Sewage Lagoon, located in Sweetwater, Wyoming, is a privately owned water resource structure designed by George C. Toland in 1976. This Earth dam stands at a height of 12 feet with a hydraulic height of 9 feet, serving a primary purpose other than flood control. With a storage capacity of 148 acre-feet, this lagoon covers an area of 18 acres and has a low hazard potential as assessed in 2019.

Despite being state regulated and permitted by the Wyoming SEO, Sewage Lagoon has a fair condition assessment and a high risk assessment due to its location in a high-risk area. The structure lacks a spillway and outlet gates, with no associated locks or drainage area. The last inspection in 2019 revealed no major issues, but the risk management measures and emergency action plan status remain unclear. Sewage Lagoon presents a unique challenge for water resource and climate enthusiasts, highlighting the importance of infrastructure maintenance and risk mitigation in managing wastewater systems.