The Central Puget Sound Regional Water Supply Forum represents Seattle, Tacoma, Everett, and Cascade Water Alliance, plus smaller entities like the Pierce Water Cooperative, East King (County) Regional Water Association, Woodinville Water and Sewer District and the Snohomish County Public Utility District. ) In an unprecedented voluntary three county regional approach to resiliency and preparedness to ensure water supply for more than 2.3 million residents, thriving ports, and world-class medical facilities. These major utilities have come together without the impetus of crises or mandates to identify critical risks to water supply and determine resiliency and preparedness so they can provide water supply to keep this thriving region functioning following crises. The Forum, its leaders, and members identified threats to water supply reliability. And, in response, brought together technical staff from all members and across all areas of expertise to examine best practices and cutting-edge analyses to determine the impact of and mitigation needed in their areas of critical concern: earthquakes, water quality, droughts, and climate change and identify next steps for the region.