Grease Trap and Interceptor Requirements in Florida

Grease trap and interceptor systems are a mandatory component of Florida's commercial plumbing infrastructure wherever food service, industrial, or institutional operations discharge fats, oils, and grease (FOG) into municipal wastewater systems. Florida's warm climate accelerates grease congealing and biological activity in drainage lines, making FOG management a more pressing operational and regulatory concern than in cooler states. Requirements span the Florida Building Code (FBC), local utility authority rules, and environmental standards enforced through the Florida Department of Environmental Protection (FDEP) — with enforcement authority distributed across multiple agencies.

Definition and scope

A grease trap — also called a grease interceptor — is a plumbing device designed to intercept and retain fats, oils, and grease before they enter a sanitary sewer system. The Florida Building Code, Plumbing volume, incorporates provisions from the International Plumbing Code (IPC) as its base, with Florida-specific amendments governing sizing, installation depth, and maintenance intervals.

Two primary device classifications govern Florida installations:

• Hydromechanical Grease Interceptors (HGI) — Smaller, passive units typically installed under sinks or counters inside the facility. These are rated by flow capacity (in gallons per minute, or GPM) and are governed by ASME A112.14.3, the standard for hydromechanical grease interceptors established by the American Society of Mechanical Engineers (ASME).
• Gravity Grease Interceptors (GGI) — Large, underground vault systems installed outside the building. Capacities are measured in gallons of static volume (commonly 500 to 2,000 gallons or more) and are governed by ASME A112.14.6 for factory-made units. PDI (Plumbing & Drainage Institute) Standard PDI-G101 also applies to hydromechanical devices.

Scope for this page is limited to Florida state-level requirements and the FBC plumbing provisions as they apply within Florida's 67 counties. Federal pretreatment standards issued by the U.S. Environmental Protection Agency (EPA) under 40 CFR Part 403 (EPA Pretreatment Regulations) establish the national baseline but are administered locally through municipal pretreatment programs — those local utility authority rules are not fully addressed here and vary by jurisdiction. Facilities subject to FDEP industrial wastewater permits operate under a separate regulatory track not covered on this page.

How it works

Grease interceptors function through gravity separation. Wastewater enters the device from the kitchen or process area, slows significantly as it enters the larger chamber, and separates into three layers: a floating FOG layer on top, a relatively clear effluent layer in the middle, and a settled solids layer on the bottom. Only the middle effluent layer exits through the outlet baffle into the sewer system.

The operational sequence for a properly functioning gravity interceptor:

1. Inlet flow — Wastewater enters through the inlet baffle, which directs flow downward to minimize turbulence and FOG disturbance.
2. Retention and separation — The tank's hydraulic retention time (HRT) allows density-based separation. HRT in a properly sized GGI is typically 30 minutes or greater under peak flow conditions.
3. Effluent discharge — Clarified effluent exits through a submerged outlet pipe, preventing the floating FOG layer from passing downstream.
4. Accumulation management — FOG and solids accumulate over time and must be pumped out before they occupy more than 25 percent of the interceptor's working volume — a threshold specified by PDI standards and commonly adopted in Florida local utility authority FOG ordinances.

For hydromechanical units, a flow control fitting upstream of the device regulates inlet velocity to match the unit's rated GPM capacity, preventing bypass of unprocessed grease.

Common scenarios

The broadest application category for grease interceptors in Florida is food service establishments, including restaurants, institutional cafeterias, hotel kitchens, and food processing facilities connected to municipal sewer systems. A full-service restaurant generating 200 or more seat-hours per day typically requires a gravity interceptor of at least 1,000 gallons under local utility authority FOG control programs in jurisdictions such as Miami-Dade, Broward, and Orange counties.

Additional scenarios where Florida code and utility rules require interceptors:

• Car wash and vehicle service facilities — Require sand and oil interceptors (distinct from FOG interceptors) under FBC Plumbing provisions, governed by ASME A112.14.4.
• Meat and seafood processing — Florida's seafood processing industry, concentrated along Gulf Coast counties, generates high-FOG waste streams subject to both FBC requirements and FDEP industrial pretreatment thresholds.
• Healthcare facility kitchens — Hospital and nursing home food preparation operations are subject to interceptor requirements even when food service is not the primary business classification.
• Mobile food dispensing vehicles (MFDVs) — Florida's MFDV operators must demonstrate compliant grease disposal through licensed waste haulers when operating in jurisdictions that do not permit direct sewer connection from mobile units.

For permitting intersections specific to Florida commercial plumbing standards, the local building department issues the plumbing permit while the local utility authority independently enforces FOG compliance — these are parallel approval tracks, not sequential ones.

Decision boundaries

Selecting the correct device type and sizing method requires resolution of at least four threshold questions before permit application:

1. Indoor vs. outdoor installation — HGIs are used where below-grade outdoor installation is not feasible (limited lot space, high water table). Florida's coastal and South Florida markets frequently default to HGIs for retrofit installations due to water table constraints. For foundation-related plumbing considerations, the Florida slab foundation plumbing reference covers related depth and access constraints.
2. Sizing authority — The FBC defers sizing to PDI-G101 tables for HGIs, which calculate required flow rate in GPM based on fixture units and drain load. GGI sizing follows local utility authority standards, which in Florida typically use the Uniform Plumbing Code (UPC) Appendix H methodology or locally derived formulas — these two methods can produce different results for the same facility.
3. Maintenance interval enforcement — Local utility FOG programs in Florida generally require pumping records to be retained for a minimum of 3 years and made available for inspection. Non-compliance can trigger notice of violation under local pretreatment ordinances independently of any building code enforcement action.
4. New construction vs. retrofit — New construction triggers full FBC permitting and inspection. Retrofit installations — including grease trap replacements — also require permits in most Florida jurisdictions; unpermitted replacements are a documented source of enforcement actions by local building departments.

The Florida Plumbing Authority index provides orientation to the full scope of plumbing regulatory categories in Florida, including cross-references to backflow prevention, water conservation, and commercial plumbing standards that intersect with FOG system design. For the broader regulatory framework governing these installations, the regulatory context for Florida plumbing page maps the agency structure across DBPR, FDEP, and local enforcement authorities.

References

• Florida Building Code — Plumbing Volume (Florida DBPR)
• Florida Department of Environmental Protection (FDEP) — Wastewater
• U.S. EPA Pretreatment Regulations, 40 CFR Part 403
• ASME A112.14.3 — Hydromechanical Grease Interceptors (American Society of Mechanical Engineers)
• PDI-G101 — Grease Interceptors (Plumbing & Drainage Institute)
• Florida Department of Business and Professional Regulation (DBPR)