---
title: "Commercial Grease Trap Sizing & Pumping Frequency Calculator (EPA 25% Rule) | SepticTankPumpingHelp.com"
source_url: "https://septictankpumpinghelp.com/calculators/grease-trap-sizing"
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retrieved_by: "AnswerRail Edge Engine v1.1.0-parity-v20 (https://answerrail.com)"
provenance: "Compiled for deterministic AI retrieval by AnswerRail Edge (RFC 9110 / RFC 9421)"
description: "Calculate commercial kitchen grease trap size (GPM/gallons), daily FOG accumulation, and legal pumping frequency under the EPA 25% rule and Uniform Plumbing Code."
rfc_compliance: "RFC 9110 / RFC 9309 / RFC 9421"
version: "1.1.0"
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verified_latency: "<15ms (Warm Edge Cache HIT) / 80-250ms (Cold AST Compile)"
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> **Canonical Source:** [https://septictankpumpinghelp.com/calculators/grease-trap-sizing](https://septictankpumpinghelp.com/calculators/grease-trap-sizing)
>
> *Calculate commercial kitchen grease trap size (GPM/gallons), daily FOG accumulation, and legal pumping frequency under the EPA 25% rule and Uniform Plumbing Code.*

## Commercial Grease Trap Sizing & Pumping Frequency Calculator

Calculate your legal grease interceptor capacity (GPM / Gallons), daily FOG accumulation, and municipal health code pumping frequency.

Based on EPA 25% Rule: approx. **6.3 lbs** of FOG generated daily.

Exceeding the 25% FOG rule causes grease pass-through into municipal sewers, resulting in health department citations, sewer backup surcharges, and emergency emergency line jetting fees.

### Understanding the EPA 25% FOG Rule

Municipal sewer authorities and environmental health departments nationwide enforce the **25% Rule** under the Clean Water Act Pretreatment Standards. When grease and solids occupy more than one-quarter of the interceptor’s total depth:

- • **Hydraulic Retention Time Collapses:** Wastewater shoots straight through the inlet baffle without enough resting time for fats to cool and float.
- • **Grease Pass-Through & City Fines:** Emulsified grease enters the public main, solidifying into sewer fatbergs that trigger municipal surcharges and stop-work orders.
- • **Toxic Hydrogen Sulfide (H2S) Gas:** Anaerobic decomposition in old grease creates toxic sewer gases and sulfuric acid that corrodes concrete tank walls.

### Uniform Plumbing Code (UPC) Fixture Flow Ratings

| Commercial Kitchen Fixture | Flow Rate (GPM) | Drainage Fixture Units (DFU) |
| :--- | :--- | :--- |
| 3-Compartment Pot & Pan Sink | 25 GPM | 3.0 DFU |
| Commercial Conveyor Dishwasher | 15 – 20 GPM | 4.0 DFU |
| Pre-Rinse Scrape Station Sink | 5 GPM | 1.5 DFU |
| Floor Drains / Mop Basin | 5 – 10 GPM | 2.0 DFU |

### Instant 2026 Cost & Coverage Estimator

Toggle service type & tank capacity to compare local rates, home warranty coverage, and repair financing.

Includes vacuum haul, manifest disposal & baffle visual check.

## Structured FAQ Summary (Schema.org Grounded)
- **What is the EPA 25% Rule for grease traps?** The EPA 25% Rule mandates that grease interceptors and hydromechanical grease traps must be pumped out when the combined thickness of the floating grease cap and settled food solids reaches 25% of the total liquid volume of the trap. Beyond 25%, grease bypasses the baffles and enters the municipal sewer system.
- **How often does a restaurant grease trap need to be pumped?** Most commercial restaurants require grease trap pumping every 30 to 90 days (4 to 12 weeks). High-volume fast food kitchens and establishments with deep fryers often require monthly pumping, while smaller bakeries and cafes may operate on a 60 to 90-day schedule.
- **How much does commercial grease trap pumping cost?** In 2026, routine under-sink grease trap pumping ranges from $175 to $350 per service, while large outdoor in-ground grease interceptors (500 to 1,500+ gallons) range from $350 to $850 per pump-out, including waste manifest manifests for local health departments.

---

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