Which equipment needs its own backflow device in Mesa? City Code 8-1-9 point-of-use rules

Every piece of equipment connected to a customer water system is "subject to evaluation for cross-connection potential and the degree of hazard." The customer must install and maintain point-of-use protection at each connection, have the assembly tested annually and make sure reports reach the Department. Four installation rules follow:

• Height and access (B). Install no more than five feet above finished floor, accessible for testing. Removing an access panel or door is allowed.
• No copper downstream (C) of a point-of-use assembly where the water is carbonated, deionized, distilled or treated by reverse osmosis.
• RPA drains (D). A point-of-use RPA needs an air-gapped drain line for its relief valve, at least as large as the RPA, properly secured and routed to a floor sink, mop sink or other appropriate wastewater outlet. Flexible hose is not permitted.
• One device, one use (E). Multiple uses downstream of one point-of-use device are prohibited unless the Department approves. It may approve one assembly for a group of similar items, such as pedicure stations.

Subsection (E) also holds the equipment list. A sample:

• Point of use. The equipment connection itself, downstream of the meter.
• AG, AVB, PVB, SVB. Air gap, atmospheric vacuum breaker, pressure vacuum breaker and spill-resistant vacuum breaker. Lighter devices for lower hazards.
• RPA, DCVA. Reduced pressure and double check assemblies. See which uses need an assembly.
• Dual check. Defined in 8-1-1 as two independent check valves with an atmospheric vent, for non-health or low hazard uses only. Those non-testable devices "can only be installed on ice makers and non-carbonated beverage dispensers."

Any Mesa customer with listed equipment: restaurants, coffee shops, dental and medical suites, salons, car washes, labs, pools and boiler rooms. Equipment that does not appear on the list can still be evaluated based on the degree of hazard.

A coffee shop. The soda dispenser needs an RPA because the water is carbonated, and the line downstream cannot be copper. The ice maker takes a lighter device.

A dental suite. Each chair has an RPA, its relief drain runs air gapped to a floor sink, and the devices are within five feet of the floor so the tester can reach them.

The edge case. A nail salon installs six pedicure chairs on one device without asking. The section prohibits multiple uses downstream unless approved, so the group approval has to come first.

1. 1List every piece of water-using equipment and match it to the 8-1-9 table.
2. 2Show the devices on the plumbing plans. See backflow on plans.
3. 3Set each device within five feet of the floor, with access and an air-gapped drain for any RPA.
4. 4Keep copper out of the line after carbonated, RO, distilled or deionized water.
5. 5Add each device to the annual test schedule.

• "The meter device covers everything inside." Point-of-use devices are on top of it.
• "A hose is fine for the RPA drain." Flexible hose is not allowed.
• "The list only applies to restaurants." It covers labs, salons, car washes, mortuaries and more.
• "One device can serve any group of equipment." Only with Department approval, and only for similar items.