Orange County, FL Environmental Rules: Stormwater Management (2026)
Key Facts
- Categories
- Category 1, 2, or 3 by size/impervious cover
- Pollution abatement
- Retain/filter first 1/2 inch runoff or 1-inch rain
- Recharge trigger
- 25-yr, 24-hr storm retention, Category 3 only
- Discharge cap
- No increase over predevelopment 25-year peak rate
- No-outfall sites
- Must retain full 100-year storm runoff on site
- Maintenance
- Owner responsible unless county accepts the facility
- Waiver
- Available for sites in master-drained commercial/industrial subdivisions
Summary
Unincorporated Orange County requires an engineered stormwater management system on every new development before construction begins. Code § 30-277 sorts projects into three categories by size and existing impervious cover, and each category triggers its own pollution-abatement, aquifer-recharge, discharge-rate and flood-protection standards, all reviewed and approved by the county engineer before drainage plans clear permitting.
(a)A stormwater management system shall be designed and installed for the development that will contain features to provide for:(1)Pollution abatement (Categories 1, 2 and 3).(2)Recharge, where possible (Category 3 only).(3)Rate of discharge limitations (Categories 2 and 3).(4)Protection from flooding (Categories 2 and 3).(c)Pollution abatement will be accomplished by retention, or detention with filtration, of one-half inch of runoff from the developed site, or the runoff generated from the first one (1) inch of rainfall, on the developed site. The volume of runoff generated from the first inch of rainfall shall be estimated by multiplying the Rational Method Runoff Coefficient (C) for the developed site by one (1) inch of rainfall.(e)The post development peak rate of discharge permitted from the site will not exceed the predevelopment peak rate of discharge from the site during a twenty-five-year frequency storm event. Those sites with no positive outfall will be required to retain total runoff from a one-hundred-year storm event.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 128).
Full Breakdown
Section 30-276 splits development into three categories: Category 1 is a site that already has mostly impervious area and adds none; Category 2 is anything else under ten acres; Category 3 is ten acres or more. Under § 30-277(a), every category must provide pollution abatement, Category 3 sites must provide aquifer recharge "where possible," and Categories 2 and 3 must limit their rate of discharge and protect against flooding. Pollution abatement, § 30-277(c), is met by retaining or filtering the first one-half inch of site runoff, or the runoff from the first inch of rainfall, calculated with the Rational Method Runoff Coefficient.
Where soils are Hydrologic Group "A," § 30-277(d) requires recharge facilities sized to retain the full runoff from a twenty-five-year, twenty-four-hour storm. Section 30-277(e) caps the post-development peak discharge rate at the predevelopment rate for a twenty-five-year storm; a site with no positive outfall must instead retain its entire one-hundred-year storm volume on site. Section 30-277(f) requires residential structures to be flood-free and commercial or industrial structures to be flood-free or floodproofed. Section 30-278 adds that off-site drainage easements are required whenever a project discharges into a county facility without an existing drainage easement or right-of-way, or changes the character of flow into a natural system, and outlet structures must include features to minimize floating debris, oil and grease.
Section 30-277(b) lets the county engineer waive these requirements for an individual site inside a commercial or industrial subdivision that already has an approved master drainage system. Section 30-282 requires the construction plans to include a full drainage map, a geotechnical subsoil report with at least two borings per retention/detention area, and stormwater and routing calculations for both the 25-year/24-hour and 100-year/24-hour storm events before the county engineer will approve the project.
Violations & Fines
These standards are enforced at the permitting counter, not after the fact: § 30-282 requires the drainage map, subsoil report and storm-event calculations to reach the county engineer's desk before construction plans are approved, so a design that misses the pollution-abatement or discharge-rate targets in § 30-277 does not get built. Once built, § 30-280(e) makes the property owner responsible for operating and maintaining the stormwater facility unless the county has formally accepted it, and § 30-278(b) requires the developer to record an off-site drainage easement wherever the project discharges into a county facility or an unpermitted natural system.
Frequently Asked Questions
Do these stormwater rules apply to my address in Orlando or Winter Park?
What size project triggers the strictest Category 3 review?
Can the county waive these stormwater design standards?
What if my site has nowhere for stormwater to drain?
Sources & Official References
Other rules in Orange County
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