An industrial user (IU) must comply with all applicable federal, state, and local pretreatment standards and requirements. Some federal requirements apply to all IUs and other requirements apply only to specific types of IUs.

An IU demonstrates compliance by:

• performing self-monitoring,
• submitting reports and notifications to its control authority, and
• maintaining records of its activities.

These requirements apply to each type of IU regardless of the entity serving as the control authority. These federal requirements apply regardless of whether the IU has a control mechanism (e.g., permit or discharge authorization) from its control authority.

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• Requirements for All IUs
• Additional Requirements for SIUs
• Additional Requirements for CIUs
• Requirements for Hauled Waste
• Additional information

Requirements for All IUs

All IUs are responsible for notifying the receiving POTW and/or control authority (if they are different entities) about the following discharges or changes to existing discharge practices:

• changes affecting potential for slug discharge (40 CFR Part 403.8(f)(2)(vi)) (PDF)(7 pp, 232 K).
• potential problems, including slug loadings (40 CFR Part 403.12(f)) (PDF)(10 pp, 216 K).
• noncompliance and repeat sampling report (40 CFR Part 403.12(g)(2)) (PDF)(10 pp, 216 K).
• changed discharge (40 CFR Part 403.12(j)) (PDF)(10 pp, 216 K).
• changed production (for IUs with limits calculated from a production-based standard) (40 CFR Part 403.6(c)(9)) (PDF)(7 pp, 236 K).
• hazardous wastes discharge (40 CFR Part 403.12(p)) (PDF)(10 pp, 216 K). See also Hazardous Waste Reporting Requirements for Industrial Users under 40 CFR 403.12(p)&(j).
• bypass (40 CFR Part 403.17) (PDF)(1 pg, 184 K).

These notifications alert the POTW and/or control authority to discharges that can affect the collection system or treatment plant. In addition, the control authority may specifically require its IUs to:

• submit reports, as required (40 CFR Part 403.12) (PDF)(10 pp, 216 K).
• maintain records of pretreatment activities, as required (40 CFR Part 403.12(o)) (PDF)(10 pp, 216 K).

Additional Requirements for SIUs

Because an IU can be as simple as an automated, coin-operated car wash or as complex as an automobile manufacturing plant or a synthetic chemical producer, EPA developed four criteria that define a significant industrial user (SIU):

• is subject to categorical pretreatment standards (CIUs) under 40 CFR Part 403.6 (PDF)(7 pp, 236 K) and 40 CFR chapter I, subchapter N, except those designated as NSCIUs; or
• discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, noncontact cooling, and boiler blowdown wastewater); or
• contributes a process wastestream that makes up five percent or more of the average dry-weather hydraulic or organic capacity of the POTW treatment plant; or
• is designated as such by the POTW on the basis that the IU has a reasonable potential for adversely affecting the POTW’s operation or for violating any pretreatment standard or requirement [in accordance with 40 CFR Part 403.8(f)(6)] (PDF)(7 pp, 232 K).

SIUSIU(1) All users subject to categorical pretreatment standards under 40 CFR 403.6 and 40 CFR chapter I, subchapter N, except those designated as NSCIUs; and (2) Any other IU that discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, noncontact cooling, and boiler blowdown wastewater); contributes a process wastestream that makes up 5 percent or more of the average dry-weather hydraulic or organic capacity of the POTW treatment plant; or is designated as such by the POTW on the basis that the IU has a reasonable potential for adversely affecting the POTW’s operation or for violating any pretreatment standard or requirement [in accordance with 40 CFR 403.8(f)(6)]. [40 CFR 403.3(v)]s must comply with additional requirements in the federal regulations that include, but are not limited to the following:

• Conduct required self-monitoring and submit periodic compliance reports every six months according to the reporting requirements for IUs not subject to categorical pretreatment standards (40 CFR Part 403.12(h)) (PDF)(10 pp, 216 K).
  • Ensure that self-monitoring meets applicable sample collection and analysis requirements (40 CFR Part 403.12(g)) (PDF)(10 pp, 216 K).
  • Ensure that reports meet applicable signatory and certification requirements (40 CFR Part 403.12(l)) (PDF)(10 pp, 216 K).
• Develop and implement a slug control plan, if required by the control authority (40 CFR Part 403.8(f)(2)(vi)) (PDF)(7 pp, 232 K).

Additional Requirements for CIUs

EPA develops national standards that are based on particular industrial processes. These standards are technology-based (i.e. they are based on the performance of treatment and control technologies); they are not based on risk or impacts upon receiving waters. These standards are found at 40 CFR Part 405-471.

Non-domestic dischargers subject to these national standards are called categorical industrial users (CIUCIUAn industrial user subject to national categorical pretreatment standards.s). CIUs must comply with additional requirements in the federal regulations that include, but are not limited to, the following:

• Submit to its control authority:
  • a baseline monitoring report (40 CFR Part 403.12(b)(1–7)) (PDF)(10 pp, 216 K),
  • compliance schedule progress reports (40 CFR Part 403.12(c)(1–3)) (PDF)(10 pp, 216 K),
  • a 90-day compliance report (40 CFR Part 403.12(d)) (PDF)(10 pp, 216 K), and
  • a periodic compliance report (40 CFR Part 403.12(e)) (PDF).(10 pp, 216 K) (This requirement is the CIU equivalent to the SIUs reports required at 40 CFR Part 403.12(h)) (PDF)(10 pp, 216 K).
• Notify the POTW and/or control authority of upset (40 CFR Part 403.16) (PDF)(2 pp, 184 K).

A CIU must comply with these federal requirements regardless of whether it has a control mechanism (e.g., permit or discharge authorization) from its control authority. These reports and notifications provide the POTW and/or control authority basic information on the industrial facility and regular reports on the facility’s compliance status with categorical and other applicable standards.

Additional requirements might apply if the CIU’s control authority implements optional pretreatment program provisions. The requirements should be specified in the CIU’s control mechanism. The CIU must notify its POTW and/or control authority (if they are different entities) about the following:

• Production level change in the equivalent limit calculation (40 CFR Part 403.6(c)(5)) (PDF)(7 pp, 236 K).
• Material/significant change in the alternative limit calculation (40 CFR Part 403.6(e)) (PDF)(7 pp, 236 K).
• Waived pollutant present (40 CFR Part 403.12(e)(2)(vi)) (PDF)(10 pp, 216 K).
• Middle-tiered categorical industrial user (40 CFR Part 403.12(e)(3)(iv)) (PDF)(10 pp, 216 K).

Requirements for Hauled Waste

The term “hauled waste ” refers to the wastes’ transportation method to the POTW. Hauled waste might be sewage or domestic waste, or it might include non-domestic waste, or a combination of both types of waste. If an IU has its wastes hauled to the POTW, the waste must still comply with its applicable pretreatment standards and requirements.

Additional Information

• EPA’s Effluent Limitations Guidelines – CIUs are those facilities performing processes subject to pretreatment standards for existing sources or pretreatment standards for new sources found in EPA’s Effluent Limitations Guidelines. Industry-specific guidance materials, including regulatory development documents, are found with the information for each industry category.
• Compliance Assistance Centers – Access to plain-language materials and other resources on environmental compliance for various commercial and industrial sectors.
• EPA’s New Source Dates for Direct and Indirect Dischargers Memorandum – Summarizes regulatory requirements for determining application of new source standards, including a listing of applicable new source dates used in making new source determinations
• Applicability of Categorical Pretreatment Standards to Industrial Users of Non-Discharging POTWs
  • Applicability of Categorical Pretreatment Standards to Industrial Users of Non-discharging POTWs(1 pg, 4 K)
• Applicability of Categorical Pretreatment Standards to Zero Discharge Facilities within Letter from the United States Environmental Protection Agency dated Apr 16, 1993 to Mr. Robert F. Babcock
• Applicability of Effluent Guidelines and Categorical Pretreatment Standards to Biodiesel Manufacturing
• Applicability of Categorical Pretreatment Standards to Industrial Users Conducting Research and Development Operations

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