Local goverment operations conduct numerous activities that may pose a threat to water quality if practices and procedures are not in place to prevent pollutants from entering the stormwater conveyance. These activities include winter road maintenance, minor road repairs and other infrastructure work, automobile fleet maintenance, landscaping and park maintenance, and building maintenance. Municipalities also conduct activities that remove pollutants from the MS4 when performed properly, such as parking lot and street sweeping and storm drain system cleaning. Finally, municipal facilities can be sources of stormwater pollutants if BMPs are not in place to contain spills, manage trash, and handle nonstormwater discharges. This table lists the pollutants that are typically associated with municipal facilities and municipal activities [pdf]

Phase II MS4 entities are required to train staff on ways to protect stormwater, particularly when maintaining MS4 infrastructure and performing daily municipal activities, such as park and open space maintenance, fleet and building maintenance, new construction and land disturbances, and stormwater system maintenance. This primarily includes:

• Developing inspection and maintenance procedures and schedules for stormwater BMPs,
• Implementing BMPs to treat pollutants from transportation infrastructure, maintenance areas, storage yards, sand and salt storage areas, and waste transfer stations,
• Establishing procedures for properly disposing of pollutants removed from the MS4 body
• Identifying ways to incorporate water quality controls into new and existing flood management projects.