August Mack Newsletter | October, 2019

Do Warehouse have Storm Water Compliance Requirements? Maybe...
by Jeffrey Miller

Warehouse operators normally believe they are exempted from storm water permitting.  This may or may not be true depending on many factors including:

  • Standard Industrial Classification (SIC) Code or North American Industry Classification System (NAICS);
  • Activities specifically associated with outdoors (e.g. parking leaking vehicles awaiting maintenance, vehicle washing, etc.);
  • Other outdoor activities (e.g. maintenance painting, mechanical maintenance, etc.).

Warehouse operators should evaluate a facility based on the assigned code mentioned above.

Certain SIC /NAICS code warehouses are specifically regulated and listed in state regulations and/or state General Permits, or by reference in the US EPA Multi-Sector General Permit.  A warehouse should apply for storm water permit coverage when the associated code is called out in regulations and/or a permit.  In such cases, the warehouse should apply for coverage, prepare and follow a Storm Water Pollution Prevention Plan (SWP3) or apply for a No Exposure Exemption.  The utility of the No Exposure Exemption will be discussed in a paragraph below.

Some warehouses retain SIC/NAICS codes assigned to the manufacturing activity that may not be occurring at the actual warehouse.  This would be an offsite warehouse.  In this case, other activities such as performing maintenance on tractors or trailers would require storm water permitting.  Other possible activities could include parking leaking tractors, trailers, or other support vehicles.  Another possible activity would be washing tractors or trailers with the resulting wash waters being discharged to the storm water system.  US EPA developed written guidance for some of these determinations.  For example, truck maintenance and/or washing is considered an industrial activity regardless if it is indoor or outdoor.    The intent of outside parking for maintenance, indoor maintenance, washing (outdoor or indoor) along with refueling operations should be reviewed with someone experienced with storm water permitting.  Indoor activities would likely be eligible for the storm water No Exposure Exemption.

Some warehouse operations performed outside include maintenance painting or pressure washing of warehouse assets (racking, fork trucks, other).  These activities are more subjective but it is important to evaluate the scope of these activities within the intent of the General Permit.  A good compliance management strategy would be to develop a technical basis for why the General Permit would not apply; or why or why not the No Exposure Exemption would or would not apply.

The No Exposure Exemption is a document consisting of relevant warehouse information plus answers to 11 questions.  These 11 questions are specific to outdoor activities.  If the 11 questions can be answered, “No,” then it is suggested to apply for a No Exposure Certification from the regulating agency.  It should be noted the answers must be valid for five years and changes to the facility should be reviewed annually or early in a project to ensure the Exemption remains valid.  Otherwise, the Exemption is no longer valid and the warehouse should apply for coverage under the General Permit.

It should be noted that failure to follow the terms of the exemption could result in all Clean Water Act penalties available to the regulating agency.  However, in most cases, the agency would prefer the warehouse return to compliance and/or assign some additional penalties requiring additional expenditure on Best Management Practices investment rather than associated fines.  But the agency would have latitude depending on how egregious certain non-compliance discoveries are.  Some agency Notices of Violation (NOV’s) were reviewed in the development of this article including some on discovery of non-compliance associated with washing and maintenance activities.   The specific compliance requirement included development of a SWP3 which usually requires outside consulting expertise to meet the required deadline.

A storm water audit is a good starting point for determining compliance and for managing storm water risks.

Jeffrey serves as Senior Regulatory Expert for Compliance Services for August Mack. He has more than 35 years of experience in Wastewater treatment, RCRA site closures, and regulatory compliance. Mr. Miller received a Bachelor of Science in petroleum engineering and a Master of Science in petroleum engineering. He is a registered Professional Engineer in several states. Jeff can be reached at

Upcoming Events
6th annual Ohio Craft Brewers Conference
2020 Ohio Safety Congress
2020 Michigan Safety Conference

August Mack Blog Augsut Mack LinkedIn August Mack TwitterAugust Mack Google PlusAugust Mack YouTube Channel

© August Mack Environmental, Inc.