What backflow protection does restaurant equipment need under Maricopa County plan review?

Under Potable Water Backflow Protection, the guide gives these equipment rules:

• Carbonators. "Provide an approved reduced-pressure backflow preventer or another approved, testable, continuous-pressure backflow device." It goes between the water supply line and the carbonator. The relief valve needs an approved funnel drain assembly with an air gap plumbed to a floor sink, water filters go on the supply side of the preventer, and the preventer must be certified, with a copy of the test certification provided.
• A lower minimum for carbonators. "An ASSE 1022 or approved device is the minimum level of protection required for carbonator systems." The guide notes these devices are not testable, so when one is the only protection, "a written maintenance policy must be in place that requires the annual inspection of these devices." It also says an approved testable reduced-pressure preventer is "highly recommended."
• Other beverage machines. The water supply to non-carbonated beverage dispensers must be protected by a backflow preventer conforming to ASSE 1022, or by an approved air gap (IPC 608.17.1.2).
• Submerged inlets. "Provide approved vacuum breakers on submerged water inlets such as ware washing machines, wok cook table, garbage grinders and any threaded water outlets." An atmospheric vacuum breaker goes at least 6 inches above the highest outlet and cannot have a valve downstream (IPC 609.4).
• Plain inlets. A faucet inlet needs an air gap of at least twice the diameter of the inlet. A faucet that can take a hose "may be considered a submerged inlet."
• Hard-to-vent cases. Where an atmospheric vacuum breaker cannot go after the last shut-off valve or solenoid (the guide's example is pressure spray hoses), use a double check with atmospheric vents, a pressure vacuum breaker or a reduced pressure preventer (IPC 608.16.4).
• Everything else. All equipment and fixtures connected to a water supply need an approved backflow device or air gap, and the preventer must be certified with the test copy provided.

For reverse osmosis, the guide is stricter: "An approved, testable high-hazard continuous pressure backflow preventer must be provided immediately upstream from any RO system (e.g., RPZ backflow preventer)."

• Submerged inlet. A water inlet without the required air gap above the fixture it feeds. The guide says such an inlet needs approved backflow protection.
• Testable. The guide asks for testable devices on carbonators and RO systems and says ASSE 1022 devices are not testable. It does not define the word further.
• Continuous pressure. The guide uses this term for the preventers it requires on carbonators and RO systems. It does not define it.

Restaurants and other food establishments whose plans are reviewed under the Maricopa County guide. The rules in this section of the guide are written for equipment and fixtures. The guide adds: "Check with your local building department or local plumbing backflow/cross-connection specialist for current requirements. They may have more stringent regulations."

This does not apply as written if your food establishment is in Pinal County. Pinal has its own packet, with a shorter rule.

A new soda station. The designer draws an RPZ ahead of the carbonator with the relief outlet air-gapped to a floor sink, stainless or flexible line downstream, and the filter on the supply side. The reviewer finds every item on the guide's list and approves it.

A minimum-protection submittal. The owner proposes only an ASSE 1022 device on the carbonator. The guide calls that the minimum, and adds the written annual inspection policy for when it is the only protection, so the submittal should include that policy.

The edge case. An RO system is added to the ice machine supply. The guide wants a testable high-hazard preventer immediately upstream of any RO system, and it bars copper or copper alloy downstream of the RPZ or the RO system. A line run in copper by habit fails that check.

1. 1List every piece of equipment tied to a water line and note its inlet type: air gap, submerged or hose-threaded.
2. 2Match each item to the table and show the device on the plumbing schedule, since backflow prevention devices are a required schedule item.
3. 3Keep copper and brass out of downstream runs from carbonator and RO devices.
4. 4Have each testable preventer tested and certified. The guide says to "provide a copy of the certification for the backflow preventer test" and does not state a date or office for it, so ask the reviewer when it is wanted. Pinal County asks for the testing results before final approval.
5. 5Submit the plan set through the Maricopa County Permit Center. The guide's Plan Review Steps say to complete the Plan Review Application, provide the supporting documents and pay the application fees there, and the Permit Center page says "All new permit and plan applications will be submitted through Permit Center."
6. 6Pay the plan review fee on the county fee schedule: $728 for an eating and drinking establishment with 0-9 seats, $885 for 10 or more (MCEHC Chapter I Fee Schedule, Rev 08/19/2026, page 28). Expedited plan reviews are assessed at two times the flat fee.
7. 7Apply at least 6 to 8 weeks before construction starts, which is the guide's recommendation. "Construction shall not commence unless the required plans have been approved." The submittal list is on the plan approval page.
8. 8HQ Plumbing & Air tests, repairs and replaces domestic backflow assemblies, such as the ones on soda and RO lines. Fire sprinkler backflow is a separate trade.

• Myth: The backflow device at the meter covers the equipment. The guide asks for protection at each piece of equipment, based on its hazard level.
• Myth: ASSE 1022 is a testable assembly. The guide says these devices are not testable.
• Myth: RO water is just filtered water. The guide treats RO as needing a high-hazard preventer upstream and bars copper or copper alloy downstream.
• Myth: A valve after the vacuum breaker is fine. The guide says an atmospheric vacuum breaker cannot have a valve downstream.