Florida Diesel Storage Tank Rules: AST Thresholds, SPCC & Fire Code

Florida diesel storage tanks are regulated on a sliding scale: the state Department of Environmental Protection (FDEP) generally regulates aboveground tank systems storing more than 550 gallons of diesel, federal EPA spill rules kick in above 1,320 gallons of aggregate aboveground capacity, and your local fire marshal enforces the fire code on top of both. Here is how those thresholds stack up.

If you keep diesel on your property in Florida — for a fleet yard, a construction laydown area, a farm, or a backup generator — your storage tank sits inside a layered set of rules from three different authorities. None of them are optional, and the penalties for getting them wrong range from registration fines to full remediation liability if a tank leaks. This guide walks through the **diesel storage tank regulations** that most Florida operators need to know, from the FDEP registration threshold to secondary containment, spill prevention, and the county fire-code touchpoints that catch people off guard. Treat this as general orientation, not legal advice — your specific tank, site, and county determine your exact obligations, and the authority having jurisdiction always has the final word.

The Three Authorities That Regulate Your Tank

Diesel storage in Florida is governed by three overlapping layers. The Florida Department of Environmental Protection (FDEP) administers the state Storage Tank Program under Chapter 62-762 of the Florida Administrative Code, which covers aboveground storage tank (AST) systems. The federal Environmental Protection Agency (EPA) administers the Spill Prevention, Control, and Countermeasure (SPCC) rule under 40 CFR Part 112, aimed at preventing oil from reaching navigable waters. Finally, your local authority having jurisdiction — usually the county or municipal fire marshal — enforces the Florida Fire Prevention Code, which adopts NFPA 30 (Flammable and Combustible Liquids Code).

These three layers have different triggers and different thresholds. A tank can be small enough to skip FDEP registration but still fall under a fire-code permit, or large enough for both FDEP and SPCC. You have to check each one independently rather than assuming a single number clears you.

FDEP Registration and the 550-Gallon AST Threshold

Under Chapter 62-762, FDEP's aboveground storage tank rules generally apply to AST systems with an individual tank capacity greater than 550 gallons that store a regulated substance — and diesel fuel is a regulated substance. If your aboveground diesel tank holds more than 550 gallons, you typically must register the storage tank system with FDEP (in most counties this is administered through a delegated local program), pay the applicable registration and annual fees, and keep the tank in compliance with the program's construction, monitoring, and closure standards.

Registration is not a one-time formality. Registered tank systems are subject to periodic compliance inspections, release-detection expectations, and formal requirements when you install, upgrade, or permanently close a tank. Underground storage tanks (USTs) are regulated under a companion chapter (62-761) with a lower size trigger and stricter monitoring, which is one reason many Florida operators choose aboveground tanks — the AST rules are generally more workable for on-site fueling.

What "regulated substance" and "capacity" mean

Capacity refers to the tank's design volume, not how much fuel you happen to keep in it. A 1,000-gallon tank you only fill halfway is still a 1,000-gallon tank in the eyes of the rule. And because diesel is a regulated substance, there is no "it's just diesel" exemption — the same tank storing potable water would not be regulated, but diesel pulls it into the program.

The Federal SPCC Rule and the 1,320-Gallon Threshold

The EPA's SPCC rule operates on a completely separate trigger from FDEP. If your facility has an aggregate aboveground oil storage capacity greater than 1,320 gallons — counting all containers of 55 gallons or larger combined, not just your diesel tank — and could reasonably be expected to discharge oil into navigable waters or adjoining shorelines, you generally need an SPCC Plan.

"Aggregate" is the word that surprises people. Three separate 500-gallon diesel tanks total 1,500 gallons and cross the SPCC line even though no single tank does. Drums, day tanks, and generator belly tanks all count toward the total. An SPCC Plan documents your tank inventory, containment measures, inspection routines, and spill response procedures. Smaller "qualified facilities" can often self-certify the plan; larger facilities generally need it certified by a licensed Professional Engineer.

Secondary Containment and Spill Prevention Basics

Secondary containment is the single most important physical control on a diesel AST, and it is where FDEP standards, SPCC, and NFPA 30 all converge. The governing idea is simple: if the tank fails, the fuel has to go somewhere that is not the ground, a storm drain, or a waterway.

- **Sized containment:** Containment for a single tank is generally designed to hold the full volume of the largest tank plus a margin for rainfall — the common design benchmark is 110 percent of the largest tank's capacity for open containment areas. - **Impervious barrier:** Dikes, berms, concrete vaults, or double-walled tanks must keep released fuel from soaking into soil. Many modern Florida ASTs use double-wall or "vaulted" construction that builds containment into the tank itself. - **Overfill and spill protection:** Fill points need overfill alarms or automatic shutoff and a spill bucket at the connection to catch drips during delivery. - **Rainwater management:** Open containment areas collect rain, so you need a controlled way to drain clean water without releasing any accumulated fuel sheen.

Good delivery practice reinforces the hardware. A professional fuel supplier grounds the truck, uses calibrated meters, watches the fill against your tank gauge, and documents the drop — which is part of why sourcing your fuel through a broker that provides certified meter readings and proof-of-delivery photos matters for compliance as much as for billing.

County Fire-Code Touchpoints

Even when a tank is registered with FDEP and covered by an SPCC Plan, the local fire marshal is a separate stop. The Florida Fire Prevention Code adopts NFPA 30, which governs how combustible liquids like diesel are stored, how far tanks must sit from buildings and property lines, tank spacing, venting, and whether you need a permit and an inspection to install or operate the tank.

Local requirements vary meaningfully from county to county and city to city. Some jurisdictions require a construction permit before a tank goes in the ground or on a pad; others require an annual operational permit; many require the fire marshal to sign off on setbacks and containment before you take a single delivery. Because these are local overlays on the state fire code, the only reliable way to know your obligations is to contact your county or municipal fire marshal's office directly.

When to Consult the AHJ (and Other Professionals)

The authority having jurisdiction — the AHJ — is the official empowered to interpret and enforce the code on your specific site. You should reach out to your AHJ before you install a new tank, before you relocate or resize an existing one, and any time you are unsure whether a permit applies. It is far cheaper to ask first than to install a non-compliant tank and be ordered to move or remove it.

For anything touching liability, closure, or a suspected release, bring in the right professionals: an environmental consultant or licensed PE for SPCC and tank design, and legal counsel for questions about liability and reporting. This guide is a starting map, not a substitute for the AHJ's determination or professional advice tailored to your facility.

How the Thresholds Stack Up

Here is the practical summary. Below 550 gallons aboveground, you are generally outside FDEP's AST registration program but may still face fire-code permitting locally. Above 550 gallons, plan on FDEP registration and its inspection and monitoring expectations. Above 1,320 gallons of aggregate aboveground capacity, plan on a federal SPCC Plan on top of everything else. And at every size, the local fire marshal's adoption of NFPA 30 governs siting, setbacks, and permits. When in doubt, contact the AHJ first — then build your tank to satisfy the strictest applicable layer.

If you would rather not own the storage-and-compliance burden at all, on-site delivery is the alternative many Florida operators choose: a broker brings metered diesel directly to your equipment and tanks on a schedule, so you keep less fuel on hand and generate clean documentation for every gallon. To talk through tank fills, bulk drops, or a delivery plan sized to your site, request a quote from BettyJet Fuel or call (813) 694-8898.