Glendale City Code 33-90: which businesses need a backflow device

Section 33-90(a) says that when any listed activity happens on premises served by the public water system, "a potential hazard to the public potable water supply shall be presumed and a backflow prevention device, of the type specified for that activity herein, must be utilized or installed at the service connection for that service address." Put simply, the list decides the device, and the device goes at the service connection, not at each fixture.

The list sorts into two groups:

• Reduced pressure (RP) assembly: aircraft and missile plants, animal clinics and grooming shops, automotive repair with steam cleaners, acid or solvent equipment, breweries, bottling plants, car washes, commercial laundries, chemical and plating plants, hospitals and mortuaries, medical and dental buildings, schools and colleges, hotels, motels and resorts, restaurants and bakeries, multi-family, mobile home parks, buildings with sewage ejectors, buildings over three stories or 34 feet from curb level, and any premises with a cross-connection.
• Double check (DC) assembly: buildings with house pumps or potable storage tanks, dairies and cold storage plants, and shopping centers.
• RP or air gap: buildings with landscape fountains, ponds or baptismal tanks, street sweepers, water trucks and hydraulic sewer cleaning equipment.

Fire systems have their own lines. AWWA classes 1, 2 and 3 need a DC, and so does any system 6 inches or larger or built of piping not approved for potable use. Classes 4, 5 and 6 need an RP. Irrigation systems other than single-family homes need an RP where they have elevated or drip systems or non-potable piping 2 inches or smaller.

When more than one activity shares a service, subsection (b) says the most restrictive device wins: air gap, then RP, then pressure vacuum breaker, then DC.

• Service connection: where the city's water line meets your property, normally at the meter. The device goes there.
• RP and DC: an RP has two check valves and a relief valve between them. A DC has two check valves and no relief valve. The RP protects against more serious hazards, which is why the list gives it to most uses.
• Presumed hazard: the code assumes danger for anything on the list. You do not have to prove contamination is likely.

It covers businesses and other non-single-family uses on the list, both new and existing (Sec. 33-97 applies the division to all customers). Devices installed before the current code that do not comply "shall be replaced." It does not cover a single-family detached home for the irrigation item. Section 33-95 lets the city, at its sole discretion, approve a less restrictive device after inspecting your system, so the list is a starting point and not always the final word.

A restaurant opening in a strip center. The center's master service may need a DC, but the restaurant's own service falls under the RP restaurant item. If both share a service connection, the RP is the device. The designer puts it on the plans before the permit is issued.

A small medical office. Medical and dental buildings are on the RP list even when they are one suite in a larger building. The tenant improvement plans should show the device.

The edge case: a tall warehouse. A two-story warehouse with high ceilings can top 34 feet from curb level. The code says "greater than three (3) stories or greater than thirty-four (34) feet," so either test puts it on the RP list, even with only two floors.

1. 1Find your business type on the 33-90 list and note the device, then check whether more than one item applies.
2. 2Get the city's approved device list from Glendale Water Services Cross Connection Control (623-930-4138, backflow@glendaleaz.com). Section 33-91 requires the device to be at least the size of the service, installed at your expense, above ground for an RP.
3. 3Show the device on your building or engineering plans. Section 33-99 requires city approval before any building or engineering permit is issued.
4. 4Get a backflow installation permit at the Development Services Center, 2nd floor, 5850 W Glendale Ave. The Backflow Tester Policy requires a permit for all new installations, including retrofits and replacements.
5. 5After installation and certification, call the permit line at 623-915-3263 for inspection: code 237 for a domestic line, 238 for a fire line, 245 for a fire hydrant meter and 246 for an irrigation line.
6. 6Have a city-certified tester test it every year. See the annual test page for the deadline and consequences.

• "A backflow device is only for irrigation." For businesses it is required by use, and irrigation is one item of 51.
• "Replacing my old device is a repair, so no permit." The Backflow Tester Policy says permits are required for retrofits and replacements of existing assemblies.
• "My landlord handles it." The code puts the duty on the customer at the service address. Ask who holds the water account.
• "Any assembly will do." Section 33-90 names RP or DC by use, and the city keeps an approved list.

The rule is Glendale City Code Sec. 33-90 on Municode, with the installation permit steps from the city's Backflow Tester Policy. The 33-90 list is in the code itself, and the city can update it. Check the current text before you order a device.