Floodplain Development Regulations and Permitting

Always check with the County Planning and Public Works departments before you build, fill, alter or grade on your property.  All new developments, or any alterations, additions, or modifications to your building or land require a permit.  Qualified County staff are available at the Flood Control Counter at the County’s Operation Center at 5510 Overland Avenue, San Diego to discuss your options and to help you plan and build a safe project while complying with the County Flood Damage Prevention Ordinance.

In addition to regular building permits, special regulations apply to construction in the floodplain and floodway. No construction, including filling, is allowed in the mapped floodway without an engineering analysis that shows the project will not increase flood damage elsewhere.  Any activity outside the floodplain but within a natural or man-made watercourse also requires a permit.

Homeowners who are planning substantial improvements should contact the Permit and Review Division for a residential building permit.  Elevation or floodproofing may be required if you plan to substantially improve your existing structure (the cost of the improvement or add-on is 50% of the value of the existing structure).  If your property is substantially damaged (50 percent of the value of the building), Federal regulations may also require you to elevate or floodproof before you can rebuild.

The document titled “Answers to Questions About Substantially Improved/Substantially Damaged Buildings” (FEMA-213, August 2018) will help answer questions on this topic. If you need a hard copy you can call 1-800-480-2520.

To report illegal floodplain development or to verify that proper construction permits have been issued for a project, contact the Department of Public Works Flood Control Counter at (858) 694-2055. An inspector will investigate.

Back to Main Flood Control Home Page

If you have questions or would like additional information, 
call the County Stormwater hotline at 1(888) 846-0800
or e-mail us at watersheds@sdcounty.ca.gov

Report a Stormwater Violation On-Line

If you see a County storm drainage system in need of maintenance, contact the County Department of Public Works Field Operations staff at (619) 443-1260 weekdays or contact the Stormwater Hotline at 1(888) 846-0800.  For after-hours emergencies contact (858) 565-5262. 

Department of Public Works
Flood Control
5510 Overland Ave., Suite 410, MS O-332
San Diego,  CA  92123,  USA
(858) 495-5318           Fax: (858) 495-5263