Stormwater Management

What is Stormwater Pollution?

Storm drains collect water outside of homes and businesses and channel the water directly to waterways such as local streams and rivers, untreated. More pollutants reach our waterways through the storm drains than through sewage treatment plants and industrial discharges combined.

The Department of Public Works implements measures to reduce and improve water quality by implementing stormwater management throughout the Town of Sudbury. Stormwater runoff is rainwater or melted snow that runs off streets, lawns, and other sites. When stormwater is absorbed into the soil, it is filtered and ultimately replenishes aquifers or flows into streams and rivers.

Impervious surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, water runs rapidly into storm drains, sewer systems, and drainage ditches and can cause:

• Downstream flooding
• Stream bank erosion
• Increased turbidity (muddiness created by stirred-up sediment) from erosion
• Habitat destruction
• Combined storm and sanitary sewer system overflows
• Infrastructure damage
• Contaminated streams and rivers

Town of Sudbury Separate Storm Sewer System (MS4)

The Department of Public Works manages the Town’s Municipal Separate Storm System (MS4). This system, also known as the drainage system, includes drainage pipes connecting to catch basins (also called drains) and drainage manholes. The Town is authorized to discharge stormwater through the Phase II National Pollutant Discharge Elimination System (NPDES) general permit for small MS4s. The United States Environmental Protection Agency (EPA) oversees the NPDES Phase II permitting program. In order to comply with the program, the Town must follow six minimum control measures, which are implemented through a series of Best Management Practices (BMPs).

1. Public education and outreach
2. Public involvement and participation
3. Illicit discharge detection and elimination
4. Construction site stormwater runoff control
5. Post-construction stormwater management
6. Pollution prevention and good housekeeping

Sudbury’s MS4 Drainage System Facts

All figures indicated below are approximations. 

• 60 Miles of Stormwater Drainage Pipe
• 3,000 Catch-basins (public and private)
• 1,800 Manholes (public and private)
• 450 Stormwater Discharge Points
• 100 Culverts
• Ditches and Swales 

Additional Links

• • • Sudbury Stormwater Management Program
    • 2023 Stormwater Management Program Plan (PDF)
    • Sudbury’s Commitment to Clean Water & Stormwater Drainage System Facts (PDF)
    • Stormwater Drainage and Compliance Presentation (PDF)
    • Public Stormwater Map (MapsOnline)
    • Think Blue Massachusetts