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Storm Water Requirements FAQ
View frequently asked questions regarding Storm Water (SWMP) Requirements for New Development and Redevelopment below.
| New or Replaced Impervious Surface (Sq Ft) | Tier | Requirement | Detailed Information in TGM |
|---|---|---|---|
| 1 - 499 | 1 | Select and implement one or more Tier 1 BMPs. | Section 1.4.1 and Chapter 2 |
| 500 - 1,999 | 2 | Select and implement storm water BMPs to capture and treat runoff generated from a 1” storm from the new/replaced impervious area (or equivalent area). | Section 1.4.2 and Chapter 2 |
| 2,000 - 14,999 | 3 | Select and implement storm water BMPs to capture and treat runoff generated from a 1” storm from at least 95% of the project site’s impervious area. | Section 1.4.3 and Chapter 6 |
| 15,000 or more | 4 | Select and implement storm water BMPs to meet Tier 3 requirements for Peak Runoff Discharge Rate and Water Quality Treatment. In addition, regarding Volume Reduction, Tier 4 projects must retain/prevent offsite discharge from all storm events up to and including the 95th percentile 24-hour rainfall event, which is currently 2.4” for Santa Barbara. Projects are required to retain the 1.2”, 24-hour rainfall event for all replaced impervious area and the 2.4”, 24-hour rainfall event for all new impervious area. | Section 1.4.4 and Chapter 6 |
Yes. Regardless of whether a project is discretionary or ministerial, all projects that propose new and/or replaced impervious area or qualify as a public improvement in the right-of-way (see definition in Appendix A of TGM) must comply.
All projects that propose new and/or replaced impervious area or qualify as a public improvement in the right-of-way (see definition in Appendix A of TGM) will be routed for compliance review.
For Tier 2, Tier 3, and Tier 4 projects, hiring a Civil Engineer to demonstrate compliance with the requirements is recommended but not required. An architect or other design professional may produce the analysis.
Yes. Infiltration is required unless it is not feasible due to contamination, high ground water, soils with insufficient infiltration rates, slopes, or other safety concern identified in writing by a licensed Geotechnical Engineer.
For discretionary projects, compliance with all storm water treatment requirements must be demonstrated prior to Design Review Final Approval. Projects that require Planning Commission review must submit a storm water report and grading and drainage plan that demonstrates compliance with requirements before your application will be considered complete. For ministerial projects, compliance will be determined as part of the building permit application review process.
There are various techniques and landscape features that can be used to treat storm water. For more information, please see Chapters 2 and 6 in the TGM.
Yes, if your project is Tier 3 or Tier 4. A template is available in Appendix B of the TGM.
The new ordinance went into effect on March 1, 2021. Applications for ministerial projects submitted on or after March 1, 2021, will be processed under the new requirements. Applications for discretionary projects accepted for processing before December 14, 2020 may, at the applicant’s discretion, be processed under the old or new post-construction requirements. The implementation timeline is intended to provide a bright line trigger (date project application is accepted for processing) for the new program to apply, but also to provide maximum flexibility for applicants who are working their way through the land development process during the transitionary period.
Approved projects with issued building permits that would qualify for a lower Tier under the new requirements (e.g., approved Tier 3 project that would be Tier 2 under the new requirements) could submit revised plans to the Building and Safety Division requesting a review for compliance with the new Tier. Similarly, projects that have not yet been approved (i.e., no issued building permit) that would qualify for a lower Tier under the new requirements are welcome to submit revised plans to Creeks Division staff requesting a review for compliance with the new Tier. Any proposed changes will also require review by City staff in other Divisions, and additional Design Review may be necessary.
No. The new storm water treatment requirements are determined only by the amount of proposed new/replaced impervious area. Please contact Creeks Division staff at SWMP@SantaBarbaraCA.gov for project specific questions.
When determining the square footage for a project Tier determination, removed impervious area will not be subtracted from new/replaced impervious area (not a “net” amount). Although, areas where impervious area is removed are considered self-treating and do not require additional treatment measures. In addition, Tier 3 projects that propose no increase in impervious area do not have to meet the peak runoff discharge rate and volume reduction requirements.
Yes. Infiltration is required unless it is not feasible due to contamination, high ground water, soils with insufficient infiltration rates, slopes, or other safety concern identified in writing by a licensed geotechnical engineer.
When determining the square footage for a project Tier determination, removed impervious area will not be subtracted from new/replaced impervious area (not a “net” amount). Although, areas where impervious area is removed are considered self-treating and do not require additional treatment measures. In addition, Tier 3 projects that propose no increase in impervious area do not have to meet the peak runoff discharge rate and volume reduction requirements.
For Tier 3 projects only, five percent (5%) of all impervious area on site is exempt (i.e., not required to be tributary to storm water treatment BMPs). Tier 4 projects must treat all impervious area on the parcel or project site.
Changes were made to make the program more flexible, equitable, and effective, as well as easier to understand, while also ensuring the City meets the Clean Water Act mandates. Errors and inconsistencies were also corrected.