Managing Fats, Oils, and Grease in Commercial Food Service Establishments
Fats, oils, and grease (FOG) are routine byproducts of restaurants, cafeterias, hotels, hospitals, schools, food processors, and other commercial kitchens. When they enter a sanitary sewer in liquid form, they can cool, cling to pipe walls, combine with solids, and create restrictions that grow over time. A small discharge from one facility can become a costly operational problem when repeated across an entire service area.
Effective FOG control combines source reduction, proper equipment, regular inspection, employee training, and accurate records. The strongest programs treat grease management as a daily operating practice rather than an occasional response to a sewer backup.
For water and wastewater professionals in the Los Angeles Basin, local conditions, agency requirements, seasonal demand, and the design of each collection system all influence the right approach. Commercial operators can support reliable sewer service by understanding how grease moves through their facility and taking action before an accumulation becomes a blockage.
Why FOG Creates Collection System Problems
FOG enters a kitchen wastewater stream through dishwashing, food preparation, floor cleaning, equipment washing, and the disposal of liquid cooking oil. Hot water may carry grease farther into a building drain, but cooling wastewater allows the material to solidify. Grease can then attach to pipe interiors and trap food particles, paper, and other debris.
The resulting deposits may reduce pipe capacity, cause backups, and contribute to sanitary sewer overflows. In a commercial kitchen, a backup can shut down food preparation, damage property, create health concerns, and lead to emergency plumbing costs. For a wastewater agency, repeated blockages increase inspection, cleaning, regulatory, and public-response expenses.
FOG also affects pumping stations and treatment facilities. Heavy deposits can interfere with pumps, increase maintenance needs, and add avoidable loading to preliminary treatment processes. A preventive program protects both the establishment and the broader wastewater infrastructure.
Find the Highest-Risk Sources
A useful assessment begins with a walk-through of every area where grease or food solids are generated. Common sources include deep fryers, griddles, roasting pans, meat preparation sinks, three-compartment sinks, dishwashers, garbage grinders, and mop sinks. Staff should observe actual work practices instead of relying only on a plumbing diagram.
The assessment should document drain locations, flow paths, grease control devices, cleanouts, access points, and the destination of used cooking oil. It should also identify practices that increase risk, such as rinsing grease into a sink, scraping food waste into a drain, or using excessive detergent to move oil through the plumbing.
Facilities with changing menus or high-volume service may need a fresh evaluation after renovations, equipment additions, or changes in operating hours. A new fryer line or expanded catering operation can alter wastewater characteristics enough to require revised maintenance intervals or additional pretreatment capacity.
Choose and Maintain the Right Controls
Interior grease traps, grease interceptors, automatic grease removal devices, drain screens, and oil collection containers each serve a different purpose. The best setup depends on kitchen flow, fixture connections, available space, local requirements, and the quantity and type of grease produced. Equipment should be correctly sized and installed so wastewater receives adequate retention time.
A grease interceptor cannot compensate for poor source control. Food scraps should be scraped into solid waste or organics containers, and used fryer oil should be collected for recycling or approved disposal. Staff should avoid using hot water, solvents, enzymes, or emulsifying chemicals as a substitute for physical removal unless the responsible authority specifically permits the practice.
| Control measure | Primary purpose | Operating focus |
|---|---|---|
| Drain screens and baskets | Capture food particles near fixtures | Empty and wash frequently |
| Interior grease trap | Remove grease from lower-volume fixtures | Inspect, clean, and record service |
| Exterior grease interceptor | Provide larger-scale separation and retention | Pump before excessive accumulation |
| Used-oil container | Collect recoverable cooking oil | Keep covered, secure, and leak-free |
| Employee procedures | Prevent FOG at the source | Train during onboarding and refresh regularly |
Service intervals should reflect measured accumulation rather than a convenient calendar alone. Many programs use a rule based on the combined thickness of floating grease and settled solids relative to the liquid depth, while local ordinances may establish specific requirements. Inspection records should include dates, condition, accumulated material, service provider, and corrective actions.
Make Daily Operations Part of the Program
Employees are the first line of defense. A short procedure can establish expectations: scrape plates before washing, collect fryer oil in a designated container, keep solids out of floor drains, use sink strainers, and report slow drains immediately. Signs placed near sinks and fryers reinforce these steps during busy shifts.
Cleaning practices require careful coordination. Staff should wipe pans and equipment with absorbent material before washing, collect grease from roasting trays, and avoid directing concentrated grease toward a drain. A cleaning schedule should identify who performs each task, what acceptable conditions look like, and how completion is documented.
Managers should include FOG procedures in new-hire orientation and provide refresher training when inspection results show recurring problems. A simple log can record interceptor checks, trap cleaning, oil pickup, drain observations, and employee coaching. Consistent documentation helps demonstrate due diligence and reveals patterns before they become failures.
Inspect, Measure, and Respond Early
Warning signs include slow drainage, recurring odors, gurgling fixtures, grease around access covers, frequent plumbing service calls, and unusually rapid interceptor accumulation. These conditions should trigger investigation rather than repeated use of drain chemicals. The goal is to locate the source, correct the behavior or equipment issue, and verify that the remedy works.
Inspections should cover both the kitchen and the outside interceptor. Authorized personnel can check baffles, covers, inlet and outlet conditions, structural integrity, and evidence of bypassing. The facility should maintain clear access to covers and avoid placing storage, vehicles, or waste containers over inspection points.
A written response plan makes urgent events easier to manage. It should identify internal contacts, the wastewater agency or sewer authority, plumbing and pumping contractors, spill-control materials, and steps for protecting nearby drains. Any discharge to soil, storm drains, or surface waters requires prompt escalation under applicable local and state requirements.
Connect FOG Control With Wider Water Stewardship
Grease management fits within a larger responsibility to protect collection systems, treatment processes, and beneficial end uses of water resources. Wastewater agencies and professionals also address biosolids quality, residuals management, source control, and regulatory compliance. Teams reviewing treatment and disposal practices can use this California biosolids refresher to keep related requirements in view.
Commercial operators benefit from communicating with their local sewer authority before installing, modifying, or abandoning grease control equipment. Early coordination can clarify permit expectations, inspection procedures, pumping documentation, and prohibited practices. It can also prevent an expensive installation that fails to match the facility’s wastewater profile.
Professional networks provide another practical resource. Engineers, operators, consultants, and agency staff can exchange lessons from inspections, maintenance programs, and enforcement cases through the LABS of CWEA committee, along with technical presentations, workshops, and facility-focused learning opportunities.
Priorities for a Stronger Program
A focused improvement plan helps a busy food service operation move from reactive maintenance to reliable prevention.
- Map every grease-producing fixture and confirm where each drain discharges.
- Establish written procedures for scraping, oil collection, sink use, and spill response.
- Set inspection and pumping intervals using actual accumulation data and local requirements.
- Train every employee who handles food, dishes, equipment, or floor cleaning.
- Review service records and sewer-related incidents monthly for recurring patterns.
Put Prevention Into Practice
Successful FOG management is visible in ordinary details: a clean drain screen, a covered oil container, an accessible interceptor, a completed service log, and an employee who knows where grease belongs. These actions protect a restaurant’s operations while reducing preventable demands on the public sewer system.
Water and wastewater professionals can strengthen results by sharing clear expectations with food service owners, conducting practical inspections, and connecting regulatory requirements to daily operating decisions. Commercial establishments can begin with a kitchen walk-through, correct the highest-risk practice, and build a maintenance record that supports continuous improvement.
Use the resources and professional connections available through LABS of CWEA to deepen technical knowledge, exchange field experience, and promote dependable wastewater practices across the Los Angeles Basin.