Metro Water Services (MWS) manages a complex sewer system that requires both proactive planning and rapid response to emerging conditions. Starting in 2018, they implemented an On-Call Investigative CM Services Program through the Clean Water Nashville Overflow Abatement Program (CWN). This Program connects real-time operational needs with long-term sewer system planning to support system reliability and inform capital decision-making. CWN utilizes a small, multidisciplinary team that is deployed to investigate sewer system concerns identified through customer complaints, flow monitoring data, and atypical conditions observed throughout the sanitary sewer system. The CWN Planning Group provides direction for investigations using flow monitoring to identify areas of concern, while MWS operations and maintenance staff provide input based on customer reports, pump station run-times and field experience. Local weather patterns often aid in identifying areas needing investigation. This field-driven approach allows MWS to quickly validate system performance, assess asset condition, and identify contributing factors that may not be evident through modeling or desktop review alone. On-Call Investigative CM Services focuses on sewer hydraulics, structural conditions, system connectivity, and 3rd party damages. Findings are documented and shared with MWS operations and planning staff in real time. A near-immediate data transfer allows for timely operational responses, while also supporting targeted maintenance activities. Just as importantly, the information collected in the field focuses longer-term capital planning and design decisions. Discoveries from the ’On-Call Investigative CM Services program have identified additional previously unplanned construction projects, and in some cases have shown that maintenance activities such as manhole lid replacement is more necessary than costly comprehensive basin rehabilitation. This has provided MWS the ability to administer ongoing manhole rehabilitation design and construction efforts system wide; as well as aided in concentrating sewer rehabilitation projects from broad areas within the MWS system. The CWN Planning Group also incorporates investigation results into broader system evaluations to help prioritize locations for future storage, rehab, or capacity improvements. Over time, On-Call Investigative CM Services has created a practical feedback loop between observed field conditions and planning assumptions. This presentation will describe how MWS’s On-Call Investigative CM Services Program model improves coordination between engineering, planning, operations, and maintenance; increases responsiveness to system concerns; and enhances overall understanding of the sanitary sewer system. The MWS ’On-Call Investigative CM Services Program demonstrates how a proactive, field-driven approach can add value to sewer system management while supporting resilience and informed infrastructure investment. Lessons learned, implementation considerations, and opportunities for applying this approach at other utilities will also be discussed. Collection systems cannot be kept in sound operational condition relying solely of capital projects. Rather, a programmatic system of investigation, documentation, and mitigation is fundamental to maintaining the system.