Determine the flow rate of your sink:

### If Draining Multiple Sinks Into One Grease Trap

**Calculate the capacity of the sink in cubic inches (measurements of one compartment), and multiply that total by the number of compartments:**

**Convert the capacity from Total cubic inches to gallons per minute (GPM):**

**Adjust for displacement (displacement takes into consideration the actual useable capacity of your sink):**

* The resulting GPM is the required flow rate to drain the sink in one minute. You would then choose a grease trap with a GPM flow rate close to this number.

- Determine the flow rate for each sink to be serviced by the grease trap using the same calculations as a single sink.
- Add together 100% of the largest flow rate, 50% of the second largest, and 25% of all others.
- The result is the recommended flow rate (in GPM) of the grease trap.