Updated Industrial Stormwater General Permit Sampling Requirements

The new Industrial Stormwater General Permit (ISGP) sampling requirements for Washington State became effective on January 1, 2020.

The ISGP’s goal is to improve stormwater quality (and reduce pollutants in runoff) through management of stormwater at industrial sites. The ISGP originates from a combination of federal (the Clean Water Act) and Washington state (Water Pollution Control Act) law. Under the ISGP, permittees are required to implement Best Management Practices (BMPs) to reduce stormwater pollution, monitor their stormwater discharges, compare the results with benchmark values, and implement an escalating series of corrective actions depending on the number of times the benchmarks are exceeded.

What Stormwater Provisions Changed? Key Updates

Many of the key provisions didn’t change. Here is a brief summary of the key updates.

  • The five core water quality benchmarks—turbidity, pH, oil sheen, copper and zinc—remain the same, and the requirements and deadlines for implementing corrective actions if those benchmarks are exceeded remain unchanged.
  • The new permit proposes to use 2017 North American Industry Classification System (NAICS) groups to classify the sectors required to apply for permit coverage (the previous permit relied on the 1987 Standard).
  • Industrial Classification (SIC) groups to identify the sectors required to apply for permit coverage. The Clean Water Act remains based on SIC codes, and there is a not a one-to-one relationship between the two codes.
  • The Washington State Department of Ecology has changed the groundwater-related provisions with an intention to increasingly regulate infiltration of stormwater under the ISGP. For sites with a discharge point to groundwater (i.e., infiltration systems), the terms and conditions of this permit will apply. There is an exemption to permit coverage for facilities that discharge only to groundwater.
  • Permittees must sample the stormwater discharge from the first fall storm event each year (the start date for the “first fall storm event” sampling requirement has been moved from October 1 to September 1). First fall storm event means the first time on or after September 1 of each year that precipitation occurs and results in a stormwater discharge from a facility. We’ll likely see more 3rd quarter benchmark exceedances as a result, as there are fewer summer storms to sample to average with the first flush.
  • Permittees claiming “consistent attainment of benchmark” for one or more discharge monitoring parameters will now be required to collect a single annual sample in the 4th quarter.
  • Ecology has retained the provision requiring permittees that discharge to Puget Sound Sediment Cleanup Sites, including the Lower Duwamish Waterway, to conduct line cleaning and storm drain solids characterization sampling once during the permit term.
  • The new permit requires that the stormwater pollution prevention plan (SWPPP) be prepared by qualified personnel. Some additional information and details are also to be presented on figures, such as showing the property size/acreage, areas of existing and potential soil erosion that could result in the discharge of a significant amount of turbidity, sediment, or other pollutants, etc.

For more information, see the Washington State Department of Ecology website’s Industrial Stormwater General Permit page or contact Andrew Kaparos.

Diving In – The Promise of Social Marketing for Storm Water Education


Kapalua Bay on Maui

Kapalua Bay on Maui. The West Maui Kumuwai campaign uses social marketing to protect a sensitive watershed.

Individuals have a direct influence on storm water quality in their communities, and regulators strongly emphasize public education and involvement campaigns in municipal storm water management programs. But how can leaders convince residents to pick up after pets, reduce lawn pesticide use, and wash cars without getting soapy water in storm drains? And how can they discourage commercial and industrial workers from dumping contaminated liquids down storm drains behind shops, and to use drip pans to keep oil off pavement? These behavior changes would have a direct positive effect on the coastal and inland water resources we enjoy.

In traditional environmental education campaigns, the message is often delivered through newsletters, brochures, public service announcements, and social media. Some effort may be made to reach a specific audience, but the focus is producing a good quality educational tool. The hope is that having a good message and delivering it well will make people listen, learn and act.

But experience in educational campaign history indicates otherwise. Simply handing someone a pamphlet does not mean that a person will act on that information.

Enter social marketing. Social marketing integrates marketing concepts and tools from social psychology to influence behaviors that benefit individuals and communities for the greater social good.  While social marketing campaigns sometimes employ social media, the two are not the same. Social marketing can use a variety of tools to influence behaviors. First used in the public health realm, the practice focuses on a specific community. Research and surveys identify real or perceived barriers to change, and campaigns are designed to overcome those barriers and reward desired behaviors.

A great example of social marketing in action is the West Maui Kumuwai (WMK) campaign in a sensitive watershed on Maui. WMK is a non-profit that shines a spotlight on the actions of everyday people to promote ocean health. Through community surveys, WMK identified landscaping activities as a community concern relative to storm water pollution. WMK’s Reef-Friendly Landscaper campaign invites landscapers and gardeners to “Take the Pledge” by agreeing to a set of ocean-friendly landscaping activities. WMK then promotes those companies on its website and through social media, to keep these companies engaged and committed.

If you’ve heard of other successful social marketing campaigns related to storm water education, please let us know with a comment.

For more information about storm water services for municipalities, construction, and industry, contact Janice Marsters at