Technical Guide
Grease trap sizing is a planning problem before it is an equipment problem. Seats, takeout meals, menu, utensils, fixtures, pump frequency, available space, and jurisdictional review all shape the answer.
How To Think About Size
The Genesis calculator asks for seats, turns per seat, takeout meals, food or establishment type, utensil type, and pump frequency. Those inputs help estimate the grease load between pump-outs. The tool then compares the calculated load to listed model capacity and displays a preliminary recommendation.
That is only the beginning. A final design may depend on fixture schedules, plumbing layout, invert elevations, local code, manufacturer requirements, Authority Having Jurisdiction review, available space, traffic rating, service access, and whether one interceptor or multiple devices are appropriate. This page supports the calculator, not a replacement for engineering review.
Calculator Demonstration
This video walks through a commercial restaurant example and shows how seating, takeout meals, food-service characteristics, FOG generation, pump frequency, grease capacity, and flow rate connect to a preliminary recommendation.
Sizing Questions
A useful sizing discussion starts with the operation, then layers in meals, takeout volume, FOG characteristics, utensils, pump-out frequency, fixture demand, flow rate, space, and local review requirements.
Seat count can miss fast turns, takeout-heavy kitchens, catering, dishwashing, menu changes, and future expansion. Two restaurants with the same seats can create very different grease loads.
A coffee shop, sushi counter, full-service restaurant, fried-food kitchen, bakery, and hotel kitchen can each produce different FOG patterns. The calculator uses food-service categories to keep that assumption visible.
Less frequent pump-outs generally require more storage capacity between service visits. Maintenance planning should be part of the sizing conversation, not an afterthought.
Capacity addresses grease storage. Flow rate addresses wastewater movement through the device. A final equipment selection may need both numbers reviewed with the fixture layout and manufacturer information.
A prior tenant may have had a different menu, lower volume, fewer fixtures, or older approval conditions. Before signing a lease or buying equipment, review whether the existing interceptor matches the new operation.
Use the Tool
Use the actual calculator when you need a preliminary estimate, then move to Genesis review when the result affects a lease, permit, equipment purchase, replacement decision, or installation budget.
Key Concepts
Food service type matters because a sushi counter, coffee shop, full-service restaurant, fried chicken kitchen, and steak-and-seafood restaurant can have different grease characteristics.
Seating capacity alone can be misleading. Turns per seat and takeout meals can change the estimated daily load.
Capacity relates to how much grease the unit can hold between pump-outs. Pump frequency affects how much accumulation the system must tolerate.
Flow rating is a separate equipment issue from grease storage. It can matter when fixtures, dishwashing, or simultaneous discharge are reviewed.
A theoretically correct unit can become a bad operational choice if pump access, covers, risers, or traffic conditions make maintenance difficult.
Local authorities, designers, manufacturers, and inspectors may require information that goes beyond a web calculator.
Before You Choose A Model
Input Quality
Owners should avoid entering the smallest possible version of the business just to obtain a smaller result. A practical sizing discussion should reflect the likely menu, seating turnover, takeout volume, utensil type, pump frequency, and fixture demand. If the restaurant may expand hours, add a dish machine, change from coffee service to cooking, or add catering, those plans should be disclosed before the project team relies on a preliminary recommendation.
Capacity and flow rate should also be kept separate in the conversation. Grease capacity relates to storage between pump-outs, while flow rate relates to how wastewater moves through the device. A field review can reveal constraints that a calculator cannot see, including pipe elevations, tank depth, service access, traffic loading, and whether multiple interceptors or a different configuration should be reviewed by the design team.
Primary Tool
The calculator organizes your food-service assumptions into a preliminary report you can share with Genesis for review.