Douglas County approves Sedalia wastewater design and Shadow Mountain paving agreement
Commissioners approved a $375,232 design amendment for the next phase of the Highway 85/Sedalia wastewater project and an agreement coordinating a waterline replacement with full-road paving.
Douglas County commissioners approved a $375,232 design amendment Aug. 11 for the next phase of the Highway 85/Sedalia wastewater project and an agreement coordinating the Shadow Mountain waterline replacement with full-road paving.
The amendment funds design for about 3,000 linear feet of gravity sanitary sewer in Sedalia, from the north side of Highway 85 to a planned lift station. Commissioners approved it unanimously. The action authorizes design funding, not construction funding for that sewer phase, the amendment says.
The broader project is estimated at about $19 million. County staff told commissioners it is primarily funded with American Rescue Plan Act money. A 2024 county project update identified $14 million in ARPA funding for the southern Highway 85/Sedalia component. The available records do not provide a complete breakdown of the remaining roughly $5 million. Staff said future construction funding is also anticipated from congressionally directed spending and contributions from Castle Rock and Douglas County.
The project’s initial lift station and force main are under construction, with wastewater planned to flow from Sedalia to Castle Rock’s Plum Creek Water Reclamation Facility. The extension is intended to serve some Sedalia residences, the CORE headquarters and the county’s future GreenWorks facility. The records do not establish completion dates, a phase-by-phase construction schedule or when customers will receive service.
Commissioners also approved an intergovernmental agreement with the Highlands Ranch Water and Sanitation District covering roughly 1,300 feet of waterline work. The agreement coordinates the project with county-managed final paving and anticipates construction beginning by Nov. 1, 2026, with paving substantially complete by Nov. 30, unless the parties agree otherwise.
The county will pave the full roadway rather than mill and overlay only the half containing the waterline trench. The agreement estimates the paving improvements at $106,000 and caps the water district’s contribution at $44,000. The records do not identify a road closure, detour, other specific traffic restriction or water-service activation date.