Industrial and High Risk Runoff (IHRR) Inspection Program

typical areas and activities that could result in discharges of stormwater pollution

Program Overview

outside storage containment

Fairfax County’s MS4 permit requires the county to implement an industrial and high risk runoff (IHRR) inspection program.  The purpose of this program is to identify and control pollutants in stormwater discharges from industrial and commercial facilities that are most at risk of discharging a significant amount of pollutants to the county’s MS4.  This program will complement the county’s illicit discharge and improper disposal program.  A goal of this program is to assist commercial and industrial facilities in the county to implement and maintain BMPs or best management practices (see FAQ website for examples) that minimize the discharge of pollutants into the county’s stormwater drainage system.

The commonwealth of Virginia requires Fairfax County to prevent and manage the discharge of pollutants into state waterways from the county-owned stormwater drainage system. This stormwater drainage system, also known as the MS4, is the network of county-owned and maintained curbs, curb inlets, pipes, ditches and other man-made structures that receive stormwater runoff from the land and direct it to waterways. The structure through which the collected stormwater is discharged from the MS4 to a waterway is called an outfall. When it rains, pollutants such as litter, oil, grit, chemicals and bacteria flow over hard surfaces and are carried by water runoff to the stormwater drains, which lead directly to local streams, the Potomac River and ultimately to the Chesapeake Bay.  Once these pollutants are in the water, they may have harmful environmental and health impacts, including contaminating drinking water sources and impacting water quality for fish and other aquatic life.  Fairfax County is mandated by the Clean Water Act and by the Environmental Protection Agency, commonly referred to as the EPA, stormwater regulations to maintain an MS4 permit

Who is Covered?

The IHRR program applies to all industrial and high risk facilities that drain to Fairfax County’s MS4.  Fairfax County evaluates whether a facility should be considered industrial or high risk based on the following questions:

  • Does the facility hold an active Virginia Pollutant Discharge Elimination System (VPDES) permit?
  • Is the facility a municipal landfill; other treatment, storage or disposal facility for municipal waste; hazardous waste treatment, storage, disposal and recovery facility; or required to report under the Superfund Amendments and Reauthorization Act (SARA), Title III?
  • Has the facility been referred to the county for any environmental pollution concerns?
  • Has the county determined that the discharge from an industrial or commercial facility has the potential to contribute pollutants to the MS4?

Facility Inspections

Fairfax County is required to conduct inspections at industrial or high risk commercial facilities which may be the source of stormwater pollution. Industrial and commercial sites are inspected for compliance with the Fairfax County’s MS4 permit and Chapters 105 and 106 of the Code of the County of Fairfax. The typical inspection process includes three phases: using a vacuum boom


  • Contact a facility representative
  • Discuss the inspection purpose and process with facility operator or owner and answer any questions

Inspection evaluation and assessment

  • Observe the facility’s stormwater drainage system to check compliance with Fairfax County’s MS4 permit
  • Inspect outdoor structural controls and BMPs to ensure proper operation and effectiveness of pollutant reduction
  • Review results with facility owner or representative


If the inspection is deemed satisfactory, no further action is required.  If the inspection is deemed unsatisfactory, the county will:

  • Send a copy of the inspection report to the facility owner or representative
  • Work with the facility owner or representative on any corrective actions. 
  • Determine if an IHRR facility requires a Virginia Pollutant Discharge Elimination System (VPDES) permit
  • Refer the IHRR facility to the Virginia Department of Environmental Quality (VADEQ) for follow up if a VPDES permit is required.   

For additional information, please email the Stormwater Planning Division or call 703-324-5500, TTY 711.

Contact Fairfax County: Phone, Email or Twitter | Main Address: 12000 Government Center Parkway, Fairfax, VA 22035
Technical Questions: Web Administrator

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