Construction Site Runoff Control

Federal, State & Local Regulations

There are two National Pollutant Discharge Elimination System (NPDES) permits that regulate polluted runoff from construction sites:

• NPDES Construction General Permit
• NPDES Municipal General Permit

NPDES Construction General Permit

Significant new requirements!

Any property owner whose project disturbs one acre or more of soil is required to obtain coverage under the General Permit for Discharges of Storm Water Associated with Construction Activity.  Construction activity subject to this permit includes clearing, grading and disturbances to the ground such as stockpiling or excavation but does not include regular maintenance activities performed to restore the original line, grade or capacity of the facility.

You can learn more about the General Permit at the State Water Resources Control Board's website.

NPDES Municipal General Permit

All of the incorporated and unincorporated areas within the Napa River watershed are covered under the Phase II NPDES Municipal General Permit.  Under this permit, the Napa Countywide Stormwater Pollution Prevention Program (NCSPPP) partners are required to develop, implement and enforce a program to reduce pollutants from construction sites among many other requirements.  This program includes the following:

• Legal authority to establish best management practice (BMP) requirements
• Procedures for site plan review
• Procedures for receiving complaints from the public
• Procedures for inspection and enforcement

You can learn more about the local requirements for each of the NCSPPP partners as well as the use of BMPs to control pollution from construction sites by contacting the municipality in which your project is located.