State Departments of Transportation Practices for Outsourcing Inspection and Maintenance Activities of Post-Construction Stormwater Best Management Practices Assets

Post-construction stormwater best management practices (BMPs) are engineered facilities designed to treat stormwater runoff from developed sites, such as buildings, roads, and parking lots. These BMPs aim to reduce stormwater runoff, prevent erosion, and improve water quality by removing pollutants. Because of limited maintenance staff, state departments of transportation (DOTs) often outsource the inspection and maintenance of these BMPs to third-party contractors to maintain functionality and performance. The study aimed to identify the motivations behind state DOT stormwater programs, the extent to which DOTs outsource these activities, the reasons for outsourcing, the types of contracts used, funding sources, standards for contractor performance, and how contract costs are determined. The research employed a four-step methodology that included a literature review, a web-based survey, data sorting and analysis, and semi-structured virtual interviews. The study revealed that many state DOTs have in-house procedures and manuals for post-construction BMP inspection and maintenance. Of the 41 DOT responses, 35 DOTs own or manage BMPs, and 19 of these outsource inspection and/or maintenance activities. Compliance with National Pollutant Discharge Elimination System Municipal Separate Stormwater System Phase II permits for urbanized areas is the primary driver for DOT stormwater programs. The main reason for outsourcing is staffing shortages. Inspection services are often qualification based, whereas maintenance services are selected through open bidding. Funding for inspections typically comes from statewide capital or operating budgets, whereas maintenance funding comes from district or regional budgets. Contractor performance is primarily assessed through informal oversight for inspections and by evaluating work completed for maintenance.