1938 Congress authorizes funds for the planning of a dam and reservoir on the upper Salt River basin for flood control of the upper Mississippi River Basin.

1962 The Flood Control Act authorizes construction of the Joanna Dam (renamed Clarence Cannon Dam in 1972) and reservoir. The plan officially becomes a multipurpose project to provide flood control, hydroelectric power generation, water supply, recreation and fish and wildlife conservation. 

1982 Steering committee is formed to address the water supply needs of Northeast Missouri. 

1983 CCWWC organized as a Joint Municipal Utility Commission with twelve participating cities and rural water districts. Mark Twain Lake construction is completed and the sluices are closed in August to begin filling the new reservoir.

1989 Bond elections held in twelve municipalities and rural water districts. The $25 million bond was approved by voters with an overall approval of 93%.

1991 Construction begins on a 4.5 MGD water treatment facility, transmission lines, storage tanks and pumping stations.

1992 Completion of the CCWWC system construction. First water sales to member systems occurred June 16, 1992. 

1994 The first extension to the system is completed providing water to the City of Vandalia to serve the Women’s Eastern Reception Diagnostic and Correctional Center. 

1997 Revenue bond issue approved by voters in Pike County PWSD#1 to extend the transmission system to Pike County. 

2000 Revenue bond issue approved by voters in Edina, Lewistown, LaBelle and the Lewis County PWSD #1 to extend the transmission system to these entities. The existing treatment plant capacity is expanded to a total of 5 MGD.

2005 Design work begins on a new 5 MGD water treatment plant to be constructed beside the existing treatment plant. Transmission system expansion plans are under way to serve the Macon PWSD #1 and the city of Armstrong.

2007 The new treatment plant began production in July 2007. The combined treatment plants are now capable of producing 10 MGD per day. Macon PWSD #1 and the city of Armstrong begin to take water. Due to the previous two dry summers, the cities of Bowling Green and Wellsville approach the CCWWC with a request to purchase wholesale water. 

2011 A $10 million transmission system expansion is completed to add finished water storage for the eastern portion of the system and to serve Bowling Green and Wellsville.

2015 The city of Armstrong becomes a part of the Thomas Hill Public Water Supply District #1, reducing the CCWWC membership to 23 Cities and Public Water Supply Districts. (Our members in turn serve 4 secondary systems)

2019  An $800,000 construction project was completed on a 12 inch ductile iron pipe lake crossing on the North Fork arm of Mark Twain Lake near Hwy 107.  The project enhances service to Cannon Water Supply District and Marion County PWSD#1, while providing the ability to expand water flows to that quadrant of the CCWWC service area.