Grease Trap Requirements
Stockton, CA

FOG Compliance in Stockton, CA

Food service establishments in Stockton operate under a combination of federal EPA pretreatment standards, California state plumbing code, and city-level FOG ordinances. Together these rules determine how grease traps must be sized, how often they must be pumped, and what happens when a restaurant falls out of compliance.

Pumping frequency is the compliance rule restaurant owners interact with most often. In Stockton, the rule is: Every 3 months or when combined FOG and solids reach 25% of design hydraulic depth, whichever comes first. This aligns with the 90-day US median enforced by most major cities. The city follows the Uniform Plumbing Code (UPC) for trap sizing and installation. Under Section 1014, which applies a fixture drainage load formula with a retention time factor, grease interceptors installed in Stockton must meet minimum capacity thresholds based on the fixtures connected to them — 3-compartment sinks, dishwashers, pre-rinse stations, wok stoves, and floor drains on the cook line. The local minimum trap size is: Per California Plumbing Code; minimum two compartments required. Access manholes minimum 24-inch diameter over each chamber..

Stockton requires a dedicated FOG permit for any food service establishment generating fats, oils, and grease. The permit is separate from, and in addition to, the plumbing permit required at installation. Violations carry maximum penalties of Violations are misdemeanors per SMC 1.08.010; administrative civil penalties per Title 1 . Fines typically escalate with repeat violations, and severe discharges that cause sanitary sewer overflows can trigger federal Clean Water Act penalties layered on top of local fines.

Stockton enforces the 25 percent rule: grease traps must be pumped before the combined FOG and settled solids reach 25 percent of the trap's total liquid depth. Inspectors measure the depth with a sludge judge or dipstick, typically at surprise visits. Exceeding the threshold at inspection triggers a notice of violation and mandatory emergency pump-out, regardless of the scheduled pumping cycle. Inspections by Director or enforcement officer; documentation must be available on request. Establishments must maintain pumping logs, hauler manifests, and inspection reports on-site — missing records is itself a violation in most enforcement actions. Enforcement authority rests with the City of Stockton Municipal Utilities Department, which handles permit issuance, inspections, and hauler licensing.

For a deeper explanation of the rules this city enforces, read our guides on how grease traps work and the 25/50 pumping rule.