IDEM Rule 6 Storm Water Permits

Alexander Lesher
January 17, 2012 — 2,112 views  
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In the state of Indiana, industrial and manufacturing facilities should be aware of the environmental requirements under Rule 6 General Permit for Discharges Associated with Industrial Activities. The Clean Water Act requires that discharges associated with industrial activities be permitted under the National Pollutant Discharge Elimination System (NPDES). If your facility already has a permit, then you may already be familiar with the general requirements such as monitoring, reporting, and documentation. Other details such as defining the permit term, due dates, appropriate sampling practices, and proper outfall designation may prove more elusive. The intent of this article is to help with comprehension on the detail and resources that you should dedicate to your program to ensure compliance with the storm water regulations.

Applicability to an NPDES Rule 6 permit is determined by a facility's Standard Industrial Classification (SIC) codes. If your industrial facility operates under one or more of the applicable SIC codes, then you are potentially subject to requiring a permit. The facility must also have industrial activities which are exposed to storm water and a direct drainage outfall from which storm water is collected and discharged.

Secondly, and critically, the permit start date and time-sensitive reporting requirements associated with it are often a point of misconception (regarding the five year permit term). The NPDES regulations state that a permit issued under this rule is valid for a period of five years from the date the commissioner receives an original Notice of Intent (NOI) letter. Misinterpreting the start and expiration date of a permit term is a potential point of noncompliance. The permit start date is clearly stated on the Notice of Sufficiency (NOS) letter sent by the Indiana Department of Environmental Management (IDEM) since it is the date the commissioner approved the NOI and assigned a permit number to the facility. The permit year is defined as the period of a year within the permit term. During this time annual reports are due. For example, if a permit term begins on March 11, 2012 and expires on March 10, 2017, the first permit year extends from March 11, 2012 to March 10, 2013 and so on. NOIs should always be submitted to the IDEM through certified mail in order to get an actual receipt date. In an attempt to address this issue, IDEM includes the actual permit expiration date in the NOS letter with all recently submitted NOIs. For facilities that are unsure of the commencement of their Rule 6 general permits, they can contact the Rule 6 Coordinator at IDEM to acquire the actual NOI receipt date in order to ensure you are operating within compliance and meeting the expected timeframe for reporting requirements. Additionally, renewals for Rule 6 permits are completed by submitting an NOI at least three months prior to the expiration of your permit term.

Under the Rule 6 general permit program, annual sampling is required at each outfall at the facility apart from outfalls established as being significantly similar in the NOI. There are eight standard annual sampling parameters for which all subject facilities must analyze (oil & grease, carbonaceous biological oxygen demand (CBOD), chemical oxygen demand (COD), total suspended solids (TSS), total Kjeldahl nitrogen (TKN) , total phosphorous, pH, and nitrate plus nitrite nitrogen). In addition, you must also include any pollutant that is reasonably expected to be potentially present in storm water discharges. For example, metals at a metal-processing plant should be sampled. This may also include any potential pollutant that IDEM has requested to be sampled. Samples are to be collected annually and analytical results must be submitted to IDEM within 30 days following the completion of the analytical testing. To comply with the standard, the permitee must understand which outfalls to sample, how they should be sampled, and how the analytical results should be submitted.

As previously stated, sampling should only be conducted at those outfalls outlined in your NOI and/or Storm Water Pollution Prevention Plan (SWPPP) and there should be one set of samples for each outfall. The storm water samples should be collected within the first 30 minutes of a qualifying rain event in order to capture the initial cleansing of the industrial facility drainage area by the storm event before storm water dilution takes place. The Rule 6 Industrial Storm Water Discharge Monitoring Report (DMR) (State Form 53590) incorporates the aforementioned Rule 6 regulatory requirements for the annual sampling event and puts them in an easy to follow, consistent format. Part C of the form requests the actual time the outfall began discharging, the duration of the discharge, and the amount of total rainfall received during the storm event. It is thus important that this information is noted and recorded at the time of sampling. Submission of the DMR to the IDEM should also include a copy of the analytical results and chain of custody.

A common point of noncompliance for Rule 6 permits are the associated due dates for conducting sampling and submitting the Rule 6 General Permit Annual Report. The first annual sampling for Rule 6 permit should be conducted within 365 days from the date of the beginning of the permit term. Subsequently, annual reports should be submitted within the permit year, or 30 days following the sampling event if the sampling was taken near the end of the permit year. For the remainder of the permit term, IDEM requests that reports be submitted within 365 days of the anniversary date of the permit start date. Copies of the state forms including the DMR and Annual Storm Water Report (in both Word and PDF format) can be found at

Another potential problem that many facilities face is trying to schedule the sampling event with the submittal due date for the Annual Report to minimize the number of submittals to IDEM. This is not a recommended practice as it is difficult to schedule around the rain and achieving a qualifying rain event. If your facility's annual report is due on February 10, 2012 and you postpone sampling until this time, you will find it difficult to coordinate sampling under proper conditions including a reasonable time of day. It is strongly recommended the sampling be conducted during the spring when qualifying rain events are common and the weather is warmer regardless of when the annual report is due. In turn, this may require submitting the DMR and Annual Reports separately.

Finally, as previously alluded, outfall designations can be a tricky point when developing an NOI. According to the definition provided in the Rule 6 general permit regulations (327 IAC 15-6-4(21)) an outfall is "the point of discharge from a point source." A point source, as defined in 327 IAC 5-1.5-40, is "any discernible, defined, and discrete conveyance, including, but not limited to, any of the following from which pollutants are or may be discharged from: pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, confined feeding animal operation, landfill leachate containment system, vessel or other floating craft." An outfall is regulated under the Rule 6 general permit when that outfall discharges storm water exposed to industrial activities into a state or federal water. Although compliance with IDEM Rule 6 Strom Water permits can be a complex responsibility for facilities, by familiarizing yourself and understanding these requirements, compliance is certainly attainable.


Alexander Lesher

August Mack Environmental, Inc.

Alexander Lesher is a staff engineer with August Mack Environmental, Inc. in the Indianapolis, Indiana office. Alexander has experience coordinating and conducting storm water sampling and permitting. Since joining August Mack he has contributed to many projects that include environmental compliance matters such as storm water management and NPDES permitting and compliance. Alexander can be reached at 317.916.3128 or [email protected]