In 1945, Johnson County, Kansas, negotiated with the City of Kansas City, Missouri to treat wastewater from the County.  An agreement was not achieved and Johnson County's Commissioners created the first JoCo Sewer District and sewer system to serve one of the fastest growing counties in the country.  Construction of the first treatment plant began two years later before the Board hired a single District employee.     

Johnson County Chief Engineer Myron K. Nelson was hired to guide the growth of the wastewater collections and treatment systems.  Myron and his staff laid the foundations for the physical buildings, treatment units, sewer system and the philosophies for quality and purpose.  

The first treatment plant, Mission Township No. 1 Treatment Plant, began operation in 1949 to serve a population of 15,000.  Keeping up with the demand for sewers for subdivision after subdivision in JoCo was difficult in the 40s and 50s with the construction shortages of the day.  But, four years after completion, the Mission Township Plant was upgraded to double its treatment capacity and, soon after, construction began on the second JoCo treatment plant. 

JCW continued to meet growth challenges.   

That single treatment plant in 1949 has grown to six major treatment plants and the one employee hired in 1947 has grown to over 200 employees.  

The 1995 completion of the Mill Creek Regional Wastewater Treatment Plant proved to be a Johnson County environmental and economic success by providing vital sewer capacity for the fast growing cities of Shawnee, Lenexa, and areas of Olathe.  

The Tomahawk Creek Wastewater Treatment Facility was originally constructed in 1955 and expanded over the years to treat wastewater flows from parts of Leawood, Overland Park, Olathe and Prairie Village. With continued population growth, the facility was eventually unable to treat all of the flow and approximately 60% was sent to Kansas City Missouri for treatment.  Johnson County Wastewater began reconstruction of the Tomahawk Facility in April 2018 to improve assets, increase treatment capacity and address challenges such as: aging infrastructure, high Kansas City Missouri rate increases, and stricter limits from the Environmental Protection Agency and Kansas Department of Health and Environment for discharges of ammonia, nitrogen and phosphorus.  The Facility started accepting flows September 4, 2021.  Six weeks ahead of schedule. 

And growth continues.  

Large scale improvements to the Nelson Complex, which includes that first treatment plant (Mission Township No. 1), are currently in the planning stages.        

Investing in JCW facility improvements helps preserve the high quality of life enjoyed by Johnson County residents by: 

• Protecting the environment and improving water quality in receiving creeks\streams and for downstream communities; 
• Improving treatment operations by applying the latest technologies; and 
• Providing the most cost-effective, long-term solutions for customers.  The Tomahawk Facility alone will save approximately $16 million annually.