When does Paradise Valley require a grease, oil or sand interceptor?

The trigger: "Grease, oil and sand interceptors shall be provided when, in the opinion of the Town Engineer, they are necessary for the proper handling of liquid wastes containing grease or oil in excessive amounts or any flammable wastes, sand, and other harmful ingredients." The exception follows in the same sentence: "such interceptors shall not be required for private living quarters or dwelling units."

The next three sections finish the rule:

• 15-2-16, type and location. "All interceptors shall be of a type and capacity approved by the Town Engineer and shall be located as to be readily and easily accessible for cleaning and inspection."
• 15-2-17, construction. Grease and oil interceptors are built of impervious materials "capable of withstanding abrupt and extreme changes in temperature," of substantial construction, water-tight, with easily removable covers. Bolted covers must be gas-tight and water-tight.
• 15-2-18, upkeep. "Where installed, all grease, oil and sand interceptors shall be maintained by the owner, at his expense, in continuously efficient operation at all times."

The number that gives the word excessive its teeth sits in Sec. 15-2-12. No one may discharge into a public sewer "Any water or waste which may contain more than one hundred (100) parts per million by weight of fat, oil or grease."

• Interceptor. A tank or device in the drain line that separates grease, oil or sand from wastewater before it reaches the sewer.
• Town Engineer. The Town official who decides when an interceptor is necessary and approves its type and capacity.
• Excessive amounts. Not defined in 15-2-15. The 100 parts per million fat, oil and grease limit in 15-2-12 is the closest measurable line in the same article; reading it as the benchmark is an inference.
• Private living quarters or dwelling units. Homes and residential units, which are excluded.
• Preliminary treatment. Under 15-2-13, pretreatment the Town Engineer approves in writing before construction when wastewater carries prohibited substances.

Owners and operators of non-residential properties in Paradise Valley that send kitchen, wash or shop waste to a public sewer: resort kitchens, club dining rooms, restaurants and any facility with oily or sandy waste. The owner carries the maintenance duty.

This does not apply to private living quarters or dwelling units, including a resort's private residences. Many Paradise Valley properties are on septic rather than sewer; the Town's Sewer page sends septic questions to the Maricopa County Environment Services Department, 602-506-0715.

A resort kitchen renovation. The plans add a combi oven line and pot sinks. The Town Engineer reviews the type and capacity, and the design places the interceptor lids in a service drive where crews can reach them, meeting 15-2-16.

A club that changed its menu. A bar adds a fryer menu, and grease starts showing up downstream. The Town can treat the waste as containing grease "in excessive amounts" and require an interceptor, with 15-2-12's 100 ppm line as the measurable limit.

The edge case. A residence on a resort property has its own kitchen. The answer flips to not required: 15-2-15 excludes "private living quarters or dwelling units," even when the same parcel's restaurant needs one.

1. 1Find your sewer provider. The Town's Sewer page says there are two: City of Phoenix Water Services, or the Town of Paradise Valley "operated and maintained by the City of Scottsdale."
2. 2Submit kitchen drainage plans with the interceptor type and capacity for Town Engineer approval before construction.
3. 3Locate covers where they can be opened for cleaning and inspection.
4. 4Set a pumping and inspection schedule with a licensed pumper, and keep the interceptor in efficient operation, per 15-2-18.
5. 5For Town-operated sewer problems, Scottsdale's line is 480-312-5650, 24 hours.

• Myth: no fixture count, no requirement. In Paradise Valley the trigger is the Town Engineer's opinion, not a fixture table.
• Myth: the Town maintains the interceptor. The owner does, at the owner's expense.
• Myth: a resort's homes are treated like its kitchen. Dwelling units are excluded.
• Myth: some grease in the line is fine. The Town caps discharges at 100 parts per million fat, oil or grease by weight.