The rule, in one sentence
City code caps fat, oil and grease in your wastewater at 100 parts per million and gives the Department of Public Utilities the power to inspect at any time, prescribe your equipment, bill you for treatment, and discontinue service for violations (Sec. 28-907). There is no “every 90 days” in Richmond’s code. That is less convenient than a calendar, and stricter: a full trap is out of compliance the day it fills, not the day a schedule expires.
Turning a number into a calendar
Separation only works while there is water volume for grease to separate in. Industry practice plans a pump-out at about 25% accumulation of grease and solids — well before efficiency collapses. Richmond’s Department of Public Utilities says the same in its own food-service bulletin: “The City of Richmond Pretreatment Program follows the ‘25% Rule.’ Grease control devices (GCD) fail to efficiently remove FOG once accumulation of floatable FOG material and settled solids total 25% of the total liquid depth of the GCD,” and that owners and managers “are responsible for making the determination of their GCD cleaning frequency based on the 25% Rule” (DPU FSE bulletin, c. 2019). The department’s pretreatment page adds that “many businesses opt to service interceptors every three months.” So the rule is in the program, not the ordinance, and the interval is: how long your kitchen takes to put 25% of the trap’s volume in as grease and solids. That depends on three things you know: trap size, covers per day, and how heavy the menu runs.
| Kitchen | Typical unit | Typical interval |
|---|---|---|
| Cafe, bakery, sandwich shop | 20–40 gal indoor trap | 3–6 weeks |
| Full-service restaurant, fryers | 50–100 gal trap or 500+ gal interceptor | 2–4 weeks (trap) / 60–90 days (interceptor) |
| High-volume, BBQ, fried-chicken | 1,000–1,500 gal interceptor | 30–60 days |
| Brewery with a kitchen | 500–1,000 gal interceptor | 60–90 days — check for spent-grain fouling |
Rows are starting points. The calculator computes yours from your numbers; the first pump-out calibrates it against what actually comes out.
Two ways kitchens get this wrong
Copying the neighbor. A 40-gallon trap behind a fryer line needs a different interval from the same trap behind a salad bar. Trusting the skim. A vendor who removes only the cap leaves the solids that fill the trap from the bottom. The interval you set means nothing if each service only resets the top layer. Insist on full evacuation and a receipt that says gallons removed.
Set the interval once
Trap size, covers, menu. We will put you on the schedule your arithmetic says.
Call (804) 234-8623