Industrial and Pretreatment FAQ's

    Industrial facilities and certain commercial facilities, which plan to discharge industrial waste to the City's sanitary sewer system may be required to obtain an Industrial Waste Permit. For our purposes, Industrial Waste is defined as:  

    "Any waterborne solid, liquid or gaseous waste, resulting from any production, industrial, manufacturing or food processing operation or from the development, recovery or processing of any natural resource, including waste that is required to be pretreated by Chapter 47, Section V or the City's Plumbing Code."  

    Industrial waste also includes wastes subject to specific categorical pretreatment standards at 40 CFR Parts 405-471 or regulated by 40 CFR Part 403.  

    If you are a facility wanting to discharge non-domestic wastewater into the sanitary sewer system, please contact the Industrial Wastewater Service at (832) 395-5800 or [email protected] to discuss your firm's operations, complete and submit an Industrial Waste Survey form. The Industrial Wastewater Service (IWS) will then review and follow-up with the next steps (e.g., an onsite inspection needs to be performed, a permit application needs to be submitted, a permit is not required, etc.). If the form is deficient, the customer will have to make appropriate corrections before moving to the next step.  

    You do not need an Industrial Waste Permit if your business is:  

    - a self-service or commercial (i.e., not industrial) laundry,  

    - a restaurant  

    - a car wash.  

    Additionally, the City of Houston is not currently requiring an Industrial Waste Permit for the following operations: hospitals, analytical and research laboratories, small photographic developing operations and printers. Such facilities still need to complete and submit the Industrial Waste Survey Form.  

    However, any facility discharging industrial waste to the sanitary sewer system may be required to obtain an Industrial Waste Permit if the Industrial Wastewater Service makes that determination.   

    The first step in obtaining an Industrial Waste Permit is to contact the Industrial Wastewater Service at (832) 395-5800 to discuss your firm's operations. The IWS may the perform an inspection to determine if a permit is required.  

    Once the City performs an inspection, and it has been determined your firm will require an Industrial Waste Permit, the City will send written notification that will include a permit application. The Industrial Wastewater Service also offers a pre-Application meeting to discuss the steps involved with obtaining a permit and assist new facilities with the requirements.  

    After submitting your permit application to the City, the Industrial Wastewater Service will review it and, if the application is acceptable, an Industrial Waste Permit will be issued. All facilities required to obtain an Industrial Waste Permit must pay a Permit Application Fee and a Permit Administrative Fee as established in the City's fee schedule. Industrial Waste Permits are issued for two years and are renewable after that period of time.  

    The Application and Administrative Fees are subject to change each year. Each permitted industry will receive a permit renewal notification from the Industrial Wastewater Service at least one month before their permit expires and that notification will state the current permit renewal fees.  

    The term Significant Industrial User applies to an industry that discharges to the sanitary sewer system if that industry meets the following criteria:  

    1. The industry is subject to federal regulations at 40 CFR Parts 405-471.  
    2. Any other industrial user that discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, non-contact cooling and boiler blow down wastewater); contributes a process waste stream, which makes up 5% or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or is designated as such by the control authority as defined in 40 CFR 403.12 (a) on the basis that the industrial user has a reasonable potential for adversely affecting the POTW operation or for violating any pretreatment standard or requirement.  

    SIUs are further classified as Categorical Industrial Users (CIU) if they are subject to federal discharge limitations developed by the EPA. CIUs are also subject to the City's local limits. All other SIUs are classified as Non-Categorical SIUs and are subject only to the City's local sanitary sewer discharge limits. 

    Houston enforces local limits, as mandated by the EPA and the Clean Water Act. The City also enforces guidelines set forth in City of Houston Ordinance Section V., City Code Sections 47-186 through 47-203, which gave the City enforcement authority over permit violations. Section 47-188 (General sewer use requirements) establishes the discharge limits as listed below. 

    Wastewater Table Discharge Limits

    mg/L = milligrams per liter, F = Fahrenheit, C = Celsius, S.U. = Standard Units  

    * Floating Oil and Grease is not allowed. Effective December 2, 2023, the total Oil and Grease limit is 200 mg/L. 

    •    Acids with a pH value lower than 5.0 or alkalis with a pH higher than 11.0.
    •    Sulfides in concentrations greater than five (5.0) milligrams per liter.
    •    Any liquid or vapor with a temperature exceeding 45 degrees Celsius (113 degrees Fahrenheit).
    •    Waste streams with a closed cup flash point of less than 140 degrees Fahrenheit or 60 degrees Celsius.
    •    Any flammable or explosive liquid, solid or gas.
    •    Any discharge that forms a discernable floating layer of oil and grease on the surface of the discharged water.
    •    Solid or viscous substances capable of obstructing flow in sewers.
    •    Any noxious substance that can form an objectionable or hazardous gas.
    •    Petroleum oil, non-biodegradable cutting oil or products of mineral origin in amounts that cause interference with or passes through the sanitary sewer system.
    •    Pollutants resulting in toxic vapors, gases or fumes that may cause acute utility worker health and safety problems.
    •    Any trucked or hauled waste except where the utility official has permitted a designated discharge point.
    •    Unusual concentrations of BOD, suspended solids or total dissolved solids such as sodium chloride or sodium sulfate.

    There are certain prohibited wastes that may not be discharged under any circumstances, regardless of your pretreatment classification. They are: 

    •    Flammable, reactive, explosive, corrosive or radioactive substances
    •    Noxious or malodorous materials
    •    Medical or infectious wastes
    •    Solid or viscous materials, which could cause obstruction to the flow or operation of the treatment plants
    •    Toxic substances
    •    Non-biodegradable oils
    •    Pollutants, which result in the emission of hazardous gases

    A sanitary sewer surcharge billing rate is imposed on an industrial user for discharges containing concentrations of Carbonaceous Biochemical Oxygen Demand (CBOD), Ammonia (NH3) and Total Suspended Solids (TSS) exceeding values found in domestic discharge. The City will use a predetermined formula to calculate a sanitary sewer surcharge for wastewater billing.  

    The Industrial Wastewater Service will perform an annual evaluation to determine what each permitted industry's sanitary sewer billing rate should be. The average concentrations for CBOD, NH3 and TSS from both City and industry self-monitoring are used to arrive at a sewer-billing rate. The increased sewer rates pay for the cost of the additional treatment at the City's wastewater treatment plant.  

    Treatment and removal of "high-strength" waste requires extra operating expenses, such as the cost of additional chemicals, power, solid storage capacity and final disposal. 

    Industrial facilities, which do not comply with permit requirements are subject to enforcement action. Houston utilizes a progressive enforcement response plan with actions ranging from issuance of Notices of Violation (NOVs) and Administrative Orders to sewer or water service termination and administrative fines. The key to responding to a violation notice is communication with the Industrial Wastewater Service.  

    The following is a list of the industrial categories at 40 CFR Parts 405-471 that establish effluent limits for industries that discharge industrial waste to the sanitary sewer system. If an industry performs a specific operation that is listed in one of the following categorical regulations, that industry is identified as a categorical industry. 

    New categorical regulations are currently being developed by the EPA, and this list should not be used to determine if these are the only categorical regulations that have been promulgated. 

     •    Aluminum Forming (40 CFR 467)
    •    Asbestos Manufacturing (40 CFR 427)
    •    Battery Manufacturing (40 CFR 461)
    •    Centralized Waste Treatment (40 CFR Part 437)
    •    Coil Coating, Phase I (40 CFR 465)
    •    Coil Coating, Phase II - Can Making Subcategory (40 CFR 465)
    •    Copper Forming (40 CFR 468)
    •    Electrical and Electronic Components, Phase I and Phase II (40 CFR 469)
    •    Electroplating (40 CFR 413)
    •    Fertilizer Manufacturing (40 CFR 418)
    •    Glass Manufacturing (40 CFR 426)
    •    Ink Formulating (40 CFR 447)
    •    Iron and Steel (40 CFR 420)
    •    Leather Tanning and Finishing (40 CFR 425)
    •    Metal Finishing (40 CFR 433)
    •    Metal Molding and Casting (40 CFR 464)
    •    Nonferrous Metals Forming and Metal Powders (40 CFR 471)
    •    Nonferrous Metals Manufacturing, Phase I and II (40 CFR 421)
    •    Organic Chemicals, Plastics and Synthetic Fibers (40 CFR 414)
    •    Paint Formulating (40 CFR 446)
    •    Pesticide Chemical Manufacturing (40 CFR 455)
    •    Petroleum Refining (40 CFR 419)
    •    Pharmaceutical Manufacturing (40 CFR 439)
    •    Porcelain Enameling (40 CFR 466)
    •    Pulp, Paper and Paperboard and the Builder's Paper and Board Mills (40 CFR 430 and 431)
    •    Rubber Manufacturing (40 CFR 428)
    •    Soap and Detergent Manufacturing (40 CFR 417)
    •    Steam Electric Power Generation (40 CFR 423)
    •    Textile Mills (40 CFR 410)
    •    Timber Products (40 CFR 429)
    •    Transportation and Equipment Cleaning (40 CFR 442)