investments, and achieve outcomes that no single company could deliver alone.
4. Aligning corporate water action with public policy unlocks outsized impact. The greatest opportunities for durable water resilience emerge when corporate investments complement public policy priorities.
5. The next phase of corporate water stewardship is about leadership. Closing California’s projected water supply gap, and managing escalating climate-driven water risks, will require many more companies to engage and existing leaders to go further by investing in innovation, early-stage project development, financing mechanisms, and public-private partnerships.