Paints & Coatings Resource Center

Plain English Guide to Regulations
Wastewater Discharges

How to Comply

This compliance tool is intended mainly for coating facilities that discharge wastewater to a city sewer system (referred to as publicly owned treatment works, or POTW). These coating facilities are termed indirect dischargers. If your facility discharges to a water body (stream, river, bay, etc.), it is a direct discharge facility. Follow this LINK for information on direct discharge regulations.

Process wastewater is frequently generated from cleaning, phosphating and other surface preparation steps associated with coating operations. Also, many paint booths generate wastewater. If your coating operation discharges process wastewater to a POTW, then you have specific responsibilities that are defined in the Clean Water Act and its associated regulations. Existing coating facilities that discharge wastewater should already be in compliance with these regulations. New sources must comply with these regulations before they begin discharging wastewater from manufacturing operations. Below is a short procedure that will assist you in determining which regulations apply, which agency you should report to, and your specific responsibilities.

  1. Determine which federal regulations are applicable to your facility.
  2. Contact your wastewater regulatory agency.
  3. Determine your permitting requirements, discharge limitations, and monitoring, reporting and recordkeeping requirements.
  4. Determine if you are required to have a storm water permit and/or need an oil spill control and countermeasure plan.

Overview of Federal Regulations

Coating facilities that discharge process wastewater to a POTW should be concerned with two sets of federal rules:

  • Some coating facilities must comply with Categorical Pretreatment Standards.
  • All coating facilities must comply with the General Pretreatment Regulations.
Of these two sets of rules, the Categorical Pretreatment Standards are the most difficult to meet. The explanation below starts by determining if the Categorical Pretreatment Standards apply to your facility.

Determine if Your Facility is Regulated by Categorical Pretreatment Standards
Some coatings facilities are covered by Federal effluent guidelines (standards/discharge limits) that have numerical limits or standards for specific pollutants. The three most commonly applicable Federal effluent guidelines for coating operations are:

Read below about each of these regulations to determine if they apply to your facility. If you are unable make a determination, you can request a category determination from EPA or your state agency.

Coil Coating Categorical Standards (40 CFR 465)
This regulation covers facilities that engage in coil coating and perform any two or more of these operations:

  • Cleaning
  • Conversion coating
  • Painting the basis material
For details on the Coil Coating Categorical Standards, click HERE.

Electroplating Categorical Standards (40 CFR Part 413)

The Electroplating Standards apply to indirect discharge coating operations that are not covered by the Coil Coating standards and perform one or more of the following operations:

For details on the Electroplating Categorical Standards, click HERE.

Metal Finishing Categorical Standards (40 CFR Part 433)
The Metal Finishing Category covers wastewater from 46 unit operations: the six operations covered by the Electroplating Categorical standards, plus an additional 40 operations. If any of the six electroplating operations are present, then the Metal Finishing standards apply to wastewater from any of the 46 listed metal finishing operations. Also, all direct discharge electroplating and metal finishing facilities are covered by the Metal Finishing Categorical Standards (i.e., the Electroplating Standards apply only to indirect dischargers).

The Coil Coating regulations take precedence over the Metal Finishing standards. Therefore, if the Coil Coating standards apply to your facility, then those are the standards that you should meet. Also excluded from the Metal Finishing rules are all existing indirect discharging job shops electroplaters and independent printed circuit board manufacturers. For these two groups of facilities, the Electroplating Standards still apply.

For details on the Metal Finishing Categorical Standards, click HERE.

General Pretreatment Regulations
If the Coil Coating, Electroplating, or Metal Finishing regulations discussed above do not apply to your facility, but your facility does discharge process wastewater to a POTW, then it is covered by the General Pretreatment Regulations (40 CFR 403). For example, if your facility only performs spray painting and only discharges water from a paint booth, it would not be covered by any of the three mentioned sets of standards. However, your facility will need to comply with the General Pretreatment Regulations.

Some provisions of the General Pretreatment Regulations only apply to significant industrial users.

For details on the General Pretreatment Regulations, click HERE.


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