What Size Grease Trap Does Your South Florida Restaurant Actually Need?
You found the space. The lease is signed. Your contractor is already sketching out the kitchen layout. Then someone — your plumber, your inspector, your health department contact — mentions a grease trap, and suddenly you’ve got a whole new set of questions you weren’t expecting to deal with.
Do you need one? What size? Does it go inside the kitchen or outside? Who installs it? And what happens if you get it wrong?
If you’re opening or renovating a restaurant, hotel kitchen, food truck commissary, school cafeteria, or any other commercial food service operation in South Florida — this guide will walk you through everything you need to know. No jargon, no runaround. Just the real information so you can make a smart decision before your buildout is too far along to change course.
What Is a Grease Trap and Why Does Every Commercial Kitchen in Florida Need One?
A grease trap — also called a grease interceptor — is a plumbing device that captures fats, oils, and grease (FOG) before they make their way into the municipal sewer system or your septic system.
Here in South Florida, FOG is a bigger problem than it might be in other parts of the country. The heat speeds up the breakdown of grease into compounds that are harder on pipes and harder on the infrastructure downstream. Miami-Dade’s sewer system wasn’t exactly built for unlimited capacity, and when restaurants skip proper grease management, the whole system feels it.
That’s why Florida requires grease traps for virtually every commercial food service operation, including:
- Restaurants of all sizes
- Hotel and resort commercial kitchens
- Hospital and institutional cafeterias
- School and university food prep facilities
- Food truck commissary kitchens
- Catering operations and ghost kitchens
- Meal prep and food production facilities
The Florida Department of Environmental Protection (FDEP) and local municipalities enforce these requirements through the Florida Plumbing Code and county-level amendments. In Miami-Dade and Broward County especially, this is actively checked — and showing up to your Certificate of Occupancy inspection without the right grease trap setup can stop your opening in its tracks.
The 3 Main Types of Grease Traps in South Florida
Before you can figure out what size you need, it helps to understand what your options are. The type of grease trap that’s right for your operation depends on your kitchen setup, your daily volume, and what your county actually requires.
1. Hydromechanical Grease Interceptors (HGIs) — Indoor Units
These are the smaller units you’ll see mounted under sinks or above ground near dishwashers and prep sinks inside the kitchen. They’re sized by flow rate — specifically, gallons per minute (GPM) — and are common in smaller restaurants, quick-service spots, and situations where there’s no room for an outdoor tank.
The trade-off with indoor units is maintenance frequency. Because they’re smaller, they fill up faster and need to be cleaned more often — typically every one to three weeks for a busy kitchen. Skip a cleaning, and you’ll know about it quickly.
2. Gravity Grease Interceptors — Outdoor, In-Ground Tanks
These are the underground tanks installed outside your building, usually in the parking lot or along the utility side of the property. They’re sized by liquid capacity — typically ranging from 500 gallons on the smaller end up to 2,000 gallons or more for high-volume operations.
This is the standard setup for most full-service restaurants in South Florida. Most Miami-Dade and Broward municipalities prefer or outright require a gravity interceptor once you hit a certain seat count or fixture count. They don’t need to be pumped as often as indoor units — usually every 30 to 90 days — but when you do need service, you want a contractor who knows what they’re doing.
3. Automatic Grease Removal Units (AGRUs)
These automated systems skim collected grease on a timer and are typically found in high-end hotel kitchens or retrofit situations where space is extremely limited. They’re less common across South Florida than the first two options, but they’re worth knowing about if you’re working with an unusual layout.
How Grease Trap Sizing Actually Works
This is the part that trips people up. Sizing isn’t just picking a number out of thin air — there’s a real formula behind it, and getting it wrong in either direction creates problems.
Sizing Indoor Units: The GPM Method
For indoor hydromechanical units, size is based on flow rate in gallons per minute. Under the Florida Plumbing Code, this is calculated from the drainage flow rate of your fixtures.
A simplified look at how that plays out in practice:
| Kitchen Setup | Approximate GPM Needed |
|---|---|
| Small café, 1–2 sinks, no dishwasher | 20–35 GPM |
| Quick-service restaurant, 2–3 sinks, dishwasher | 35–50 GPM |
| Full-service restaurant, full line, 3-comp sink | 50–100 GPM |
| High-volume restaurant or catering facility | 100+ GPM |
The unit you install needs to be rated at or above your calculated GPM. Undersizing is the most common mistake — and it means your grease trap maxes out faster than expected, leading to backups, overflows, and the kind of health code violations that don’t just go away on their own.
Sizing Outdoor Units: The Gallon Capacity Method
For outdoor gravity interceptors, size is measured in gallons of liquid capacity. Miami-Dade and Broward municipalities typically work from a formula that factors in meals served per day, gallons of water used per meal, and a retention time factor.
For most mid-size full-service restaurants in South Florida, that math lands somewhere in the 750 to 1,000 gallon range as a starting point. High-volume restaurants — the ones doing 300+ covers on a busy Friday night — often need 1,500 gallons or more.
The calculation also accounts for the number of seats you have, the number of plumbing fixtures, whether you’re running a dishwasher or a steam table, and whether you have a drive-through window. Every piece of that kitchen matters.
What Miami-Dade and Broward County Actually Require
Florida doesn’t run a single statewide standard — local counties set requirements within the broader Florida Plumbing Code framework. Here’s what you need to know for South Florida specifically.
Miami-Dade County
Miami-Dade requires grease interceptors for all food service establishments connecting to the public sewer. That means permits, inspections, and compliance with the county’s Water and Sewer Department (WASD) regulations.
Beyond the standard permitting process, Miami-Dade runs an active FOG Management Program aimed specifically at restaurants and commercial kitchens. If your operation generates significant grease volume, you may be required to participate in that program. Violations — meaning operating out of compliance — can mean fines, mandatory corrective action, or in serious cases, suspension of your food service permit. None of those are situations you want to be dealing with during a busy dinner service.
Broward County
Broward follows a similar structure and enforces compliance through both the Building Department and local utility authorities. One thing that catches restaurant owners off guard in Broward is the documentation requirement — many municipalities within the county require you to keep pumping and cleaning logs on-site so inspectors can review them during a health inspection. If you can’t produce records showing your grease trap has been maintained on schedule, that’s a problem even if the trap itself is functioning fine.
Cities within Broward — Fort Lauderdale, Hollywood, Pompano Beach, and others — may layer their own local requirements on top of the county baseline. Always check with your specific municipality before you finalize your plans.
The Practical Takeaway
The right time to figure all of this out is before your plumber roughed in the drain lines, not after. Getting the sizing right from day one means you avoid the scenario where an inspector flags you for an undersized unit and you’re suddenly tearing up a finished floor or cutting into a parking lot you just had paved.
The Most Common Grease Trap Mistakes South Florida Restaurant Owners Make
After years of working with restaurants across Miami-Dade and Broward, we’ve seen the same mistakes come up again and again. Most of them are completely avoidable.
Sizing for your opening menu, not your actual potential You open small, maybe with a stripped-down menu and a tight crew. Six months in, you’ve expanded the kitchen, added a full bar, and your grease trap is struggling to keep up. Always size for where you realistically expect the business to go — not just where it starts.
Going with an indoor unit when the county wants an outdoor one It seems like the simpler, less disruptive option. Then the building inspector or health inspector shows up and tells you an outdoor gravity interceptor is required for your operation. At that point, you’re doing the installation the hard way — after everything around it is already finished.
Leaving the dishwasher and steam table out of the calculation Commercial dishwashers, especially high-temp units, push significant FOG into your drain lines. Steam tables add grease-laden condensate. Both of these need to be in the sizing calculation. Leave them out and you’re starting behind.
Skipping permits An unpermitted grease trap installation is a ticking clock. You probably won’t hear about it until you’re trying to sell the business, renew a license, or survive an inspection. The permit process exists for a reason — work with a contractor who does it properly from the start.
Hiring a general plumber instead of a commercial wastewater specialist Grease trap installation is a different animal from standard plumbing work. You need someone who understands FOG compliance, local code specifics, and the real-world challenges of South Florida’s high water table and soil conditions. Those details matter when you’re installing a buried tank.
How Often Does a Grease Trap Need to Be Cleaned?
Even a perfectly sized grease trap doesn’t take care of itself. Regular cleaning is a legal requirement in most South Florida municipalities — and it’s the difference between a system that does its job and one that becomes a liability.
General guidelines for cleaning frequency:
- Indoor HGIs: Every 1 to 4 weeks depending on volume
- Outdoor gravity interceptors: Every 30 to 60 days for most operations
- High-volume operations: May need service more frequently than the standard schedule
Miami-Dade County’s FOG program recommends pumping your grease interceptor when the grease and solids layer hits 25% of the total liquid depth. Waiting until it’s half full — or fuller — isn’t just a maintenance issue. It’s a compliance issue.
At Above All Wastewater Services, we set up cleaning schedules based on what your kitchen actually produces, not a blanket calendar. If your operation runs hotter and greasier than average, your schedule should reflect that.
Ready to Get Your Grease Trap Right the First Time?
Above All Wastewater Services works with restaurants, commercial kitchens, and food service operations across Miami-Dade, Broward, and Monroe Counties. Whether you’re building something new and need it done right from the start, or you’re running an existing operation that needs a reliable cleaning schedule to stay ahead of inspections — we can help.
Call us at (305) 257-1211 — we’re available 24/7.
We serve Miami, Homestead, Kendall, Coral Gables, Doral, Hialeah, Pinecrest, Palmetto Bay, Cutler Bay, South Miami, Coconut Grove, Key Largo, Florida City, Key Biscayne, Miami Beach, Brickell, Princeton, and the surrounding areas.