Use the approved commissary or another disposal arrangement approved by Maricopa County. Wastewater holding tanks must empty into an approved sewage disposal system, and grease must be disposed of in a sanitary manner. A random cleanout, storm drain or landscape area is not an approved disposal site. Follow the approval for your unit.
What the county's code says
Three lines from the mobile food rules carry the answer:
- Mobile food establishments "shall operate from an approved commissary or other food service establishment" and report at least daily for supplies, food storage, vehicle and equipment cleaning, waste disposal and service operations.
- "All wastewater and grease shall be disposed of in a sanitary manner."
- "Wastewater holding tanks shall be emptied into an approved sewage disposal system."
The code also says mobile units shall not connect to water or wastewater systems "except during servicing operations at a commissary or as approved by the Department." So a sewer cleanout behind a shopping center, a storm drain or a landscape bed isn't an approved option. If a spot isn't your commissary or something the county approved, don't dump there.
Mesa's city guide for restaurants makes the same point about washing equipment outdoors: don't do it where grease and food waste will flow into storm drains or dry wells.
What a commissary provides
The county's commissary page lists what a commissary can offer: fresh water, food prep, chemical storage, gray water disposal, trash disposal, ware washing and food storage. The commissary rules add a duty. A commissary must provide for sanitary disposal of liquid waste, and for handling and disposal of garbage, grease and rubbish from mobile units.
Each unit needs a signed commissary agreement at initial permitting and at renewal. The county verifies that the facility can deliver the services your truck needs. Trucks serving time and temperature controlled foods also keep a log of commissary visits with the unit. The code has that log kept for 30 days, available for county review.
How the truck itself is built for this
For a Type III unit (an enclosed truck that prepares, cooks, holds and serves food), the county's plan review list asks for:
- A wastewater tank 15 percent larger than the fresh water tank.
- A wastewater drain valve larger than 1 inch, with the drain at the lowest point of the tank, so the water runs out when the valve opens.
- Quick-disconnect sewer and potable water connections.
- Plumbing connections that are all different sizes.
The code adds that the holding tank drains to a valve at least 1 inch in inner diameter. That's the hookup you use at the commissary dump station.
What if my commissary isn't on the county list?
The list isn't all-inclusive. The county says other facilities may be approved if their services meet the truck's needs. The catch is the three-compartment sink. If your unit has one and you use a commissary that isn't listed, you need written approval from the local jurisdiction where that fixed food establishment is. The county points you to that city's pretreatment program. So a restaurant that lets your truck dump into its drain needs its city's sign-off, not just a handshake.
What this means for a restaurant or kitchen that hosts trucks
If you run a commissary kitchen or let a truck use your facility, the wastewater ends up in your plumbing and possibly in your grease control device. Plan for that load when sizing an interceptor, and keep pumping records for the device. HQ does commercial plumbing for commercial kitchens, including floor sinks, drains and hookups, and we give free estimates. For the other side of the same rules, see what can go down a restaurant grease trap.