How Grease Traps Work and Why Restaurants Need Them

What a Grease Trap Does

A grease trap is a device that intercepts fats, oils, and grease (FOG) from a commercial kitchen before they enter the drain system. Wastewater from the sinks flows into the trap, where the grease cools and solidifies, floating to the top, while the heavier water and solids settle. The grease-free water then flows out to the sewer or the septic system. The trap holds the grease until it is pumped, which keeps the FOG out of the municipal pipes and the drain field.

All Counties Plumbing, Inc. provides grease trap pumping and maintenance service for restaurants and food service facilities across Miami-Dade and Broward Counties. Our technicians pump the trap, scrape the interior baffle walls, and provide the disposal manifests and the compliance documentation the health inspector and the environmental regulators require. Understanding how the trap works helps a kitchen manager recognize the signs that it needs service.

Why Restaurants and Food Service Facilities Need Them

Commercial kitchens discharge high volumes of FOG every day. Without a grease trap, the FOG enters the drain pipes, where it cools and solidifies, narrowing the pipe diameter and eventually causing a blockage. A blocked kitchen drain can shut down a restaurant during peak hours, which is costly and disruptive. The grease trap is the device that prevents this, by intercepting the FOG before it reaches the pipes.

Municipal FOG regulations require food service facilities to maintain their grease traps, which includes pumping them on a schedule and keeping records of the service. A facility that neglects the trap risks a backup, a code violation, and a fine. The maintenance is the less costly and less disruptive choice, and it keeps the kitchen operational and the facility in compliance.

Indoor Traps vs. Exterior Interceptors

There are two main types of grease trap. An indoor grease trap sits directly under a prep sink and handles a smaller flow rate, typically from a single fixture or a small kitchen. An in-ground grease interceptor is a large concrete or fiberglass vault, often 750 to 2,000 gallons or more, that handles the total culinary waste from the facility. The size and the type depend on the kitchen volume and the municipal requirements.

Both types need pumping, but the interval differs. An indoor trap may need service every few weeks, while an exterior interceptor may need service every one to three months, depending on the kitchen volume. The right interval is based on the FOG load, which is why we assess the facility and recommend a pumping schedule that keeps the trap functioning and the facility in compliance.

Warning Signs a Grease Trap Needs Pumping

Several signs suggest a grease trap needs pumping. The most common is slow drainage in the kitchen sinks, which indicates the trap is reaching capacity. Foul odors from the trap or the drains are another sign, since the accumulated FOG produces gases as it breaks down. A backup into a floor drain or a mop sink is a more severe sign that the trap has reached capacity and the line is clogged.

Under municipal FOG regulations, a grease trap typically must be pumped when the combined layer of grease and solids exceeds 25 percent of the liquid volume. This is the standard that the health inspector checks, and exceeding it is a code violation. The signs above often appear before the trap reaches this level, which is why a regular pumping schedule is the better choice than waiting for the signs.

What Happens When a Trap Is Neglected

When a grease trap is neglected, the FOG hardens in the outgoing pipes, which causes a series of problems.

• Severe kitchen sink overflows that can shut down service during peak hours
• Foul kitchen odors that affect the dining area and the staff
• Costly emergency shutdowns to clear a blockage that a scheduled pumping would have prevented
• Municipal code enforcement citations and fines for non-compliance
• Damage to the drain pipes from the hardened FOG, which can require a hydro jetting to clear
• A backup into the municipal sewer, which can affect the facility and the surrounding area

What a Kitchen Manager Can Safely Observe

A kitchen manager does not need to diagnose the problem, but a few safe observations help us understand the situation. Note whether the slow drainage is isolated to one sink or spread across the kitchen. Notice any odors and where they are strongest. Check the last pumping date if known, and whether the trap is due for service. For a backup into a floor drain, call right away, since it is an active emergency.

Do not attempt to open an in-ground interceptor lid without the right equipment, since the lids are heavy and the contents are a health hazard. Describing what you see from a safe distance is enough for us to schedule the right service.

When to Call All Counties Plumbing

Call for any sign of a full trap, for a trap that is overdue for pumping, and for any active backup. For a kitchen backup, call right away, since it can shut down service. For a trap that is overdue, a scheduled pumping prevents the emergency that follows neglect.

All Counties Plumbing serves restaurants and food service facilities across our confirmed Miami-Dade and Broward territory. Call (305) 303-0920 or submit a service request through our contact page to schedule a grease trap service.