Towns of Cary and Morrisville

Grease Interceptor Installation and Inspection Process

Preliminary Information

The owner, engineer or architect should refer to the Town of Cary Website for food service establishment fats, oils and grease control applicability and requirements, and contact the Town of Cary Utilities Department Pretreatment Division at (919) 319-4564 or (919) 462-2072.

During project design and development, Town of Cary grease interceptor and plumbing code requirements need to be considered and incorporated in the plumbing design plan. Local health code officials, such as those at the Wake County Environmental Services or the North Carolina Department of Agriculture, should be consulted for requirements, as they may affect the number and type of kitchen fixtures required for a food service establishment (FSE). The Fats, Oils and Grease Control Program requirements are intended to protect the Town’s wastewater collection and treatment system.

Items to consider when designing a grease interceptor system:

• Determine if the project is considered a food service establishment and is required to meet the Town’s Fats, Oils and Grease Control Program requirements
• Determine if physical constraints exist for the installation of a properly sized grease interceptor in a pre-existing facility
• Have clear understanding of plumbing equipment schedules
• Garbage disposals and waste food grinders are required by Town of Cary municipal sewer use code to connect to an appropriately sized grease interceptor. Grease interceptor sizing is increased to account for food solids and grease accumulation.
• Review requirements of other local agencies (Wake County Environmental Services, NC Department of Agriculture, Plumbing Code, etc.)
• Placement of grease interceptor (accessibility, vehicular/foot traffic, odor, etc.)
• Grease interceptor sizing related to service frequency requirements. Over sizing may result in reduced cleaning frequencies; however, it may also lead to odor issues and difficulties in adequate and effective cleaning
• Existing or proposed sewer and plumbing elevations
• Future possibilities of facility kitchen expansion or changes in menu that could alter the grease interceptor adequacy
• Community grease interception (grease interceptor shared and used by more than one FSE)
• Time or initiation of grease interceptor installation; during utilities installation or building construction
• Contact the Town of Cary Pretreatment Division for preliminary review of grease interceptor proposals

Items needed for grease interceptor sizing:

FSE layout/proposals may include any of the following, but are not limited to:

Total number and Dimensions (inches)

• 1, 2, 3-compartment sinks and drain size
• Utility sinks
• Grease contributing equipment (rotisserie, Chinese stove (wok), tilt kettles, etc.)

Discharge flow rate (gallons per minute) per manufacturer specifications

• Dishwashers
• Pre-rinse sinks and drain size (faucet supply flow rate)
• Prep sinks and drain size (faucet supply flow rate)
• Can Wash/Mop sink hose bibs (faucet supply flow rate)
• Garbage disposals/Food Waste Grinders/Pulpers (water supply flow rate)
• Exhaust Hood(s) (self cleaning, water supply flow rate)
• Kitchen floor surface area - square footage (sum of cooking, food prep, serving, and dishwashing areas)

Using the Town of Cary Grease Interceptor Sizing Spreadsheet, include all applicable sink dimensions, flow rates, pipe diameter and floor surface area. Once you have sized the grease interceptor, contact the Pretreatment Division at (919) 319-4564 or (919) 462-2072 for review and approval. Equipment and information used in sizing grease interceptors shall be reflected in the building plumbing plan submittal.

Permit Application and Plan Review Submittal

The owner, engineer or architect should refer to the Town of Cary Inspections & Permits Department website for permit application and plan submittal requirements in the Town of Cary. Projects located in the Town of Morrisville shall refer to the Town of Morrisville Inspections Department website at Town of Morrisville Inspections Department for permit application and plan submittal requirements.

Plan review submittals with information pertaining to the installation of a grease interceptor should include:

New Construction, Major Renovation Existing Facilities - Plan Submittal

1. Project owner name
2. Proposed facility name
3. Project location
4. Project design group information/engineer (sealed by PE)
5. Plumbing equipment schedule
6. Plumbing plan layout (sewer, greasy waste, and storm (if applicable)
7. Isometric plumbing layout
8. Kitchen equipment schedule
9. Grease interceptor sizing spreadsheet summary (sink types, dimensions, sink drain pipe size)
10. Grease interceptor location (proximity to kitchen, service, potential odors)
11. Grease interceptor detail and size (Town of Cary Design or Town approved design)
12. Grease interceptor construction material type
13. Grease interceptor traffic rating (H-20 bridge loaded required if subject to vehicular traffic)
14. Inlet and outlet sanitary tee design detail (Town of Cary Design)
15. Grease interceptor sample vault detail (Town of Cary Design)

Existing Facility with pre-approved alternative grease interception – Plan Submittal

1. Project owner name
2. Proposed facility name
3. Project location
4. Project design group information/engineer (sealed by PE)
5. Plumbing equipment schedule
6. Plumbing plan layout (sewer, greasy waste, and storm (if applicable))
7. Isometric plumbing layout
8. Kitchen equipment schedule
9. Kitchen equipment layout
10. Grease trap manufacturers spec sheet with make, model, design
11. Grease interceptor location (proximity to kitchen, service, potential odors)
12. Type of installation (on-floor, in-floor, exterior)
13. Type of fixture connection (direct, in-direct)

In-field Grease Interceptor Installation Inspections

The Town of Cary Pretreatment Division will conduct in-field inspections to confirm the size, design and installation of plan review approved grease interceptors. The plumbing contractor or engineer should contact the Inspections & Permits Department to schedule the following Pretreatment Inspections:

Groundwork Grease Interceptor Inspection (U100) – Inspection of all below slab or in-ground grease interceptor installations. It is expected that the interceptor (with sample vault, if applicable) will be installed in the proper orientation, level, correct size/design, and interceptor risers/covers installed prior to back filling the excavated site. At the contractors’ discretion, groundwork inspections may include the installation of inlet and outlet sanitary tees, baffle wall grouting (sides and bottom – if needed) and sample vault slope installation; however, these inspections are typically associated with a rough-in inspection.

Rough-In Grease Interceptor Inspection (U200) – Inspection of inlet and outlet sanitary tees, baffle tees, grouted baffle wall (sides and bottom - if needed) and sample vault slope installation. In special cases the inspection of all grease waste plumbing lines that are located in the wall for special case/alternative interior grease interceptors prior to covering with wall finishes.

Final Grease Interceptor Inspection (U300) – Inspection of grease interceptor risers/covers at final finish grade and review of installed sink fixtures connecting to the interceptor. It is expected that the grease interceptor access will be at a minimum flush with final finish grade and all noted corrections from previous inspection complete.

Failure to complete previously noted deficiencies or complete installations at the appropriate inspection phase may result in the issuance of a $50 re-inspection fee.

Note: Town of Cary Pretreatment Division plan review, inspection and approval are strictly for adherence to the Town's Sewer Use Ordinance requirements. All Building and construction code requirements shall be administered by the qualified local code enforcement official. Pretreatment Division review and approval shall not be construed as a building or construction code official review or approval.

If there are any questions regarding the installation of a grease interceptor or the required inspections, please feel free to contact the Pretreatment Division at (919) 319-4564 or (919) 462-2072.