Stormwater Requirements for New Construction

Who can use this service?

Anyone applying for a construction permit can use this service.

Is there a charge for this service?

The cost for this service is factored into applicable construction permit fees.

What is the process?

Step 1: Determine Applicable Stormwater Management Requirements

There are two Post-Construction Stormwater standards currently in effect in San Luis Obispo County. The post-construction stormwater requirements summary chart summarizes the requirements and their applicability. Planning and Building staff can help determine which requirements apply to the project.

Within the Phase II Municipal Permit Area (the County’s Stormwater Management Area) the County applies the Central Coast Post-Construction Requirements. Projects located outside the Stormwater Management Area (in unincorporated areas of the county) that disturb more than 1.0 acre must meet the Post-Construction Standards in the California Construction General Permit.

The County’s Land Use View mapping application can help you determine which standard applies to your project based on the site location.

Step 2: Incorporate Stormwater Management into Plans/Designs

Post-Construction stormwater treatment and retention requirements should be incorporated into the site design at the planning stage. Projects within the County’s Municipal Stormwater Management Area (MS4 Coverage Area) must adhere to the Central Coast Post Construction Requirements.

Permit applicants must submit either: 

Projects that meet the criteria for implementing Performance Requirement 2 or above are required to submit a Stormwater Control Plan. Please use the Stormwater Control Plan template provided to facilitate timely review. Public Works staff will review the post-construction stormwater management designs during the plan check process.

The San Luis Obispo County Low Impact Development Handbook provides guidance on designing stormwater management controls. 

Step 3: Use Stormwater Management Controls During Construction

Building inspectors will monitor the condition of Best Management Practices (BMPs) during the construction process. Inspectors will issue correction notices to site managers if BMPs are deficient or require repair. Failure to make corrections or remedy failing BMPs subjects the site to permit suspension or stop-work orders.
Sites that disturb 1.0 acre or more must enroll for coverage under California’s Construction General Permit. Sites that disturb less than 1.0 acre must implement all required elements within the site’s erosion and sediment control plan as required by San Luis Obispo County Codes.

Step 4: Create a Post-Construction Plan

The Construction General Permit and the Central Coast Post-Construction Requirements mandate that applicants create an Operations and Maintenance Plan for any features that are installed to mitigate post-construction stormwater runoff.  


Projects outside the Stormwater Management Area that enroll in the Construction General Permit must submit an Operations and Maintenance Plan as a component of the site’s Stormwater Pollution Prevention Plan. 
Projects within the County’s Stormwater Management Area must record an Operations and Maintenance Plan with the Department of Planning and Building. Please refer to post-construction stormwater management for additional information.

When and where is this service offered?

This service is available throughout the year during regular business hours except during scheduled holidays.

Location, directions and hours of operation

Click on location name to show hours of operation, directions and phone information

Old County Courthouse Building

Monday - Friday 8:30 AM - 4:30 PM

976 Osos Street Room 200 San Luis Obispo, CA 93408

Tel: (805) 781-5600

Permits/Inspections: (805) 788-2076

Fax: (805) 781-1242

Frequently Asked Questions

Do I need to enroll in the California Construction General Permit for Stormwater Discharge?
Sites that disturb more than 1.0 acre or are part of a common plan of development must enroll for coverage. For more information about whether a site must enroll for coverage, please review the California Construction General Permit FAQs.
Where can I find information about designing stormwater structural control measures?

The following online resources provide guidance specific to implementing low impact development for stormwater in California or the Central Coast:

Where can I find more information?

For more information on post-construction stormwater runoff management requirements and Low Impact Development please visit the Stormwater Management Post-Construction page. For more information on construction stormwater Best Management Practices and County requirements during construction, please visit the Construction Site Stormwater Management page.

Which post-construction stormwater requirements apply to my site?

The County’s online Land Use View application can help determine which standard applies based on the location of the project. To check the status of a property:

  1. Type the parcel number of the property into the ‘Search’ box in the upper right, then select the parcel information that appears on the bottom of the screen to highlight the parcel. 
  2. Locate the ‘Filter Layers…’ box on the left hand side, type MS4 into the box, and press enter. Select the checkbox for ‘MS4 Coverage Areas’ that appears in the menu below to turn on the map layer.

If the parcel is covered by the MS4 Coverage Area, then the Central Coast Post Construction Requirements are applied. Parcels not included in the MS4 Coverage Area will be subject to the requirements of the California Construction General Permit.

Property Information

Our interactive Land Use View mapping application can be used to look up property information by assessor parcel number (APN) or address.

Launch Application


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