Restaurant Grease Removal Device Requirements & Support

1. What are Grease Removal Devices?
2. What is the purpose of the Grease Removal Device?
3. Why do we want to keep grease from entering the sewer?
4. Am I required to install a Grease Removal Device?
5. Where am I allowed to install a Grease Removal Device?
6. What are the types of Grease Removal Devices?
7. What size of Grease Removal Device is required?
8. What is DFU (Drainage Fixture Unit)?
9. What are flow rates and loading levels, and why are they important?
10. How often should a grease removal device be cleaned?
11. How is a grease removal device cleaned?
12. Who is responsible for maintenance and cleaning?
13. What is inspected?
14. What happens if I fail an inspection?

What are Grease Removal Devices?

Grease Removal Devices, including grease traps and interceptors, are essential tools to capture Fats, Oils, Grease, and Solids (FOGs) before it enters the sewer system. These devices work by separating grease and solids from wastewater, allowing partially treated wastewater to flow into the sewer.

What is the purpose of the Grease Removal Device?

Grease Removal Devices help protect the city infrastructure and prevent Sanitary Sewer Overflows (SSOs).Approximately 47% of sewer blockages can be attributed to grease from restaurants, homes, and industrial sources. Fats, oils, grease, and solids (FOGs) can accumulate and solidify inside the sanitary sewer, limiting flows and possibly causing blockages of flow completely. To avoid potential sanitary sewer overflows caused by FOGs, the City of Petaluma dedicates staff and maintenance time to remove the accumulations. Properly maintained grease removal devices decrease the buildup of accumulation, reducing the frequency of maintenance on sewer infrastructures, saving taxpayers money on maintenance or replacement costs. Grease removal devices are also beneficial for the facility as they protect the plumbing and waste lines that lead to the public sanitary sewer. Blockages that occur in the facilities plumbing prior to the sanitary sewer are not maintained by the City of Petaluma.

Why do we want to keep grease from entering the sewer?

Fats, oils, grease, and solids (FOGs) from kitchens and food preparation can cause significant issues when they enter the sewer system. As grease cools, it solidifies, sticking to the walls of pipes and leading to blockages, backups, and costly overflows. These blockages not only increase maintenance expenses for the City but also pose environmental risks, as untreated sewage can spill into waterways. Keeping grease out of the sewer protects infrastructure, reduces environmental damage, and ensures compliance with state and federal regulations.

Am I required to install a Grease Removal Device?

• Grease removal devices are required for all food service establishments as defined in the City of Petaluma Municipal Code 15.48.130. A food service establishment is any commercial facility discharging kitchen or food preparation wastewater including, but not limited to, restaurants, fast food establishments, delicatessens, caterers, bakeries, donut shops, halls, auditoriums with kitchens, and any other businesses that perform on-site cooking or food preparation. If you have any questions on facilities required to install a grease removal device, please contact Environmental Services at [email protected] or (707) 776-3777. 

• Any specific conditions related to a facility and its operations will be considered when determining a grease removal device requirement. The facilities production activity, plumbing infrastructure, volume and location are considered to ensure effective grease waste management.

Where am I allowed to install a Grease Removal Device?

The City of Petaluma’s Municipal Code does not determine grease removal device locations. Oversight and approval of locations are managed by the Sonoma County Environmental Health Department. Questions pertaining to the location of grease removal devices can be directed to Sonoma County Environmental Health (707) 565-6547 or [email protected].

What are the types of Grease Removal Devices?

The City categorizes grease removal devices into 3 different types: high capacity hydromechanical grease interceptor (HCHGI), hydromechanical grease interceptor (HGI), and gravity grease interceptor (GGI).   

• Hydromechanical grease interceptors (HGI) are designed to capture and remove FOGs from wastewater before it enters the sewer system. They are typically compact and suitable for food service establishments with lower drainage fixture units (DFU).
• High capacity hydromechanical grease interceptors (HCHGI) function the same as hydromechanical grease interceptors (HGI) but allow for a higher accumulation of FOGs while still maintaining removal efficiency. Manufacturers’ specifications dictate how many drainage fixture units may be plumbed to a HCHGI.
• Gravity Grease interceptors (GGI) are large devices designed to capture and remove FOGs from wastewater, relying on gravity and retention time. They are usually installed underground outside the facility. 

What size of Grease Removal Device is required? (For exact requirements please visit Petaluma Municipal Code Section 15.48.130)

The size of grease removal device required for your facility depends on the number of drainage fixture units (DFUs) that the device will serve. The minimum size required for each grease removal device is stated below.

• A minimum of 50lbs./100GPM HGI or HCHGI is required for food service establishments with <9 DFUs (Drain Fixture Units).
• Manufacturers’ specifications dictate how many drainage fixture units may be plumbed to a HCHGI
• A minimum of 1,000-gallon GGI is required for food service establishments with > 9 DFUs.

What is DFU (Drainage Fixture Unit)?

DFU, or drainage fixture unit, is a measure used to calculate the wastewater flow capacity of plumbing fixtures. This measure helps determine the size of grease removal devices needed for a business. The City of Petaluma requires businesses to comply with municipal code standards, which include installing properly sized grease traps or interceptors based on DFU and flow rate calculations. Compliance ensures the prevention of sewer blockages and adherence to City regulations. Please refer to the chart (Below) to determine the total DFUs onsite. (Table A, from Petaluma Municipal Code Section 15.48.130)

What are flow rates and loading levels, and why are they important?

• The Flow rate refers to the amount of water or wastewater passing through the device, typically measured in gallons per minute (GPM). This value helps determine the proper size and capacity of the device ensuring optimal performance.
• Loading level represents the total amount of fats, oils, grease, and solids (FOGs) that the device can retain while maintaining efficient operation. Loading levels are measured in pounds (lbs.) and indicate the maximum FOGs capacity before the device needs cleaning or servicing.
• Understanding these parameters is essential for ensuring proper device functionality, meeting municipal code requirements, preventing overflows, blockages, and minimizing environmental harm. Proper maintenance and regular cleaning of the device will help with efficiency and minimize accumulation in sewer laterals.

How often should a grease removal device be cleaned?

• The frequency of grease removal device cleaning or pump-out depends on various factors, including its removal efficiency and the total amount of grease it can hold while remaining functional. The operations of the food service facility can also affect how often it should be cleaned. How quickly a grease removal device accumulates grease can be impacted by factors such as how many dishes are being washed, how many customers are being served, the type of food being prepared, how well the kitchen staff is following best management practices (BMPs) of not pouring oil and grease in the drain, scraping plates in the garbage prior to washing...etc.
• A typical grease removal device is at maximum capacity of FOGs at 25% capacity, after which the removal efficiency starts to decrease. The 25% capacity refers to both the top oil layer and bottom solid layers which combined should not exceed 25% of the total volume of the removal device.
• Typically, HGIs (50GPM/100lbs) are cleaned once a month and gravity grease interceptors (1,000 gallons) are cleaned every two to three months. While those are the typical frequencies, they can vary based on individual factors of each food service establishment
• Each HCHGI is designed differently. The amount of FOGs each device can hold and still efficiently operator varies and will be documented in the manufacturers specifications.
• If your food service facility would like help establishing how often the grease removal device should be cleaned, City staff can help you establish a cleaning frequency that keeps the device in compliance. If you’d like help establishing a cleaning frequency you can call Environmental Services at (707) 776-3777 or email [email protected].

How is a grease removal device cleaned?

• A grease removal device can be cleaned by a 3rd party company who professionally pump-out the removal device empty.
• The food service establishment may also clean the grease removal device themselves. The device must be fully emptied to remove the solid layer at the bottom of the device when self-cleaning. When self-cleaning the city requires the facility to maintain a log with the employee initials, date, and time of the cleaning.
• Contents of the grease removal device should be properly disposed of within the requirements of the solids waste management company. If you have any questions about the appropriate way to dispose of grease removal device contents, contact Environmental Services at (707) 776-3777 or email [email protected].

Who is responsible for maintenance and cleaning?

The food service establishment* is responsible for maintaining the device, keeping detailed maintenance logs for at least the past three years, and ensuring the device is consistently in proper working condition. This includes regular cleaning, routine checks, and addressing any issues promptly to uphold operational standards.

*Unless alternative responsible party has been identified to City staff.

Inspections

The City of Petaluma is dedicated to protecting our communities, infrastructure, environment, and waterways. To prevent sanitary sewer overflows, facilities with grease removal devices are inspected by City staff to ensure compliance and proper maintenance. Staff at the facilities are required to provide access in a reasonable timeline for City staff.

What is inspected?

During inspections, the following areas are reviewed to ensure compliance and proper maintenance:

• The grease removal device:
  • Loading levels of FOGs are checked to ensure the device is not exceeding its capacity.  For HGIs and GGIs an interceptor will be considered in violation if the combined total volume of FOGs exceeds 25% of the volume.
  • The functionality of the device is checked to confirm it is working properly.
• The maintenance log:
  • For facilities that clean their own grease removal devices, this is a self-generated log documenting cleaning date.
  • For third-party maintenance, this includes records such as carbon copies of pump-out services or invoices from professional cleaning providers.
  • Failure to clean the removal devices shall be a violation and subject to enforcement action as stated in City codes and regulations.
• The facility itself:
  • Inspectors check for proper connections to the grease removal device, used cooking oil storage practices, mop sink usage, floor mat cleaning protocols, trash area maintenance, and compliance with BMPs for stormwater and environmental concerns.
  • Part of the inspection will normally involve an inspection of the trash storage area to ensure that there are no spills or untidiness, can impact the stormwater collection system.

What happens if I fail an inspection?