Storm Water

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If you observe any overflowing manholes, sewer line back ups, obstructions, or missing manholes/storm drain grates, please report them to 538-2415 immediately. For emergencies after 3:30pm, weekends, or holidays please call 538-2448.

As properties develop within the City, vegetation is removed and replaced with impervious surfaces. These surfaces include streets, parking lots, and rooftop areas. The amount of storm water runoff after a property develops increase for two reasons: (1) there is less vegetation and exposed ground to soak up the water, and (2) the storm water leaves the property faster and at higher concentrations because water flows more quickly over concrete and asphalt surfaces than grassy fields. Urban runoff frequently carries various forms of pollution such as rubbish, animal droppings and dissolved chemicals. This untreated water is carried through a system of underground pipes or overland channels, and eventually discharges directly into creeks and rivers. To accommodate for these impacts, the City requires installation of storm water detention ponds or underground storage tanks to hold back the peak of the storm, and in many instances requires installation of mechanical or biological treatment units to remove trash and other storm water pollutants. Additional mitigation required by the City includes a Storm Water Pollution Prevention Plan (SWPPP) during construction projects that are one acre or larger.

EPA Phase II Storm Water Regulations

The City Oroville in the future may become part of the Phase II Environmental Protection Agency (EPA) Storm Water Regulations Program as part of a smaller community designation by the State of California. Those communities permitted under Phase II are required to develop and implement a comprehensive storm water management program that includes six minimum measures to promote storm water pollutant load reduction. These are:

  • Public education - this includes the distribution of educational materials andStorm Water Discharge

  • performing outreach to inform citizens of reasons to control storm water runoff
  • Public participation and involvement - this includes providing opportunities for citizens to participate in storm water program development and implementation
  • Illicit discharge detection and elimination - this element includes developing and implementing a plan to detect and eliminate illicit discharges to the storm water system
  • Construction site runoff control - this includes developing, implementing, and enforcing a sediment and erosion control program for construction activities; which the city already enforces
  • Post-construction runoff control - this element includes developing, implementing, and enforcing a program to address discharges of post-construction runoff and specifies appropriate storm water treatment practices (STPs); and
  • Pollution prevention and good housekeeping - this includes developing and implementing a program with the goal of preventing or reducing pollutant runoff from municipal operations.

To gain a more in depth understanding of the proposed EPA regulations, please visit their web site and read their proposed regulations:

Environmental Protection Agency Web Site:

Storm Water Infrastructure

The City of Oroville currently maintains approximately 60 miles of storm water drainage pipes and trenches, thousands of manholes and drop inlets, plus six regional detention basins. Storm water drainage infrastructure is essential to the safety of Oroville's citizen and their property. The City's storm water infrastructure is designed and engineered to protect residents in the occurrence of a extreme hydrologic event or more commonly known as a 100 year storm event. For a more in depth description of a extreme hydrologic event please visit this website, authored by the U.S. Geological Survey (USGS). Associated with storm drainage infrastructure are engineering documents know as as-builts. Our library of storm drain as-builts can be found here

Erosion Control Permits, Grading Permits, & Storm Water Pollution Prevention Plan (SWPPP)

Grading and erosion control permits are required by anyone moving soil on a site, importing or exporting soil to or from a site, or performing a land disturbance activity such as stockpiling, clearing or grubbing. The table below explains the different triggers for the different permits and plans.

Less the 20 cubic yards/Less than 200 square feet
on a parcel with a slope less than 10%
Small Grading Project 20-49 cubic yards/99-200 square feet Erosion Control Permit
Medium Grading Project 50 cubic yards and above/1,000 square feet -1 acre Grading Permit
Large Grading Project Soil disturbance of 1 Acre or larger SWPPP & Grading Permit


Grading Permit Fees can be found here

All grading and land disturbance activities must be done using Best Management Practices (BMPs) that are consistent with the City design standards, and consistent with the latest version of the California Storm Water Quality Construction Handbook, published by the California Storm Water Quality Association. Certain grading projects require the preparation of an environmental review through the California Environmental Quality Act (CEQA). Projects that disturb soil over 1 acre in size requires the preparation of a Storm Water Pollution Prevention Plan(SWPPP) for submittal to the Central Valley Regional Water Quality Control Board (CVRWQCB). Financial securities are required for large grading projects.

Storm Water Pollution Prevention Plan (SWPPP)

As required by the CVRWQCB, the City of Oroville requires a SWPPP to be prepared before the start of any construction projects one acre or larger and before the issuance of a grading permit. For a in-depth explanation of SWPPP guidelines please view the following document:

California State Water Resources Control Board:

Construction Activities Storm Water General Permit Order No. 99-08-DWQ

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