Grease Trap vs Grease Interceptor: What's the Difference

Grease traps and grease interceptors serve the same core purpose — they capture fats, oils, and grease (FOG) before wastewater enters the municipal sewer system. However, they differ significantly in size, installation location, capacity, cost, and maintenance requirements. Understanding these differences is critical for Florida food service operators choosing the right system and staying compliant with Chapter 62-705 F.A.C..

The short answer: grease traps are small, under-sink units designed for low-volume operations, while grease interceptors are large, underground systems built for high-volume commercial kitchens.

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What Is a Grease Trap?

A grease trap (also called a grease recovery device or GRD) is a compact unit typically installed directly under a sink or on a kitchen floor. These units handle smaller volumes of wastewater and rely on gravity separation to capture FOG before it enters the drain line.

Key characteristics of grease traps:

• Size: Typically 20 to 100 gallons capacity
• Flow rate: 10 to 50 gallons per minute (GPM)
• Installation: Under-sink or floor-mounted, inside the kitchen
• Cost: $200 to $1,500 for the unit, $500 to $2,000 installed
• Maintenance frequency: Every 1 to 2 weeks (manual cleaning or professional service)
• Best for: Small cafes, coffee shops, food trucks, bakeries, delis with limited frying

Grease traps must meet PDI (Plumbing & Drainage Institute) standards — specifically PDI-G101 for gravity grease interceptors or PDI-G102 for automatic grease removal devices.

What Is a Grease Interceptor?

A grease interceptor is a large, underground tank installed outside the building, typically in the parking lot or service area. These units handle high-volume wastewater flows and require professional pumping service on a regular schedule.

Key characteristics of grease interceptors:

• Size: 500 to 2,000+ gallons capacity
• Flow rate: 50 to 200+ GPM
• Installation: Underground, outside the building — requires excavation
• Cost: $3,000 to $10,000 for the unit, $5,000 to $25,000 installed (including excavation)
• Maintenance frequency: Every 30 to 90 days (professional pump-out required)
• Best for: Full-service restaurants, hotels, hospitals, school cafeterias, catering kitchens

Underground interceptors must meet ASME A112.14.3 (American Society of Mechanical Engineers) or IAPMO Z1001 standards.

Side-by-Side Comparison

Which One Does Your Florida Establishment Need?

Florida building codes and local FOG ordinances determine which system you need. The primary factors are:

1. Your fixture load and flow rate: A plumber or engineer calculates the total GPM from all connected fixtures (sinks, dishwashers, floor drains). This determines minimum trap/interceptor size.

2. Your menu type: Heavy frying operations (fried chicken, fish and chips, Chinese restaurants) produce far more FOG than sandwich shops or coffee shops.

3. Your county's FOG ordinance: Many Florida counties — including Miami-Dade, Pinellas, and Hillsborough — have specific requirements that may exceed state minimums. Some counties mandate underground interceptors for any establishment with a commercial kitchen.

4. Your building type: New construction typically requires an underground interceptor. Existing buildings retrofitting for food service may qualify for an interior grease trap if the flow rate is low enough.

General rules of thumb in Florida:

• Under 50 GPM with limited frying → Interior grease trap may be sufficient
• Over 50 GPM or heavy frying menu → Underground grease interceptor required
• New construction with commercial kitchen → Underground interceptor almost always required
• Food trucks → Portable grease trap (typically 20–40 gallon)

Florida Building Code Requirements

The Florida Building Code (FBC), based on the International Plumbing Code, requires grease interceptors for commercial food service establishments. Key provisions include:

• All food service establishments must have a grease removal system
• Interceptor sizing must follow approved engineering standards (PDI or ASME)
• Local authorities having jurisdiction (AHJ) may impose stricter requirements
• Under Chapter 62-705, all grease waste must be hauled by DEP-licensed transporters regardless of trap or interceptor type

Maintenance Differences

The maintenance approach differs significantly between the two systems:

Grease trap maintenance:

• Can often be cleaned by trained kitchen staff (depending on local regulations)
• Involves removing the lid, skimming accumulated grease, and scrubbing internal baffles
• Some jurisdictions require professional service even for small traps
• See our maintenance tips guide for between-service best practices

Grease interceptor maintenance:

• Always requires professional pump-out service with a vacuum truck
• Hauler must provide a grease waste manifest per Chapter 62-705
• Hauler must be DEP-licensed
• Never attempt to pump an underground interceptor yourself — this violates state regulations

Find a licensed grease trap service company in your area for professional maintenance.

Cost Considerations

When budgeting, consider the total cost of ownership over 5 years:

• Small grease trap: $500 install + $3,000/year maintenance = ~$15,500 over 5 years
• Large interceptor: $15,000 install + $4,000/year maintenance = ~$35,000 over 5 years

The interceptor costs more, but for high-volume operations, it's the only option that keeps you compliant and prevents costly sewer backups. A single grease-related sewer backup can cost $5,000 to $20,000 in cleanup, fines, and lost business.

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Frequently Asked Questions

Can I use a grease trap instead of an interceptor to save money? Only if your flow rate and local code allow it. Installing an undersized grease trap in a high-volume kitchen will lead to overflows, sewer backups, and FOG inspection failures. Your local building department or a licensed plumber can confirm what your establishment requires.

Do I need both a grease trap and an interceptor? In some cases, yes. Large operations may install a point-of-use grease trap at each fixture plus a main underground interceptor. This provides layered protection and is sometimes required by county FOG programs.

How do I know when my grease trap or interceptor is full? The industry standard "25% rule" applies: when FOG and solids occupy 25% or more of the unit's capacity, it needs service. Signs include slow drains, bad odors, and grease visible in the unit. Regular inspections prevent surprises — see our sizing guide for more details.

Does Chapter 62-705 apply to both traps and interceptors? Yes. Chapter 62-705 F.A.C. governs the removal and disposal of grease waste regardless of the source. Whether your waste comes from a small under-sink trap or a 2,000-gallon underground interceptor, the hauler must be DEP-licensed and must provide a proper waste manifest.