FOG Program (Fats, Oils, Grease)

What is FOG?

Grease removed from the Influent at Hendersonville's WWTF

Grease removed from the Influent at Hendersonville's WWTF

July 16, 2022

FOG is made up of any fats, oils, and grease that has the potential to end up in the sanitary sewer system. Most FOG is non-soluble, meaning it cannot dissolve into water. This property causes FOG to collect in sewage collection systems, leading to costly blockages. 

Why is FOG a problem?

When FOG is discharged into our sanitary sewer system, the ability to collect and treat wastewater is affected. In addition to causing blockages in the sewer lines, FOG build up can cause sewer backups into homes and businesses or even cause a Sanitary Sewer Overflow (SSO).

Greaseberg at the infulent pump station at Hendersonville's WWTP

"Greaseberg" at Hendersonville's WWTF

April 20, 2023

What can be done to prevent FOG problems?

The best way to prevent FOG issues, is to keep FOG from going down the drain. Best Management Practices (BMPs) are steps that can be taken in the kitchen to ensure FOG is not going down the drain. In your home, practicing BMPs is usually enough to avoid problems. In restaurants, or any other large kitchen setting, a Grease Removal Device must also be installed. 

Click here for FOG Best Management Practices

What is a Grease Removal Device (GRD)?

A GRD is a plumbing device designed to remove most grease and solids before they enter the sanitary sewer collection system. GRD can be thought of in two (2) categories; grease traps and grease interceptors. 

Grease Trap

A grease trap is a plumbing device designed to remove grease from the liquid waste stream that is located under sinks or other fixtures inside of a food service establishment.A grease trap under the sink

Grease Interceptor

A grease interceptor is a larger plumbing device located underground, also designed to collect grease and solid wastes and prevent them from entering the sanitary sewer system.

Underground grease interceptor

Does my establishment need a GRD?

The Hendersonville, NC Policy and Procedures for the Management of Fats, Oils and Grease (FOG) sect. 52-258 part b states: "All Food Service Establishments and Mobile Food Units connected to, whether permanent or temporary, the City's sewer collection system shall comply with the FOG policy". More details for requirements for a specific establishment can be obtained by filling out a Food Service Establishment Application. 

Click here for Food Service Establishment Application


Fats monsterFats can be commonly found in nuts, seeds, fish, red meat, butter, cheese, ice cream, avocados, ect. When any of these food products are discharged down the drain, the fats contained within these food items will start to coat the inside of the pipe, and will build up over time.


Oils monsterOils are non-soluble solutions found in cooking oils, mayonnaise, salad dressings, ect. Oil and water do not mix, leaving the oils to often float on top of the wastewater being discharged allowing it to separate and remain in the collection system.


Grease monsterGrease comes from meat fats, shortening, salad dressings, and dairy products. Grease is often liquid at cooking temperature, but if discharged into the sewer system, that grease will cool and turn back into a solid which wastewater can't pass through.

Elizabeth "Gracie" Erwin
Utilities Compliance Coordinator
(828) 697-3057
Kasey Sudderberg
Utilities Compliance Technician
(828) 341-7072