Discharge Permits

Discharge Regulation

Sewage collection and treatment systems are not designed to treat certain industrial wastes, which can damage sewers and interfere with the operation of treatment plants, or pass through the system untreated, polluting nearby water bodies like the Napa River.

In order to protect the NapaSan’s treatment plant and local water quality, NapaSan regulates the types of waste that can be discharged to our collection system by requiring permits of certain industrial sewer users. Industries and businesses that discharge “non-domestic” waste must get a Discharge Permit from NapaSan, and in some cases must implement Best Management Practices (BMPs) or a pretreatment program to ensure that their waste is safe to discharge to the sewer system.

For more information and to determine the type of permit required by your operation, contact NapaSan’s Engineering Department at 707-258-6000.

Types of Permits

  1. Categorical Industrial User
  2. Groundwater & Surface Cleaning
  3. Industrial User
  4. Special Discharge
  5. Waste Haulers
  6. Wineries & Breweries

Categorical Industrial User Permit

Categorical Industrial Users (CIUs) are defined under the Clean Water Act, and include industries that discharge wastes containing pollutants that could harm the wastewater treatment system or pass through untreated. This definition also includes any industry which discharges an average of 25,000 gallons per day or more of process wastewater to the sewer system (excluding sanitary, contact cooling, and boiler blowdown wastewater).

CIUs must implement pretreatment (pollution control) programs, monitor the water quality of their discharge, and submit reports to NapaSan. These requirements are spelled out in the permit.

Examples of Categorical Industrial Users include:

  • Circuit board manufacturers
  • Electroplating shops
  • Pharmaceutical facilities