Martin County, FL Environmental Rules: Stormwater Management (2026)
Key Facts
- Enforcing office
- Martin County Engineer
- Design storms (volume)
- 25-yr 3-day and 3-yr 1-day events
- Peak discharge standard
- No increase over predevelopment rate
- Water quality treatment volume
- 3 in., min. 90% recovery in 12 days
- As-built deadline
- Filed within 60 days of completion
Summary
Martin County requires every new development to hold post-development runoff at predevelopment rate, volume, timing and quality, engineered to control a 25-year, three-day storm and a 3-year, one-day storm under the County Engineer's review. No development order can issue until a licensed engineer certifies full compliance with LDR Divisions 9 and 10.
The purposes of this division are to ensure that development activity: enhances the water quality of downstream water bodies; does not impede or negatively alter the historic flow of stormwater runoff; and does not create additional stormwater runoff, and to promote the public health, safety and general welfare. ... Discharge from the site after development shall have approximately the same rate of flow, volume, timing and quality as runoff that would have occurred following the same rainfall under predevelopment conditions.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 62 | Land Development Regulations: Supplement 62).
Full Breakdown
Land Development Regulations Division 9, Stormwater Management, governs every 'development activity' on a site, from grading and paving to building construction. Sec. ' Sec. A bars the County Engineer from issuing any development order or permit for a newly created lot until the applicant demonstrates compliance with the review standards of Sec. 385. 5 requires retention or detention systems sized to hold the increased runoff a project generates. The hydrologic design criteria in Sec. D set the actual engineering targets: every project must control discharge volume at predevelopment levels for a 25-year frequency, three-day duration storm and a 3-year frequency, one-day duration storm, and the peak discharge rate cannot exceed the predevelopment rate for the 25-year, three-day event.
Sec. F adds water-quality treatment requirements, generally a three-inch treatment volume recovered within 12 days of a storm. Every application must include an engineer of record's signed certification, quoted verbatim in Sec. S. Army Corps of Engineers. Sec. 386 requires an approved maintenance plan, with an as-built plan filed with the County Engineer within 60 days of completion and a signed maintenance report before construction bonds are released.
Violations & Fines
Development orders and permits are withheld outright until the Sec. 4.385 standards and the engineer's certification are satisfied; Sec. 4.385.B.9 separately bars altering, dredging or filling a natural watercourse without County Engineer approval, and draining into a county-owned stormwater outfall under Sec. 4.385.B.10 requires that same prior approval before it can occur.
Frequently Asked Questions
What runoff standard must new development in Martin County meet?
Who signs off on a stormwater management plan in Martin County?
Can I discharge into a county drainage outfall without permission?
Sources & Official References
Other rules in Martin County
Florida rules heatmap·Compare Martin County to another location·View the Florida environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.