What is Pretreatment?

Pollution prevention and effective wastewater treatment begins with local businesses.  Pretreatment is the removal of certain harmful pollutants from wastewater before it is discharged to the sewer system.  Wastewater treatment is a complex process involving many biological, chemical, and mechanical processes.  The Ellis Creek Water Recycling Facility is designed to receive and treat domestic and commercial sanitary wastewater, but high strength wastewater from industrial production can overwhelm the treatment process.  Pretreatment of wastewater from these facilities ensures that harmful pollutants do not interfere with the normal treatment methods employed, or pass through the treatment process and enter the environment at dangerous concentrations.

The Environmental Services Pretreatment group works with the Ellis Creek Water Recycling Facility, various local and State agencies, and the United States Environmental Protection Agency (EPA) to determine local limits for pollutants in wastewater before it can be discharged to the City’s sewer system.  Wastewater permits establish pollutant limits and other important discharge parameters for industrial and commercial businesses.  Importantly, even businesses not typically permitted by the City (e.g. restaurants/food processing facilities, dental facilities, and auto mechanic shops) are still responsible for certain levels of wastewater pretreatment as defined by the City of Petaluma’s Municipal Code.

What is an Industrial Wastewater Permit?

An Industrial Wastewater Permit defines the conditions a business must follow to discharge wastewater to the City’s sewer system. These wastewater conditions might include discharge amount, rate of flow, and strength of waste. The permit also defines reporting requirements, e.g., how often a business must provide updated information on operations related to its wastewater discharge.  You need this permit if your business discharges wastewater as part of its manufacturing processes or other operations. If your business produces a large volume of wastewater and/or "high strength" wastewater, you might need to install special equipment to comply with the City of Petaluma’s municipal code.

The types of businesses that need this permit include:

  • Beverage Producers: e.g., beer, wine, spirits, kombucha, and milk
  • Food Producers: e.g., cheese, ice cream, nut products, and bread
  • Meat processing and packing facilities
  • Large-scale fruit/vegetable processors and/or packagers: e.g., sauces, jams, oils, and pickled vegetables
  • Pharmaceutical Producers
  • Metal-working industries that produce wastewater: e.g., machine shops, and metal plating shops
  • Producers of personal care products: e.g., soaps, shampoo, and health care products
  • Print shops
  • Producers of plastic materials or products

You will need to submit a short survey to determine whether you will have to apply for a permit.  In this short survey you will describe the details of your business and how it relates to the wastewater you intend on discharging to the City sewer system. Contact the Environmental Compliance Inspector (707-776-3777) in the Environmental Services Division to identify whether you'll need the permit and how to apply.

There are no costs associated with the application or receiving of a wastewater discharge permit.  All subsequent inspections that might be performed under the permit are free of cost.  The application review process primarily involves the Environmental Services team. However, if special equipment needs to be installed, additional permits from the Building Division and the Fire Prevention Division will be needed. Processing time can take several months depending on the project's complexity.

Special Discharge Permits

What if I’m not a permanent business in Petaluma but am working on a project which will generate wastewater?

Certain temporary projects such as construction (e.g. excavation, dewatering, pipe testing) and environmental remediation (e.g. treating contaminated groundwater) will require periodic discharges to the City’s sewer system.  The Environmental Services Pretreatment group can issue temporary Special Discharge Permits which allow and regulate discharge of pretreated wastewater into the sewer.  These permits are much like Industrial Wastewater Permits but generally are for projects lasting less than one year in duration and define certain local limits for pollutants, discharge and flow limitations, and pretreatment guidelines.  To request a permit application or more information on Special Discharge Permits, please contact the Environmental Compliance Inspector (707-776-3777).


All commercial kitchens have the potential to introduce dangerous amounts of fats, oil, and grease (FOG) into their own plumbing pipes and eventually into the City’s sewer system.  FOG can come from meat scraps, cooking oils, salad dressing, butter, lard, shortening, and many more processed food materials.  When FOG from these products ends up down the drain, it quickly accumulates in plumbing and sewer pipes and can cause dangerous and costly backups and clogs.  Unregulated FOG discharged down the drain, the resulting sanitary sewer overflows and the cleaning of sewer lines cause an estimated $30,000 in repairs and maintenance a year.  In some cases the cost of cleanup of these events can be passed on to commercial users if a business is found to have significantly contributed to a FOG blockage that the City must repair.

Specialized equipment such as Hydromechanical Grease Interceptors (HGIs) and Gravity Grease Interceptors (GGIs) dramatically decrease FOG problems in pipes and in many cases may be required by the City’s Municipal Codes.  These devices work to separate fats, oil, grease, and solids from water and keep them within the interceptor while the water safely enters the plumbing system.  As FOG accumulates within HGIs and GGIs, it is the responsibility of business owners to pump and clean them on a regular schedule to ensure these devices work properly and that FOG does not spill out and into pipes.  The Environmental Services group works to mandate the installation of Grease Interceptor devices and regulate their use, and may conduct periodic inspections to enforce limits specified in the City’s Municipal Code.  More information and the City’s Municipal Code pretreatment requirements for Food Service Facilities can be found here.

Pretreatment for Dental Facilities

The City of Petaluma’s Municipal Code requires dental facilities to ensure that mercury from amalgam waste does not enter the sewer system in wastewater.  Mercury is a potent neurotoxin that is especially detrimental to aquatic life if released into the environment via wastewater.  According to the U.S. EPA, dental facilities are the main sources of mercury pollution in municipal wastewater.  The City of Petaluma has been requiring dental facilities to pretreat their wastewater to prevent mercury contamination since 2012, primarily through the use of amalgam waste separators and other best management practices.  The U.S. EPA has announced their intention to make similar pretreatment measures a federal requirement by 2020.

The Environmental Services Pretreatment group provides guidelines for appropriate pretreatment methods for removing amalgam waste before discharging wastewater to the City’s sewer system.  More information, the City’s Municipal Code requirements and best management practices for Dental Facilities can be found here.

Pretreatment for Auto Facilities

The City of Petaluma prohibits discharge of petroleum oils and other hazardous materials commonly used in auto mechanic, auto body, and service facilities to the sewer.  Auto-fleet and other facilities that commonly wash cars and trucks with chemicals and detergents are also subject to pretreatment standards as defined by the City’s Municipal Code.  The Environmental Services Pretreatment group performs periodic inspections of all auto-related facilities to ensure adequate pretreatment methods are in place and best management practices for minimizing pollution are followed.  More information on the City’s Municipal Code requirements and best management practices for Auto Facilities can be found here and here.


If you have questions related to any pretreatment matter or about what pretreatment permits or guidelines your facility might fall under, please contact the Environmental Compliance Inspector (707-776-3777).

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