General Pretreatment Program Plumbing Requirements

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The following is a general guideline designed to help direct commercial facilities to the Town of Cary Utilities Department Pretreatment Division for plumbing design and construction requirements. The Pretreatment Division enforces the Town’s Sewer Use Ordinance that protects the wastewater collection and treatment system. The Town of Cary Inspections & Permits Department application for building permits requests notification in the following areas where utility pretreatment requirements may apply.

Note: 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.

Contact the Pretreatment Division at (919) 319-4564 or (919) 462-2072 for specific pretreatment plumbing design and construction requirements.

Food Service Establishments (FSE) (Grease Interceptors/Traps)

The Town of Cary Fats, Oils, and Grease Control Program, which is located in the Sewer Use Ordinance (Section 36-183), is designed to aid in the prevention of sanitary sewer blockages and obstructions from the contribution and accumulation of fats, oils and greases into such sewer system from industrial or commercial establishments, particularly food preparation and serving facilities. FSE are required to install Town approved grease interceptor(s) and maintain said interceptor to reduce the contribution of fats, oils, and grease into the sewer system. Please note that with the renovation or fit-up of an existing food service establishment, existing grease interception, if present, must be approved by the Town for grease control adequacy.

Typical Food Service Establishments (FSE) affected by the Town of Cary Fats, Oils and Grease Control Program:

  • Restaurants
  • Cafeterias
  • Schools
  • Day care/retirement facilities (which prepare food)
  • Cafes (coffee shops/sandwich/grill facilities
  • Bakeries
  • Concession stands
  • Meat/deli/seafood facilities
  • Club houses/recreation centers
  • Churches
  • Caterers
  • Ice cream shops

Automotive and Car Wash Facilities

The Town of Cary Sewer Use Ordinance (section 36-173 (2)b. c. and (9)b.3.) prohibits the discharge of petroleum oils and debris (sand/grit) in amounts that will cause interference with the wastewater collection and treatment system. Automotive facilities are required to install oil/water separators. Car wash facilities are required to install sand/grit interceptors, along with oil/water separators.

Typical Commercial Facilities required to install sand/grit interceptors and/or oil/water separators:

  • Automotive repair
  • Hand/automated car wash
  • Equipment wash/repair
  • Lube shops
  • Apartment car wash facilities

*Trash Compactor/Dumpster Pad with Drain

* For a compactor/dumpster used only at facilities that may contain liquid wastes. Such facilities include food service establishments and apartment/residential complexes.

The Town of Cary Sewer Use Ordinance (section 36-173 (2) o.) prohibits the discharge of stormwater into the wastewater collection and treatment system.

Trash compactor and dumpster pads that include a drain to the sanitary sewer system must be covered or protected from stormwater inflow, and shall include Town specific solids interception and oil/grease interception. Compactor and dumpster pad designs that include a drain to the sanitary sewer must be approved by the Pretreatment Division.

Typical Facilities that may contain a compactor/dumpster pad:

  • Food service establishments
  • Apartments/town homes
  • Schools
  • Shopping centers
  • Residential care facilities
  • Entertainment centers

Elevator Sump Discharge

The Town of Cary Sewer Use Ordinance (section 36-173 c.) prohibits the discharge of petroleum oils in amounts that will cause interference with the wastewater collection and treatment system.

Elevator systems which employ hydraulics and include a sump pump in the elevator shaft shall not connect directly to the sanitary sewer system without approved pretreatment. Elevator sumps can connect to an approved oil/water separator with an internal wetted volume equaling 1.5 times the elevator or elevators' total hydraulic fluid capacity.  

Typical facilities that may employ elevators

  • Multi-story public buildings
  • Multi-story office buildings
  • Apartment complexes
  • Hotels

Silver Recovery

The Town of Cary Sewer Use Ordinance (section 36-173 (5.)) limits the discharge of pollutants of concern which can affect the performance of the wastewater treatment system.

Photo processing facilities which generate silver rich solutions are required to install silver recovery devices to reduce the discharge of silver into the Town of Cary Wastewater Treatment System.

Typical facilities that may employ photo processing and generate silver rich solutions include:

  • Hospitals
  • Facilities that employ X-ray photo processing
  • Veterinarians
  • Chiropractor's offices
  • Doctor's offices
  • Dental offices
  • Photo shops/color photo development

Laboratories

The Town of Cary Sewer Use Ordinance (section 36-173 (5.)) limits the discharge of pollutants of concern which can affect the performance of the wastewater treatment system.

Laboratories may conduct a multitude of wet chemistry, analytical and research projects which produce a waste product or produce glassware/equipment that requires washing. All Laboratories should have in place a chemical hygiene plan detailing the appropriate disposal of all waste products. Disposal manifests are required to be maintained for review by the Town for determination of appropriate disposal of said wastes. No disposal of waste products from a laboratory shall be discharged to the sanitary sewer without first obtaining written approval from the Town of Cary Public Works and Utilities Department director.

Typically Laboratories include sinks for the washing of glassware. Generally, with Town approval, a pH neutralization tank shall be included on all fixtures that may receive wash and rinse waters having acidic properties. All waste piping in the laboratory shall be constructed to accommodate the proposed activities of the laboratory.

Typical facilities that may contain a laboratory:

  • Commercial laboratories
  • Hospitals
  • Schools
  • Pharmaceutical operations
  • Research facilities
  • Doctor's offices/clinics

Spill Control

The Town of Cary Sewer Use Ordinance (section 36-173 (10.)) may require facilities that store bulk liquids to install spill control devices and/or implement a spill control plan to prevent the accidental discharge of bulk liquid or liquids of concern into the sanitary sewer system. Potentially damaging liquids must be contained in a manner to prevent accidental discharges.

Some typical liquids of concern:

  • Petroleum hydrocarbons (oils, fuels, lubricants, etc.)
  • Bulk chemical storage (acidic/corrosive/toxic)
  • Biocides/algaecides
  • Propylene/ethylene glycol (cooling liquids)
  • Large volumes of water
  • Detergents soaps

Note: Liquid volumes, pretreatment requirements will be evaluated on a case by case basis by the Town of Cary