Kitchen Code Pro

Grease Trap Rules for Mobile, AL Restaurants: The Short Version

Every food service facility in Mobile that puts fats, oils, and grease down a drain is regulated by the Mobile Area Water and Sewer System (MAWSS) under its Grease Control Program. The program dates to a 2002 consent decree with the EPA and the Alabama Department of Environmental Management, and it comes with real teeth: inspections, fines on your water bill, and in the worst case, loss of water and sewer service.

The requirements below come from two MAWSS documents: the Food Service Facility Grease Control Manual and the Policy and Procedure Manual. Both are worth keeping on file, and requirements can change, so confirm current details with the MAWSS Pretreatment Department at (251) 378-3514.

The 25% rule, straight from the manual

Your grease trap must be pumped before the floating grease layer plus the settled solids reach 25% of the trap’s total liquid depth. MAWSS’s inspection checklist states it plainly: all traps must meet the 25% rule, and the fine is $400 for each trap in violation, billed to your water account.

There is no calendar schedule in the manual. The trap’s condition decides. In practice a busy commercial kitchen fills a trap to the 25% line in roughly 1 to 3 months, but that is operating experience, not a MAWSS number.

You are also required to check the trap yourself between pumpings. The manual includes a standard procedure using a clear dipstick tube to measure the grease layer and settled solids, and a Grease Trap Inspection Checklist that must be kept on file at the facility. MAWSS does not install, service, or maintain grease traps; that responsibility is entirely yours.

Board-designated haulers and the manifest

Two rules from the manual that surprise many operators:

  1. All grease pumped from your trap must go to the MAWSS Public Grease Treatment Facility.
  2. You must use only Board-designated grease hauler contractors to pump and transport it.

Every pumping generates a three-part Grease Disposal Manifest. You fill out the top, the hauler completes the transport section, the disposal facility completes the bottom, and the original comes back to you. Tracking that manifest is your responsibility, and the completed original must be on site and available when a MAWSS inspector asks for it. The manual does not state how many years to keep old manifests, so keep them indefinitely; the paper trail is your proof.

Fees, inspections, and sampling

Each food service facility pays a monthly Grease Control fee. Per the MAWSS fee schedule: $20 per month if your trap is sized as recommended, or $50 per month plus sampling if it is smaller than recommended, along with a $75 annual administrative fee.

MAWSS inspects quarterly and can sample your discharge at random from a required sampling port. The discharge limit is 100 mg/L of fats, oils, and grease. A single sample over 200 mg/L draws a $200 fine. Three samples over 500 mg/L, or a 12-month average over 140 mg/L, triggers a mandatory new Action Plan for your grease control setup. Discharges over the 100 mg/L limit can also draw a surcharge of $0.25 per pound. Unpaid penalties result in loss of water and sewer service.

Trap sizing

MAWSS sizes traps with a formula based on seats, table turnover, dishwashing equipment, kitchen type, and operating hours, with a minimum of 500 gallons. If your trap is undersized, you have 90 days from MAWSS’s initial training visit to submit an Action Plan choosing one of four fixes: replace the trap, add traps in series, install an approved alternative device, or prove compliance through operational changes and additives. Miss the deadline and MAWSS is obligated to discontinue water and sewer service.

Trap vs. interceptor, quickly

A grease trap is the smaller unit, often under a sink indoors. A grease interceptor is the large in-ground tank outside, used by higher-volume kitchens. MAWSS’s Policy and Procedure Manual requires interceptors wherever the Director deems them necessary for handling grease-laden wastewater, and the owner must inspect, clean, and repair them regularly at the owner’s expense. Home remedies like hot water flushes do not replace pumping, and the pollutant rules prohibit discharging anything over 110 degrees F to the sewer, so flushing with boiling water can itself be a violation.

Keep the file current

At inspection, MAWSS expects to see your initial training checklist, your self-inspection records, completed manifests, and prior quarterly inspection checklists. Employees are also required to complete grease handling training through the Mobile County Health Department.

Pair it with your hood schedule

The same kitchens that fill a grease trap fast usually need frequent hood cleaning under NFPA 96. Many Mobile operators put both on one compliance calendar so nothing slips. See our hood cleaning frequency guide, then compare licensed grease trap services in Mobile in our directory.