National Categorical Pretreatment Standards.
Las Vegas Municipal Code § 14.17.020
in effect14.17.020 - National Categorical Pretreatment Standards.
(A) Industrial users shall comply with the categorical pretreatment standards found at 40 CFR Chapter I, Subchapter N, Parts 405—471, that apply to the regulated industrial category assigned to the user's business activity.
(B) Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Director may impose equivalent concentration or mass limits in accordance with this Section and 40 CFR Part 403.6(c).
(C) When the limits in a categorical pretreatment standard are expressed only in terms of a mass of pollutant per unit of production, the Director may convert the limits to equivalent limitations expressed either as mass of pollutant discharged per day or effluent concentration for purposes of calculating effluent limitations applicable to individual industrial users. Each such industrial user shall supply appropriate actual or projected long-term production rates for the unit of production specified in order to facilitate this process pursuant to 40 CFR 403.6(c)(2) as required by the Director.
(D) The Director may allow wastewater subject to a categorical pretreatment standard to be mixed with other wastewaters prior to treatment. In such cases, the affected industrial user shall identify all categorically regulated wastestreams and provide sufficient information for each non-categorical wastestream to determine whether it should be considered dilute for each pollutant. In such situations, the Director shall apply the appropriate formula as provided by 40 CFR 403.6(e) to determine appropriate limits.
(E) When a categorical pretreatment standard is expressed only in terms of pollutant concentrations, an industrial user may request that the Director convert the limits to equivalent mass limits. The determination to convert concentration limits to mass limits is within the discretion of the Director. The Director may establish equivalent mass limits if the industrial user meets the conditions and requirements of this subsection (E) that follow:
(1) To be eligible for equivalent mass limits, an industrial user must:
(a) Employ, or demonstrate that it will employ, water conservation methods and technologies that substantially reduce water use during the term of its control mechanism;
(b) Currently use control and treatment technologies adequate to achieve compliance with the applicable categorical pretreatment standard, and not have used dilution as a substitute for treatment;
(c) Provide sufficient information to establish the facility's actual average daily flow rate for all wastestreams, based on data from a continuous effluent flow monitoring device, as well as the facility's long-term average production rate. Both the actual average daily flow rate and the long-term average production rate must be representative of current operating conditions;
(d) Not have daily flow rates, production levels, or pollutant levels that vary so significantly that equivalent mass limits are not appropriate to control the discharge; and
(e) Have consistently complied with all applicable categorical pretreatment standards during the period prior to the industrial user's request for equivalent mass limits.
(2) An industrial user subject to equivalent mass limits shall:
(a) Maintain and effectively operate control and treatment technologies adequate to achieve compliance with the equivalent mass limits;
(b) Continue to record the facility's flow rates by a continuous effluent flow monitoring device;
(c) Continue to record the facility's production rates;
(d) Notify the Director if production rates are expected to vary by more than twenty percent from the submitted baseline production rates. The Director may reassess and revise equivalent limits as necessary to reflect changed conditions; and
(e) Continue to employ the same or comparable water conservation methods and technologies so long as it discharges under its equivalent mass limit.
(3) Equivalent mass limits under this subsection (E):
(a) Shall not exceed the product of the actual average daily flow rate of the regulated process(es) of the industrial user and the applicable concentration-based daily maximum and monthly average standards (and the appropriate unit conversion factor);
(b) Upon notification of a revised production rate, shall be reassessed and the limits recalculated by the Director as necessary to reflect changed conditions at the facility;
(c) May be retained in subsequent industrial wastewater discharge permits if the industrial user's actual average daily flow rate was reduced solely as a result of the implementation of water conservation methods and technologies, and the actual average daily flow rates used in the original calculation of the equivalent mass limit were not based on the use of dilution as a substitute for treatment as described in LVMC 14.17.015(D). The industrial user must also be in compliance with 40 CFR 403.17 (regarding the prohibition of bypass); and
(d) May not be expressed by the Director in terms of mass for pollutants such as pH, temperature, radiation, or other pollutants which cannot appropriately be expressed as mass.
(F) The Director may convert the mass limits of the categorical pretreatment standards at 40 CFR Parts 414, 419, and 455 to concentration limits for purposes of calculating limitations applicable to individual industrial users, subject to and conditioned upon the requirements of the next succeeding sentence. When converting such limits to concentration limits, the Director must use the concentrations listed in the applicable subparts of 40 CFR Parts 414, 419, and 455, and must document that dilution is not being substituted for treatment as prohibited by this Chapter.
(G) Equivalent limitations are deemed pretreatment standards for the purposes of this Chapter and Section 307(d) of the CWA. The Director must document how the equivalent limits were derived and make this information publicly available. Once incorporated into the industrial wastewater discharge permit, the industrial user must comply with the equivalent limitations in lieu of the promulgated categorical standards from which the equivalent limitations were derived.
(H) Many categorical pretreatment standards specify one limit for calculating maximum daily discharge limitations and a second limit for calculating maximum monthly average, or four-day average limitations. Where such standards are being applied, the same production or flow figure shall be used in calculating both the average and the maximum equivalent limitation.
(I) Any industrial user operating under an industrial wastewater discharge permit incorporating equivalent mass or concentration limits calculated from a production-based standard shall notify the Director within two days after the industrial user has a reasonable basis to know that the production level will significantly change within the next calendar month. Any industrial user not notifying the Director of such anticipated change will be required to meet the mass or concentration limits in its control mechanism that were based on the original estimate of the long-term average production rate.
(Ord. No. 6891, § 2, 11-6-24)
Source: City of Las Vegas, Municipal Code and City Charter (Municode Library, library.municode.com)URL: https://library.municode.com/nv/las_vegas/codes/code_of_ordinances?nodeId=TIT14PUSE_CH14.17WACOTR_14.17.020NACAPRSTFetched: 10/28/2026