Restaurant Plumbing in Phoenix and the Valley

Grease is the reason restaurant plumbing is its own trade. Fats, oils and grease (FOG) cool in the line, grab food solids and close the pipe a little more every shift. Cities treat it seriously because a blocked city sewer sends sewage out of manholes and into the street, and the city can bill the restaurant that caused it.

Phoenix requires every food service establishment that prepares food on site to have a grease interceptor. There are two kinds:

• Hydromechanical trap (the small indoor unit, often under a sink). Allowed for up to four fixtures, with no garbage disposal and no dishwasher connected. Sized by fixture count: one fixture 20 gpm and 40 pounds of grease capacity, up to four fixtures at 50 gpm and 100 pounds.
• Gravity interceptor (the big outdoor tank). Required with more than four fixtures, or with any disposal or dishwasher. Phoenix's smallest allowed size is 500 gallons, and units of 750 gallons and up need three manways.

Want the actual number for your kitchen? Our grease interceptor sizing calculator runs Phoenix's formula and Chandler's chart from the cities' own worksheets. Other cities differ, so check the Valley grease trap rules by city.

Phoenix sets a floor, not a target. Hydromechanical traps get a full pump-out and cleaning every 30 days. Gravity interceptors at least every three months. Most interceptors stop working well once grease and solids take up 25 percent of the space, so a busy fryer kitchen may need service more often than the minimum.

A few things inspectors look for every time:

1. 1The records. Three years of pump-out invoices and service records, kept on site.
2. 2The interceptor itself. Missing baffles, broken tees and rotted concrete all get written up.
3. 3The fixture count. The inspector counts sinks, floor sinks, floor drains, disposals and dishwashers to see if the interceptor is still big enough. Add a prep sink and you may have outgrown a small trap.
4. 4Outside. A clean tallow bin area with no oil on the ground.

Enzyme and bacteria drain treatments don't count as maintenance in Phoenix; the city's manual prohibits them. Grab our free printable grease trap maintenance log to keep the record straight between visits.

Maricopa County Environmental Services reviews restaurant plans before you build or remodel, and its inspectors check the plumbing against the same guide afterward. The items that trip up most openings:

• Indirect waste. Dish machines, prep and ware washing sinks, ice machines, soda fountains, dipper wells, steam tables and walk-in condensate lines can't connect straight to the drain. Each one drains through at least a 1-inch air gap above a floor sink. That's why kitchens have so many floor sinks.
• Hand sinks. One within about 25 feet of every workstation and ice machine, with no door in between, plus a splash guard when it sits within 24 inches of food surfaces.
• Hot water. At least a 50-gallon water heater with 100 percent recovery, 75 gallons with a mechanical dishwasher. Undersized heaters show up as lukewarm sinks at the dinner rush. Here's how commercial water heaters differ.

Planning a remodel? Start with the county plan review plumbing checklist before you move a single sink.

A soda carbonator ties a pressurized carbon dioxide system to your drinking water line. Maricopa County's guide calls for an approved reduced pressure backflow preventer (or another approved testable device) between the water supply and the carbonator, with its relief valve drained through an air gap to a floor sink. The fittings between the preventer and the carbonator can't be copper or brass, and the preventer has to be certified with a test report.

The building's water service needs protection too. Phoenix lists restaurants among the facilities that need an air gap or a reduced pressure (RP) assembly, and every assembly gets tested at least once a year with the results filed with the city. Not sure which assembly you have? Here's RPZ vs double check.

Ranges, fryers, woks and water heaters mean a lot of gas pipe in a small room. New appliances, moved cooklines and bigger equipment usually need a permit and a pressure test, and the pipe has to be sized for the total load or burners starve at full tilt. A gas smell during service is an emergency: get everyone out, don't flip switches or touch appliance controls, and from outside call 911 and Southwest Gas at 877-860-6020. See gas smell in a restaurant and whether you need a gas leak inspection.

We clear kitchen lines with hydro jetting, service and repair grease traps and interceptors, install and replace water heaters, run gas lines and replace backflow assemblies. We're available 24/7, and you get an upfront price before work starts. Most of the time the goal is simple: keep the kitchen open through service and fix it right after close.