<p>Considering regional impacts on downstream communities and ecosystems is challenging in impact assessments. We suggest that environmental and cultural flows have the potential to be applied to protect water more comprehensively in assessment but are currently underutilized. Environmental and cultural flows refer to adequate water quantity and quality for the environment and Indigenous rights. Through interviews and a scoping review of legislation and assessments, we address how these concepts are and could be embedded within Canadian impact assessments. To date, environmental flows have been considered in assessments involving dams, oil and gas, and mining, and the focus has been on fish and habitat, rather than Indigenous rights and cumulative withdrawals. We propose Regional Readiness through water councils, change, and consensus (three Cs) to prepare watershed actors to protect environment and cultural flows in impact assessments. The three Cs are: (1) Advisory <i>councils</i> dedicated to creating regional objectives and rules for ecosystem and rights-based needs, (2) Assessing hydrologic and water quality <i>change</i> with regional data and relationships to water, and (3) Building <i>consensus</i> on the cultural and ecological significance and sensitivity of water bodies. Development of this framework follows examples from Canadian water-related assessments and initiatives: Wolastoq Ecological Limits of Hydrological Alteration, Athabasca Chipewyan and Mikisew Cree assessments, Yinka Dene Water Management Policy, Grand Council Treaty #3 Nibi Declaration, Slave Watershed Environmental Effects Program, and Strategic Assessment of Wood Buffalo National Park. These cases demonstrate how the inclusion of environmental and cultural flows processes in assessment could enable greater water protection.</p>