Before committing substantial resources toward addressing water challenges, it is important for a company or community to understand how much water stewardship activity and investment is likely to be required to measurably reduce water stress. In short, how much improvement is enough? Given that many parties will be contributing to a water stewardship collective action, this question will usually need to be answered through a dialogue among the local water community. The community should strive for general agreement about “optimal” water conditions and use, which will likely invoke conversations about the needs and desires of different users or user groups, as well as what “sustainability,” “water security,” or sufficiency might mean for water management as a whole. This dialogue should address the issue of how much and what quality of water must remain in the water source to protect freshwater ecosystems, cultural values, or provide a hedge against dry periods. It should also build on previous hydrologic assessments, environmental flow determinations, or basin plans that have been developed previously. The Guide to Water-Related Collective Action provides very useful guidance about the processes that can be employed to build consensus among actors within a water community. The sufficiency gap can be determined as the difference between what exists and what the water community collectively needs or wants (see Figures 2 and 5). This difference or gap represents the extent of insufficient conditions. Understanding the extent and nature of the gap can help orient water stewardship collective actions. Sufficiency is achieved when this gap is closed. This concept can be applied to various parameters and conditions that cause water stress, including water balance or water scarcity, but also water quality and access to water and sanitation services. To the extent possible, the agreed-upon desired conditions, or the determination of what would constitute sufficiency of stewardship action, should be quantified so that progress toward those desired conditions can be most easily measured and communicated. Figure 5 A central challenge of managing water sustainably is gaining community consensus around the water-related values and benefits to be gained by using water, or by leaving some portion of available water supplies for ecosystem support. This graph illustrates a fictitious scenario in which the community has decided to reduce its overall consumption of water, perhaps to sustain a fishery. The upper graph represents current conditions. In the bottom graph, the volume of water savings (reduced consumption) targeted for each month to attain the desired condition is represented by the green portion of the bars. Once this volume of savings is achieved, the community’s water stewardship activities will be “sufficient” to meet its collective ecosystem-restoration-related goals for water management.