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Indiana Department of Environmental Management

IDEM > Permitting > Water Permits > Wastewater Permits > Municipal Wastewater Permits > Municipal Permits Overview Municipal Permits Overview

The National Pollutant Discharge Elimination System (NPDES) permit program is authorized by Section 402 of the Clean Water Act. NPDES permits are issued by the State of Indiana through the implementation of a memorandum of agreement with the U.S. Environmental Protection Agency. The purpose of the NPDES permit is to control the point source discharge of pollutants into the waters of the State such that the quality of the water of the State is maintained.

The following definitions are contained in Title 327 of the Indiana Administrative Code, Article 5, Rule 1, Section 2:

Point Source:
any discernible, confined and discrete conveyance, including, but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system, vessel, or other floating craft from which pollutants are or may be discharged.
Pollutant:
includes, but is not necessarily limited to: dredged spoil, incinerator residue, filter backwash, sewage, garbage, sewage sludge, munitions, chemical wastes, solid wastes, toxic wastes, hazardous substances, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and other industrial, municipal, and agricultural waste discharged into water.
Waters of the State:
such accumulations of water, surface and underground, natural and artificial, public and private, or parts thereof, which are wholly or partially within, flow through, or border upon this state. The term does not include any private pond, any off-stream pond, reservoir, or facility built for reduction or control of pollution or cooling of water prior to discharge unless the discharge therefrom causes, or threatens to cause water pollution.

Municipal Wastewater Treatment Facilities may legally discharge treated wastewater into waters of the state of Indiana. The facilities must first obtain a National Pollutant Discharge Elimination System Permit, also known as a NPDES Permit.

To obtain a Municipal NPDES Permit, an application package must be filed with the Municipal Permits Section of the Office of Water Quality. Facilities that have an average design flow or a proposed average design flow of one million gallons, or more, per day of treated sanitary waste water and/or serve a population equivalent of 10,000 or greater are considered major municipal systems and are required to file the EPA General Information Form, known as Form One and the Standard Form A - Municipal. Systems with an average design flow of less than one million gallons per day, or the proposal of such a discharge, are considered minor municipal systems and must file the Minor Municipal and Semi-Public Application Package. This includes minor municipal facilities, and semi-publics, as well as state and federally owned treatment plants.

New facilities must submit the appropriate application forms at least one hundred and eighty (180) days prior to the expected date of the first wastewater discharge. Existing facilities must submit the appropriate application forms at least one hundred and eighty (180) days prior to the expiration date of the existing NPDES Permit.

Municipal, Semi-Public, State, or Federal (sanitary-type discharger):

  1. Major - A facility owned by a municipality with a design flow of 1 Million Gallons per Day (MGD) or greater and/or a population equivalent (PE) of 10,000 or greater (i.e. cities, towns, regional sewer districts, etc.)
  2. Minor - Any municipally owned facility with a design flow of less than 1 MGD and /or a PE of less than 10,000 (i.e. cities, towns, regional sewer districts etc.)
  3. Semi-Public - Any facility not municipally, State or Federally owned (i.e.- mobile home parks, schools, restaurants, etc.)
  4. State Owned - A facility owned or managed by a State agency (state parks, prisons, etc.)
  5. Federally - A facility owned by a federal agency (military owned installation, national park, federal penitentiary, etc.)

Overview of the NPDES Permit

The NPDES permit controls point source discharges of pollutants into the Waters of the State through the establishment of effluent limitations and operating requirements. Generally, a NPDES permit is developed in the following manner:

  1. Identification of all pollutants known or believed to be present in the effluent. Review of all existing information in the application and the IDEM files such as effluent quality data, current permit conditions, inspections, construction permits, and compliance status.
  2. Determining applicability of EPA technology-based effluent guidelines for a discharger and the limits based on the guidelines. If EPA guidelines don't exist, development of effluent limits based on best professional judgment of the technology representing the best available treatment.
  3. Determining water quality-based effluent limits for pollutants required by EPA guidelines as well as any additional pollutants believed to be present in the effluent. Water quality- based effluent limits take into account characteristics of the receiving stream such as the low flow value and hardness of the stream at the point of discharge.
  4. The permit is drafted with the effluent limits based on either the technology-based limits or water quality-based effluent limits, whichever are more stringent.
  5. The permit may contain a time schedule for the permittee to achieve compliance with effluent limits that were either not included in the previous permit or are more stringent than the effluent limits in the previous permit. This schedule of compliance is included in the permit only if it is determined that the permittee is unable to meet the limits at the time of permit issuance. If the permit applicant is a new facility or an existing facility that is recommencing its discharge, they are not allowed a schedule of compliance.

Prior to issuance, the permit is placed on public notice for a minimum of 30 days to receive comments from the public and the permittee. During the public notice period, any interested party, including the permittee, may request that a public hearing be held to allow those in attendance to present oral and written comments to the IDEM regarding conditions of the permit.

The IDEM must respond to all oral and written comments prior to or in conjunction with the issuance of the final permit. If permit conditions are significantly changed in response to the comments, the permit may be placed on public notice for another 30-day period with the opportunity for a public hearing. There is no limit on the number of times that a permit may need to be public noticed prior to issuance.

After permit conditions are finalized, the permit is issued. Any affected party may request an adjudication of the permit including a stay of any contested permit condition within 18 days of permit issuance. If adjudication is not requested within 18 days, the permit becomes effective. The permit can be effective for no more than five years unless the permittee applies for a renewal of their NPDES permit prior to the expiration date of their existing permit in which case the existing permit is automatically extended until the effective date of a new permit.