This guide provides Inspectors with guidelines for routine condition assessment of culverts or storm drains, and includes a reliable and reproducible method to rate the condition of all system components. This component-based rating system enables qualified inspectors to assess common distress types, evaluate their severity, understand their significance, and assign a numerical condition rating that is associated with recommendations for further action, if necessary.

The guide has been developed as a resource to agencies developing and conducting culvert and storm drain inspection programs, as well as developing transportation asset management plans for culvert and storm drain system inventories. It includes current information based on best practices in the area of culvert and storm drain system inspection, which agencies may use as a reference on which to build inspection, assessment, and management criteria best suited to their particular agency's needs.