The City of Napa’s General Plan, Envision Napa 2020,  establishes a general goal of a restored, healthy, living Napa River, which is the vibrant central defining feature of the Downtown and the City of Napa. 

The City of Napa is required by the Federal Clean Water Act to obtain a permit to discharge storm water. This General Permit requires the City of Napa to:

• Develop and implement a  Storm Water Management Plan (SWMP) that describes  Best Management Practices (BMPs), measurable goals, and timetables for implementation in the following six program areas (Minimum Control Measures):

1. Public Education: The City of Napa must educate the public in its permitted jurisdiction about the importance of the storm water program and the public’s role in the program.
2. Public Parcipation: The City of Napa must comply with all State and local notice requirements when implementing a public involvement/participation program.
3. Illicit Discharge Detection and Elimination: The City of Napa must adopt and enforce ordinances or take equivalent measures that prohibit illicit discharges. The City of Napa must also implement a program to detect illicit discharge.
4. Construction Site Storm Water Runoff Control: The City of Napa must develop a program to control the discharge of pollutants from construction sites greater than or equal to one acre in size within its permitted jurisdiction. The program must include inspections of construction sites and enforcement actions against violators.
5. Post Construction Storm Water Management: The City of Napa must require long-term post-construction BMPs that protect water quality and control runoff flow, to be incorporated into development and significant redevelopment projects. Post-construction programs are most efficient when they stress (i) low impact design; (ii) source controls; and (iii) treatment controls.
6. Pollution Prevention/Good Housekeeping for Municipal Operations: The City of Napa must examine its own activities and develop a program to prevent the discharge of pollutants from these activities. At a minimum, the program must educate staff on pollution prevention, and minimize pollutant sources.

To more effectively reduce storm water pollution in the Napa River watershed the City of Napa joined with the Cities of American Canyon, St. Helena, Calistoga; Town of Yountville and Napa County to establish a county-wide storm water pollution program.

The Napa County Stormwater Management Program (NCSWMP) is a joint effort of Napa's cities, towns and unincorporated areas to:

• Prevent storm water pollution
• Protect and enhance water quality in creeks and wetlands
• Preserve beneficial uses of local waterways
• Comply with State and Federal regulations

Though the County and each of the five cities and towns carry out their own individual storm water pollution prevention programs, NCSWMP provides for the coordination and consistency of approaches between the individual participants and documents their efforts in annual reports.

NCSWMP is funded by the member agencies and is administered by the Napa County Flood Control and Water Conservation District.

To reduce pollution and meet permit requirements the City of Napa adopted Chapter 8.36, Stormwater Runoff Pollution Control Ordinance, on June 15, 2004. 

Post Construction Best Management Practices, Measure 5 (BMP)  guidance for new construction and redevelopment were estabilished June 20, 2006.