This guidance is intended to assist federal, state, regional, and local environmental professionals in tracking the implementation of best management practices (BMPs) used to control urban nonpoint source pollution. Information is provided on methods for inventorying BMPs, the design and execution of sampling programs, and the evaluation and presentation of results. The more regulated and stable nature of urban areas present opportunities for inventorying all BMPs versus the statistical sampling required to assess BMP implementation for agriculture or forestry. Inventorying BMP implementation requires establishing a program that tracks the implementation or operation and maintenance of all BMPs of certain types (e.g., septic tanks and erosion and sediment control practices). The guidance can help state and local governments by providing a subset of controls, both structural and nonstructural, that can be sampled for: inspection programs, maintenance oversight, and implementation confirmation.