No Exposure Certification: Requirements, Filing, and Recertification

A No Exposure Certification is a filing that lets an industrial facility skip the full National Pollutant Discharge Elimination System (NPDES) stormwater permit, provided every industrial material and activity at the site is sheltered from rain, snow, snowmelt, and runoff. It is a conditional exclusion under 40 CFR 122.26(g), and it eliminates the monitoring, sampling, and reporting that come with a standard industrial stormwater permit.¹ You keep it only as long as the no-exposure conditions hold, and you have to recertify every five years.

Who Qualifies

The standard is demanding but simple to state: every industrial material and activity has to be under a storm-resistant shelter that prevents contact with precipitation. Raw materials, machinery, intermediate products, waste, loading areas, and material-handling equipment all need to be inside a building or under a roof. If rain can reach it and it is tied to your industrial operations, that is exposure.¹

The exclusion is facility-wide. You cannot shelter part of the site, claim no exposure at those outfalls, and leave the rest uncovered. Either the whole facility qualifies or none of it does.

Construction sites are not eligible. Discharges from construction activity disturbing five or more acres fall under a separate permitting program.²

What Can Still Stay Outside

The regulation carves out a few narrow categories that do not need a permanent roof:

Drums, barrels, tanks, and similar containers that are tightly sealed, not deteriorated, and not leaking, with no open taps or valves.
Adequately maintained vehicles used for material handling, such as company trucks and forklifts, provided they are not leaking fluids or tracking industrial materials.
Final products designed for outdoor use, like new vehicles on a dealer lot, where rain contact does not release pollutants.

Inspectors read these literally. One cracked drum, a forklift with a hydraulic leak, or a container with an open valve is enough to disqualify the site.¹

The 11-Question Checklist

The certification itself, NPDES Form 3510-11, is built around 11 yes/no questions about exposure. A single “yes” disqualifies you.³ The items cover:

Industrial machinery or equipment used, stored, or cleaned outdoors, or residuals from those activities.
Materials or residuals on the ground or in stormwater inlets from spills or leaks.
Materials or products left over from past industrial activity.
Material-handling equipment other than adequately maintained vehicles.
Materials exposed during loading, unloading, or transport.
Products stored outdoors, other than final products designed for outdoor use.
Materials in open, deteriorated, or leaking drums, barrels, or tanks.
Materials on roads or rail lines you own or maintain.
Waste that is not in covered, non-leaking containers such as dumpsters.
Any outdoor application or disposal of process wastewater.
Particulate matter or visible residuals from roof stacks or vents showing up in stormwater outflow.

The questions cover conditions that exist now or could foreseeably exist, so seasonal operations and planned changes count. Walk the property before you answer. A wrong answer is not a clerical problem; it leaves the facility discharging without a permit.

Information and Signature

Along with the checklist, the form asks for the legal name of the business, the facility address with county and latitude/longitude, contact information for the responsible official, and your Standard Industrial Classification (SIC) or North American Industry Classification System (NAICS) code.¹

Signature authority is defined in 40 CFR 122.22. For businesses, that generally means a responsible corporate officer, a general partner, or a principal executive. For government facilities, a ranking elected official or principal executive. This is not something to hand to a site maintenance worker.

How to File

As of December 21, 2025, no exposure certifications filed under federal jurisdiction must be submitted electronically through EPA’s NPDES eReporting Tool (NeT-MSGP), reached through the Central Data Exchange.⁴ The person with signing authority creates a CDX account, completes the smart form, and submits it online. After submission you can download a PDF and view your submission history in the portal.

Most states run their own authorized NPDES programs, so your filing may go to a state environmental agency rather than EPA. State programs sometimes use their own forms and portals, and some charge a processing fee while others do not. Confirm the correct route with your state permitting authority before filing.

If your facility discharges into a municipal separate storm sewer system (MS4), you may also need to give a copy of the certification to the MS4 operator on request and allow inspection.¹

Keeping the Exclusion Valid

Recertify Every Five Years

You must submit a new certification to the permitting authority at least once every five years.² Miss the deadline and the exclusion lapses, which turns any ongoing stormwater discharge into an unpermitted one.

Self-Inspections and Records

EPA does not require a set inspection frequency, but its guidance recommends that a designated person who knows the site regularly walks it to confirm shelters are intact, containers are sealed, and nothing has migrated outdoors.⁵ Quarterly inspections are common; higher-risk sites often go monthly. Keep the logs on-site. NPDES compliance guidance calls for a minimum three-year retention period for facility records.⁶ Record the date, the inspector, the areas checked, and what was found.

The Permitting Authority Can Override

Even with a valid certification on file, the permitting authority can revoke the exclusion and require a full permit if it decides the discharge causes or could reasonably cause a water quality violation. This is discretionary, and the facility has no automatic right of contest beyond standard administrative procedures.¹

When Conditions Change

A facility expansion, equipment change, or shift in operations that puts industrial materials in the path of precipitation voids the exclusion immediately. Once exposure exists, the discharge is subject to enforcement as an unpermitted release.¹

If you know exposure is coming, apply for permit coverage first. Moving to the Multi-Sector General Permit (MSGP) requires developing a Stormwater Pollution Prevention Plan (SWPPP) and making it publicly available, submitting a Notice of Intent through NeT-MSGP, and waiting out a 30-day review period before discharge authorization takes effect.⁷ Waiting until materials are already exposed to begin that process leaves the facility unpermitted for at least a month.

Ownership and Operator Changes

A No Exposure Certification is non-transferable. When a new operator takes over, the previous operator’s certification does not carry across; the new operator has to file its own to claim the exclusion.⁵ Any gap between the old certification and the new one is a gap without an exclusion, during which the facility technically needs permit coverage. If you are acquiring a site that operates under a no-exposure certification, put the new filing on the closing timeline.

Penalties for Getting It Wrong

Discharging stormwater without a permit or a valid exclusion violates the Clean Water Act. Civil penalties can reach $25,000 per day of violation under the statute, and inflation adjustments have pushed the effective maximum higher.⁸

Criminal exposure turns on intent. Negligent violations carry fines between $2,500 and $25,000 per day, up to a year in prison, or both, with a repeat conviction doubling the caps to $50,000 per day and two years. Knowing violations run from $5,000 to $50,000 per day, up to three years, or both, with a repeat conviction reaching $100,000 per day and six years.⁸ Signing a certification while knowing materials are exposed is the kind of conduct that fits the knowing-violation tier. The cost of building a shelter, or of getting proper permit coverage, is small next to that.

1
eCFR. 40 CFR 122.26 – Storm Water Discharges
2
U.S. Environmental Protection Agency. Stormwater Discharges from Industrial Activities – Conditional No Exposure Exclusion
3
U.S. Environmental Protection Agency. 2021 MSGP Appendix K – No Exposure Certification NEC Form
4
U.S. Environmental Protection Agency. Stormwater Discharges from Industrial Activities – Electronic Reporting
5
U.S. Environmental Protection Agency. Guidance Manual for Conditional Exclusion from Storm Water Permitting Based on No Exposure
6
Environmental Protection Agency. NPDES Compliance Inspection Manual – Chapter 3
7
Environmental Protection Agency (EPA). Proposed 2026 Multi-Sector General Permit MSGP Fact Sheet
8
Office of the Law Revision Counsel. 33 USC 1319 – Enforcement