Grease Trap Requirements for a Commercial Kitchen

A commercial kitchen needs a grease trap, or a grease interceptor, on every drain that carries greasy water. The International Plumbing Code, which many states and cities adopt, lists the usual ones: pot sinks, prerinse sinks, soup kettles, wok stations, floor drains or sinks that kettles drain into, hood wash units, and dishwashers without a prerinse sink. The same code says a food waste disposer can't drain into a grease interceptor, restricts what additives can be dosed into one, and sizes them to ASME or PDI standards. The FDA Food Code adds one line: a grease trap has to be easy to reach for cleaning. Pumping is where the city comes in. Sewer utilities can't accept grease that blocks their pipes, under the federal pretreatment rule, so many run a fats, oils and grease (FOG) program with its own permit, pumping schedule and records. A missed pump-out is a common cause of a backed-up floor drain and a fine. In the example below, a shared kitchen sets up a pump-out log after a city inspection.

The short version

• A grease trap or interceptor receives every drain with greasy water.
• The plumbing code lists pot sinks, prerinse sinks, kettles, wok stations, kettle floor drains, hood washes and some dishwashers.
• No garbage disposer into a grease interceptor.
• Sized to ASME or PDI standards by your plumber or engineer.
• The Food Code: easy to reach for cleaning.
• Your city's FOG program sets the permit, how often it's pumped and the records.
• Keep a log of each check and pump-out, with the hauler's manifest.
• TaroStack keeps your own fields on records, for checks done with the day's work. More below.

Which fixtures drain to it

The sinks themselves are in three-compartment sink requirements and commercial kitchen sink requirements.

The rules

Your city adopts its own edition of the plumbing code and runs its own FOG program; its pumping rule is the one that counts. This is general information, not legal advice.

An example: a shared kitchen's pump-out log

Shenandoah Commons Kitchen, a made-up shared kitchen in Harrisonburg, Virginia, has about 30 members and an underground 1,000-gallon grease interceptor serving its pot sinks, prerinse sink and kettle floor drains. A city FOG inspector found no pumping records for the past year. Say its city's program asks for pumping at least every 90 days, or sooner when the grease and solids reach a quarter of the tank's depth, with the hauler's manifest kept on site; those numbers are an example, so check your own city's. The new log:

The August reading passed a quarter of the depth three weeks before the 90 days were up, during the busiest catering month, so the kitchen checks every four weeks now and more often in the fall. A sign over the pot sinks asks members to scrape plates into the bin first. The kitchen's own rules for members are in shared kitchen rules.

Get the log

Download the grease interceptor pump-out log. One sheet: type your city's pumping interval and the share of depth that triggers a pump-out, then each check's date, the grease and solids depth and the tank's depth; the share, whether it's time to pump and the next check due fill in, with the hauler, gallons and manifest number for each pump-out. It's an ordinary Excel file with no macros, and it works in Google Sheets, LibreOffice and Numbers.

Where this stops working

The log covers the interceptor. An inspector reading it also wants the kitchen's cleaning records and which member was using the kettles the week the drain backed up.

How TaroStack does it

TaroStack doesn't track grease interceptors. It keeps the kitchen's own records with the work they belong to.

Your own fields on records. Fields of your own on batch records, receipts and counts can hold a check, such as "pot sink drain clear", with initials, filled in on a phone.

Members' goods as their own. A shared kitchen can keep each member's goods as the member's own, received, counted and released, so the walk-in shows whose food is whose.

Printable records. Batch-record forms print with your own checklist fields and a sign-off, for the binder an inspector reads.

Your own fields and printable records are on every plan, from $49 a month; keeping members' goods is on Standard, at $99 a month. The first 30 days are free, with no credit card. If you'd like a hand setting up, ask, and we'll do it with you.

Questions people also ask

Do I need a grease trap for my commercial kitchen?

Yes, for any drain carrying greasy water: the plumbing code lists pot sinks, prerinse sinks, kettles, wok stations, hood washes and some dishwashers.

How often should a grease trap be cleaned?

As often as your city's FOG program requires, and sooner when grease and solids build up faster; check whether your city sets a time limit, a fill level or both.

Can a garbage disposal drain into a grease trap?

No. The plumbing code says a food waste disposer can't discharge to a grease interceptor.

What is the difference between a grease trap and a grease interceptor?

Both separate grease from wastewater; a grease trap is usually a small unit near the sink, an interceptor a larger tank, often underground.