When does Scottsdale require a grease interceptor?

Section 31-85 amends Chapter 10 of the 2021 IPC. It rewrites IPC 1003.1, and the operative sentence is the one quoted in the key facts above. The section lists three triggers:

1. 1A new facility.
2. 2An existing facility with no interceptor that adds, alters or remodels.
3. 3An existing facility with no interceptor that has caused a blockage or is contributing to fats, oil or grease build-up in the city sewer.

A fourth sentence covers facilities that already have an interceptor: if an addition, alteration or remodel will increase the volume going to it, the interceptor must be sized for the new volume. Section 1003.1.1 adds that an interceptor or separator is single-user only.

• Interceptor or separator: a tank or device that holds back grease, oil or sand so it does not reach the sewer. The code uses the same word for small in-kitchen traps and large underground tanks.
• Grease-laden waste: waste from fixtures where fats, oils or grease can go down the drain. The code lists the fixtures rather than defining the phrase.
• Single-user only: one interceptor per business. The code does not say what a landlord with several tenants should do, so a shared tank is a design question for plan review, not something the text allows.

IPC 1003.3.1, as Scottsdale amends it, requires the interceptor to receive drainage from fixtures and equipment with grease-laden waste in food preparation areas. The fixtures named are service and mop sinks, pot sinks, pre-rinse sinks, soup kettles or similar devices, wok stations, floor drains or sinks into which kettles are drained, automatic hood wash units and dishwashers. The city's own guidelines PDF still prints an older version of this sentence that says "dishwashers without pre-rinse sinks". The Municode text, which governs, says dishwashers. The same section says the interceptor may receive waste only from fixtures that let fats, oils or grease through.

Two more amendments limit what goes in. Section 1003.0 says domestic wastewater shall not be discharged to an interceptor, so restrooms stay on their own line. Section 1003.0.1 bans wastewater above 140 degrees Fahrenheit or with a pH below 5.0.

It covers restaurants, hotel kitchens, hospitals, school kitchens, bars, factory cafeterias and clubs, and any other facility with grease-laden waste in a food preparation area. Owners and tenants carry the duty, and the contractor builds to it. It does not cover home kitchens. Sections 49-95 and 49-163 of the city's sewer code exclude domestic and residential users.

A new cafe in a shell space. The tenant improvement counts as a new facility, so the drawings must show every food-prep fixture routed to an interceptor.

A pizza shop that adds a dish machine. The shop already has an interceptor. The addition raises the load, so the tank must be recalculated for the new fixture count.

The edge case: no remodel, but a blockage. A long-running restaurant never touched its kitchen, so triggers 1 and 2 do not apply. When grease causes a blockage in the city sewer, trigger 3 applies and it must install one. Section 1006.5 also makes the property owner pay for cleanup of a sanitary sewer overflow the city has to clean up on private property.

1. 1List every fixture in the kitchen and mark which ones can receive fats, oils or grease.
2. 2Decide the interceptor type and size using the sizing rules on our Scottsdale sizing page.
3. 3Prepare the submittal package described on the submittal page and file it through the Digital Plan Submittal program.
4. 4Plan the maintenance program before you open. The FOG program page covers cleaning intervals and records.

• "Only new restaurants need one." The code also catches remodels and blockages.
• "A hand sink counts as grease waste." The list does not include hand sinks, but the city's guidelines say hand sinks in food prep areas count in the sizing unless the plumbing sheet carries a note excluding them.
• "Restrooms can share the line." Section 1003.0 bars domestic wastewater from the interceptor.

This page summarizes the code. The adopted text on Municode governs.