A walkthrough of California's Industrial General Permit: who needs coverage, how to choose between NOI, NEC and NONA, and what to do after a Numeric Action Level exceedance, including Level 1 and Level 2 steps.
California's industrial stormwater permit is the State Water Resources Control Board's Industrial General Permit (IGP), in effect since July 1, 2015. The requirements below describe the permit as it took effect in 2015, so check the current order on the State Water Board's IGP page before relying on them. If your facility's SIC code is on the regulated list and it discharges stormwater associated with industrial activity, you file a Notice of Intent for full coverage. If nothing industrial is exposed to rain, you can certify No Exposure instead, and if you are on the list but do not discharge, you file a Notice of Non-Applicability. All three filings go through the SMARTS database.
Who falls under the permit
Coverage depends on two things: your SIC code, and whether industrial activity actually contributes to a stormwater discharge. The Board's list of regulated SIC codes follows the federal regulations, and the Los Angeles Regional Board's IGP page links the 1987 SIC manual used to look up your code. The 2015 permit has nine industrial categories, down from 11 under the 1997 permit, but it reaches more business types, including light industries such as wineries and breweries (WEF Stormwater Report).
A listed SIC code alone does not force you into full coverage. A facility on the list that has no stormwater discharge associated with industrial activity does not need IGP coverage, but it has to say so formally.
Choosing a coverage path
| Notice of Intent (NOI) | No Exposure Certification (NEC) | Notice of Non-Applicability (NONA) |
|---|---|---|
| Who qualifies | Listed SIC code with industrial stormwater discharge | Listed SIC code, with no exposure of industrial activities or operations to rainfall |
| What you submit in SMARTS | NOI, site map, SWPPP | NEC meeting 11 requirements, plus a site map |
| Ongoing obligations | Monitoring plan, minimum BMPs, sampling, annual report, exceedance response | Annual NEC coverage, $200 per year as of the 2015 permit |
Two cautions apply. The NEC route only works if nothing industrial sits in the rain; a yard with industrial materials or activities exposed to rainfall will not qualify. And everything filed under the IGP is certified electronically, with annual reports, site maps and SWPPPs publicly available, so write them as documents an outsider will read.
What full coverage requires
An NOI puts you under the permit's technology standards: Best Available Technology Economically Achievable (BAT) and Best Conventional Pollutant Control Technology (BCT). You meet them through a Stormwater Pollution Prevention Plan and a monitoring plan. Your SWPPP maps where pollutants come from on your site and lays out the BMPs you use to stop dry-weather flows and cut pollutant loads in storm discharges.
The 1997 permit only suggested BMPs. The current one requires a minimum set:
- good housekeeping
- preventive maintenance
- spill and leak prevention and response
- material handling and waste management
- erosion and sediment controls
- an employee training program
- quality assurance and record keeping
Plastics facilities must also set BMPs for preproduction material.
Sampling is four stormwater effluent events a year, up from two, with samples taken from each drainage area on the site. Every drainage area you add multiplies the samples, lab work and field time at each event, so plan staffing for storms before the wet season starts. Results that exceed a Numeric Action Level (NAL) start the response process.
Responding to a Numeric Action Level exceedance
When sample results exceed a Numeric Action Level, the IGP requires a response action, and a facility can be placed in Exceedance Response Action (ERA) Level 1 status. These are the California steps that follow, which differ from the federal MSGP corrective-action sequence you may know from other states.
| Step | California IGP |
|---|---|
| Trigger | NAL exceedance |
| Reporting clock | Sampling results submitted in SMARTS within 30 days of receiving lab results |
| Professional required | Qualified Industrial Stormwater Practitioner (QISP) prepares the Level 1 ERA Report from the Level 1 ERA Evaluation; the report is submitted and certified in SMARTS |
| SWPPP changes | Significant revisions, including BMPs added under Level 1 or 2, certified in SMARTS within 30 days |
A QISP is also required during the first permit year for new permittees that discharge directly to impaired water bodies. Those facilities face extra scrutiny because the receiving water is already impaired, and where a TMDL has been set, its allocations flow down into permits. If your facility drains to a water impaired for bacteria, our guide to how bacteria TMDL allocations become permit duties for MS4 permit holders shows how that allocation reaches the storm sewer system you may discharge into.
For the federal-side steps, see what MSGP Level 1 corrective action requires.
When minimum BMPs are not enough
Beyond the required minimums, the IGP treats advanced BMPs such as treatment as something you may need once pollutants show up in your samples. Before you add treatment, check whether the NAL parameter you exceeded was reported as a total or dissolved value. If it was total zinc or copper, arrange with your lab to collect and filter a separate sample for dissolved metals at the next sampling event so you know what you are treating.
If it is particulate, such as TSS or metals bound to sediment, go back to housekeeping, sweeping and sediment control. If it is dissolved, sediment controls do little to move the number. Dissolved zinc, copper, lead, arsenic and phosphorus, as well as bacteria and oil and grease that persist after source control, point to a treatment BMP matched to that pollutant:
- Dissolved metals and phosphorus: Smart Sponge® HM, built for the dissolved share of zinc, copper, lead, arsenic and selenium, plus phosphorus.
- Oil, grease and hydrocarbons, including fuel sheen: standard Smart Sponge®, a hydrophobic media that attracts oil and holds it as a stable solid rather than releasing it under flow.
- E. coli and coliform: Smart Sponge® Plus, an antimicrobial media.
When one drainage area carries more than one class, such as oil and dissolved metals, media can be combined in a single system.
Format is a separate choice. If your site already has inlets, an Ultra Urban® Filter insert is fabricated to fit an existing catch basin, installing without excavation, pumps or power. Before ordering an insert, confirm what the structure actually is; why the drop inlet versus catch basin distinction matters for your stormwater permit walks through it. Where flow concentrates at one discharge point, a pumped Smart Skid or an Abtech vessel can hold media in that flow path instead; unlike inserts, a skid needs power.
We start with a site assessment that looks at what is in your water, how much flows, where treatment can physically fit, what your discharge needs to hit and how crews will reach it. For larger applications we can add column testing on a sample of your own water and then a pilot. Because results depend on your site's water, that testing shows what a medium will do before you commit to it in the SWPPP. Your QISP can use those records to support the added BMPs in your revised SWPPP, which is certified in SMARTS within 30 days of significant revisions. Schedule a site assessment with us to start, and once inserts are in, our guide to setting catch basin insert cleaning schedules covers the maintenance log that supports a BMP during inspection.