The MassDEP / EPA NPDES Industrial Stormwater Notice of Intent (NOI) is the form a Massachusetts industrial facility files to get legal permission to let rain that touches its industrial areas flow into a lake, river, or storm drain. In Massachusetts, the U.S. Environmental Protection Agency (EPA) Region 1 — not MassDEP — runs this federal program, and the NOI is filed under the 2021 Multi-Sector General Permit (MSGP). The form itself lives in Appendix G of that permit, and you submit it online through EPA’s NPDES eReporting Tool (NeT-MSGP).
Getting this form wrong is not a small paperwork problem. A Massachusetts abrasives maker in North Grafton was hit with a proposed $19,688 penalty in January 2026 for MSGP failures, and Clean Water Act fines can climb far higher per day for an unpermitted discharge. Around 2,400 facilities nationwide hold MSGP coverage, and a single missed field on the NOI can leave a facility discharging illegally without knowing it.
Here is what you will learn in this guide:
- 📋 What the NOI is, who must file it, and the law that forces you to
- 🗂️ Every document and code you need to gather before you open the form
- 🖊️ A line-by-line walkthrough of each NOI section with sample entries
- 🏭 Three full filled-out examples for real Massachusetts facility types
- ⚠️ The field-level mistakes that trigger holds, rejections, and fines
Important timing note: The 2021 MSGP expired at 11:59 p.m. on February 28, 2026, and EPA administratively continued it. Facilities already covered stay covered, but new facilities cannot submit an NOI until EPA issues the next permit. This guide explains the form and that special status so you know exactly where you stand.
What the Form Is and Who Must File It
The Notice of Intent is your formal request to be covered under EPA’s general permit for stormwater that runs off industrial sites. Instead of writing a custom permit for every factory, EPA wrote one big “general” permit — the 2021 MSGP — and your NOI signs your facility up under it. The form tells EPA who you are, where you discharge, what kind of industry you run, and that you have a written plan to keep pollution out of the water.
You must file an NOI if your facility falls into one of the 29 industrial sectors listed in the permit and has stormwater that touches industrial materials or activities, then flows off-site to a “water of the United States.” This includes metal fabricators, scrap and auto salvage yards, landfills, transportation maintenance yards, chemical plants, food processors, and many more. The full match between your business and a sector is set by your Standard Industrial Classification (SIC) code, found in Appendix N of the permit.
The form deconstructs into five connected parts: the purpose (authorize a stormwater discharge), the agency that receives it (EPA Region 1 in Boston, not MassDEP), the statute that requires it (the Clean Water Act, 33 U.S.C. § 1311 and EPA’s rules at 40 CFR 122), the deadline (at least 30 days before a new discharge), and the penalty for skipping it (an unpermitted discharge violation under the Clean Water Act). Each part leans on the next: the statute creates the duty, the permit offers an easy way to meet it, the NOI claims that coverage, and missing the deadline drops you back into illegal-discharge territory.
A quick word on the “MassDEP” confusion. Many filers search for a MassDEP industrial stormwater form because the state agency posts a helpful WM 15 NOI explainer page. But for industrial stormwater, EPA holds the NPDES authority in Massachusetts, so the actual form and filing portal are federal. MassDEP plays a supporting role through state water-quality certification under Clean Water Act Section 401.
Before You Start: Documents and Information You Need
Open the NOI only after you have everything below in front of you. The NeT system times out, and a half-finished NOI with a wrong code is worse than no NOI at all. Gather these items first:
- Your CDX account login. You file the NOI inside EPA’s Central Data Exchange. Without a verified CDX/NeT account, you cannot even open the form, and account approval can take a few days.
- Facility name and physical address. EPA ties your permit and public record to this exact address, and a wrong address sends inspectors and public notices to the wrong place.
- Operator legal name and mailing address. This is the company or person legally responsible; a mismatch here can make your certification invalid.
- Your SIC code (and primary industrial activity). This sets your sector and your monitoring rules, and the wrong code can place you under the wrong pollutant limits.
- Receiving water name. You must name the first water your stormwater reaches, because impaired waters trigger extra monitoring under Part 4 of the permit.
- Latitude and longitude of your discharge points. EPA maps every outfall, and bad coordinates can flag your NOI for review.
- Your completed SWPPP. The Stormwater Pollution Prevention Plan must be written and signed before you file, since the NOI certifies it already exists; filing without one is a false certification.
- Endangered species and historic property screening results. You must document how you meet the Appendix E (species) and Appendix F (historic) eligibility criteria, or EPA cannot authorize coverage.
- Number and description of outfalls. Each point where stormwater leaves your site needs its own listing so monitoring is tied to the right spot.
- Name and title of the certifying official. Only a “responsible corporate officer” or equivalent under 40 CFR 122.22 may sign, and a signature from the wrong person voids the filing.
If any one of these is missing, stop and get it. A missing SWPPP or a guessed SIC code is the single fastest way to turn a routine filing into an enforcement file.
Where to Get the Form and How to Access It
The official NOI form lives as Appendix G of the 2021 MSGP, which you can read as a PDF on EPA’s MSGP page. Read the PDF to plan your answers, but you do not mail this paper form in normal times. Almost all filers must submit the NOI electronically.
You file the live NOI through the NeT-MSGP electronic system, which sits inside EPA’s Central Data Exchange (CDX). First you create a CDX account, then you add the “NeT: MSGP” program service, then you request a role for your facility. Once EPA verifies your identity, the blank NOI opens as a guided web form that mirrors Appendix G section by section.
Paper filing is rare and only allowed with an approved electronic reporting waiver. If you have no reliable internet or a religious objection, you may request a waiver from EPA Region 1; if granted, you mail the Appendix G paper form to the address EPA provides. For everyone else, the rule under 40 CFR Part 127 is electronic-only.
The version matters. This guide covers the 2021 MSGP, effective March 1, 2021, with a minor modification effective September 29, 2021. Confirm you are looking at the September 2021 modified Appendix G before you start, because earlier drafts have different field layouts.
Step-by-Step: How to Fill Out the MSGP Notice of Intent Line by Line
The NOI is organized into numbered sections inside NeT. Below is each major section as its own walkthrough. Follow them in the order the form presents them.
Section 1: Operator Information
What it asks in plain English. This section asks who legally runs the facility — the person or company that controls how the site operates and is responsible for following the permit.
How to answer it. Enter the operator’s full legal name, mailing address, and a contact person with phone and email. Type the legal entity name exactly as it appears on your business registration, with no nicknames or “doing business as” shortcuts in the legal-name box.
A specific example answer. Bay State Metalworks LLC enters its legal name as Bay State Metalworks LLC, its mailing address as 44 Industrial Way, Worcester, MA 01604, and lists plant manager Tom Reyes as the contact.
A nuance or edge case. What if a property owner and a separate company run the site? The “operator” is whoever has day-to-day operational control of the industrial activity, not always the landowner. If two entities share control, both may need coverage.
A common mistake on this field and its direct consequence. Filers often enter the parent corporation when a subsidiary actually runs the plant. That mismatch can make EPA hold the NOI because the certifying signature will not match the named operator.
A misconception about this field. Many think the “operator” must be the building owner. It is not — it is the party that controls the industrial operations and the pollution-prevention decisions on the ground.
Section 2: Facility / Site Information
What it asks in plain English. This section asks where the facility physically sits and how to find it, separate from your mailing address.
How to answer it. Enter the facility name, the street address, city, state, ZIP, and county. Use the real physical location, even if it has no normal street number, and never substitute a P.O. box here.
A specific example answer. Pioneer Auto Salvage enters its facility name and the site address 210 Riverside Road, Springfield, MA 01089, Hampden County.
A nuance or edge case. What if your site has no street address? Enter a clear description and rely on the latitude and longitude fields so EPA can still map you.
A common mistake on this field and its direct consequence. Using the mailing address or a P.O. box as the facility address sends inspectors to the wrong spot and can flag your record as inaccurate.
A misconception about this field. People assume the facility address and operator address must match. They often differ, and EPA expects the physical site here.
Section 3: Latitude, Longitude, and Mapping
What it asks in plain English. This asks for the exact map coordinates of your facility and discharge points.
How to answer it. Enter latitude and longitude in decimal degrees, and pick the method used (such as the NeT map tool or GPS). Use the built-in mapping tool in NeT to drop a pin, which fills the coordinates for you.
A specific example answer. Pioneer Auto Salvage drops a pin on its yard and the tool fills in 42.1015 latitude and -72.5898 longitude.
A nuance or edge case. What if you have several outfalls spread across a large site? Map the facility center for the main coordinates, then list each outfall location later in the discharge section.
A common mistake on this field and its direct consequence. Typing coordinates from a phone with the sign reversed (positive instead of negative longitude) places your site in the wrong hemisphere and triggers a data-quality flag.
A misconception about this field. Filers think coordinates are optional decoration. EPA uses them to tie your discharge to a specific watershed and impaired-water list, so they directly affect your monitoring duties.
Section 4: Industrial Activity and SIC / NAICS Code
What it asks in plain English. This asks what kind of industry you run, expressed through your SIC code, which then sets your permit “sector.”
How to answer it. Enter the primary SIC code that matches your main industrial activity, then confirm the sector NeT assigns. Match your code against Appendix N before you type it, and add secondary codes if you run more than one covered activity.
A specific example answer. Bay State Metalworks LLC enters SIC 3444 (sheet metal work), which places it in Sector AA – Fabricated Metal Products.
A nuance or edge case. What if your site fits two sectors, such as metal fabrication plus a vehicle maintenance area? You list each applicable sector, and you must meet the monitoring rules for all of them.
A common mistake on this field and its direct consequence. Choosing a “close enough” SIC code puts you under the wrong sector’s benchmark monitoring, so you may sample for the wrong pollutants and fail an inspection.
A misconception about this field. Many believe the SIC code is just a label. It is the engine of the whole permit — it decides your effluent benchmarks, your inspection schedule, and your sector-specific limits in Part 8.
Section 5: Receiving Waters and Impaired Waters
What it asks in plain English. This asks which water body your stormwater reaches first and whether that water is already polluted (impaired) or has a cleanup plan (TMDL).
How to answer it. Name the receiving water and state whether it appears on the state’s impaired-waters list. Check the Massachusetts Integrated List and the permit’s impaired-waters tools, because impaired status adds Part 4 monitoring.
A specific example answer. Pioneer Auto Salvage names the Connecticut River as its receiving water and notes it is impaired for several pollutants.
A nuance or edge case. What if your stormwater enters a municipal storm sewer (MS4) before reaching a river? You still name the ultimate receiving water, and you note the storm sewer as the conveyance.
A common mistake on this field and its direct consequence. Naming a storm drain as the receiving water instead of the river it feeds hides an impaired-water trigger, which can leave you under-monitoring and out of compliance.
A misconception about this field. Filers think only direct riverfront sites have a receiving water. Even a site miles inland has one — the first natural water its runoff eventually reaches.
Section 6: Endangered Species (Appendix E) Eligibility
What it asks in plain English. This asks how your discharge avoids harming federally protected species and their habitat.
How to answer it. Select which of the Appendix E eligibility criteria (A through F) you meet and document your basis. Run the screening using EPA’s species tool and keep the printout with your records.
A specific example answer. Bay State Metalworks LLC selects Criterion A, certifying no listed species or critical habitat are in its action area based on the screening map.
A nuance or edge case. What if listed species are present? You may need to meet Criterion C and adopt measures, sometimes after coordinating with the U.S. Fish and Wildlife Service.
A common mistake on this field and its direct consequence. Picking Criterion A without actually running the screening is a false certification that can void your coverage and expose you to enforcement.
A misconception about this field. People assume city industrial sites have no species concerns. Urban rivers can still host listed species, so the screening is required for every facility.
Section 7: Historic Properties (Appendix F) Eligibility
What it asks in plain English. This asks whether your stormwater controls could disturb historic or archaeological sites.
How to answer it. Answer the Appendix F screening questions and select the criterion you meet. If you are not building new ground-disturbing controls, you usually qualify under the simplest criterion.
A specific example answer. Green Mountain Transit Yard answers that it is installing no new subsurface controls and selects the criterion confirming no historic-property effect.
A nuance or edge case. What if you plan to dig to install a new infiltration basin? Ground disturbance can trigger a State Historic Preservation Office contact before you qualify.
A common mistake on this field and its direct consequence. Skipping this section because the site “is just a parking lot” leaves the NOI incomplete and blocks authorization.
A misconception about this field. Filers think historic review applies only to old buildings. It also covers buried archaeological resources that earth-moving controls could disturb.
Section 8: Stormwater Pollution Prevention Plan (SWPPP) Certification
What it asks in plain English. This asks you to confirm that your written SWPPP is complete and in place before you file.
How to answer it. Check the box certifying the SWPPP has been prepared in line with Part 5 of the permit. Confirm the plan is signed and on-site first, because this box is a legal statement that it already exists.
A specific example answer. Bay State Metalworks LLC checks the SWPPP certification box after its environmental consultant finalizes and signs the plan dated 03/10/2026.
A nuance or edge case. What if your SWPPP is drafted but not yet signed? It does not count — the certification requires a finalized plan, so finish it first.
A common mistake on this field and its direct consequence. Checking the box while the SWPPP is still a draft is a false certification under penalty of law and a frequent enforcement finding.
A misconception about this field. Many think the SWPPP gets uploaded with the NOI. It does not — you keep it on-site and make it available on request, but you must certify it exists.
Section 9: Discharge Points / Outfalls
What it asks in plain English. This asks you to list every point where stormwater leaves your site, each with its own ID.
How to answer it. Add each outfall with a unique identifier and its receiving water. Walk your site map and confirm every pipe, ditch, and swale that carries runoff off the property.
A specific example answer. Pioneer Auto Salvage lists Outfall 001 (north ditch to the Connecticut River) and Outfall 002 (south storm drain).
A nuance or edge case. What if two outfalls discharge to the same water? List them separately anyway, because monitoring is tracked per outfall.
A common mistake on this field and its direct consequence. Listing only one outfall when the site has three means you monitor one-third of your discharge and under-report, a clear permit violation.
A misconception about this field. Filers think only piped outlets count. Sheet flow, ditches, and swales that leave the property are outfalls too.
Section 10: Certification and Signature
What it asks in plain English. This is where a responsible official swears the whole NOI is true under penalty of law and electronically signs it.
How to answer it. The signer must be a responsible corporate officer or duly authorized representative under 40 CFR 122.22, using their own CDX credentials. Read the certification language, then sign electronically with the verified account.
A specific example answer. Tom Reyes, plant manager and authorized representative, signs the Bay State Metalworks LLC NOI electronically on 03/15/2026.
A nuance or edge case. What if a consultant prepared the NOI? The consultant may enter data, but the responsible official — not the consultant — must apply the certifying signature.
A common mistake on this field and its direct consequence. Letting an office assistant or consultant sign invalidates the certification and can make the entire coverage void.
A misconception about this field. People think an electronic signature is informal. It carries the same legal weight as an ink signature, including false-statement liability under the Clean Water Act.
Three Filled-Out Examples Using Real Scenarios
Below are three Massachusetts facility types walked through the NOI from start to finish. Each table shows the most important entries.
Scenario 1: Bay State Metalworks LLC — Metal Fabrication Shop (Sector AA)
Tom Reyes runs a sheet-metal shop in Worcester with outdoor scrap storage exposed to rain.
| Form Section | What Bay State Metalworks Enters |
|---|---|
| Operator legal name | Bay State Metalworks LLC |
| Facility address | 44 Industrial Way, Worcester, MA 01604 |
| County | Worcester |
| Latitude / Longitude | 42.2626 / -71.8023 |
| SIC code / Sector | 3444 / Sector AA – Fabricated Metal |
| Receiving water | Blackstone River (impaired) |
| Endangered species criterion | Criterion A – none present |
| SWPPP certification | Yes, signed 03/10/2026 |
| Outfalls | Outfall 001 – yard swale |
| Certifying signer | Tom Reyes, Plant Manager, 03/15/2026 |
Scenario 2: Pioneer Auto Salvage — Scrap and Salvage Yard (Sector N / M)
Maria Santos operates an auto recycling yard in Springfield with vehicle fluids and crushed cars stored outside.
| Form Section | What Pioneer Auto Salvage Enters |
|---|---|
| Operator legal name | Pioneer Auto Salvage Inc. |
| Facility address | 210 Riverside Road, Springfield, MA 01089 |
| County | Hampden |
| Latitude / Longitude | 42.1015 / -72.5898 |
| SIC code / Sector | 5015 / Sector N – Scrap Recycling |
| Receiving water | Connecticut River (impaired) |
| Endangered species criterion | Criterion C – measures adopted |
| SWPPP certification | Yes, signed 02/20/2026 |
| Outfalls | Outfall 001 north ditch; Outfall 002 south drain |
| Certifying signer | Maria Santos, President, 02/25/2026 |
Scenario 3: Green Mountain Transit Yard — Vehicle Maintenance / Transportation (Sector P)
David Chen manages a bus and truck maintenance depot in Lowell with fueling and washing areas.
| Form Section | What Green Mountain Transit Enters |
|---|---|
| Operator legal name | Green Mountain Transit Authority |
| Facility address | 88 Depot Street, Lowell, MA 01852 |
| County | Middlesex |
| Latitude / Longitude | 42.6334 / -71.3162 |
| SIC code / Sector | 4173 / Sector P – Land Transportation |
| Receiving water | Merrimack River |
| Historic property criterion | No new ground disturbance |
| SWPPP certification | Yes, signed 01/15/2026 |
| Outfalls | Outfall 001 wash-bay drain to MS4 |
| Certifying signer | David Chen, Facilities Director, 01/20/2026 |
How to File the Completed Form
In normal permit periods you file the NOI through one main channel, with a rare paper backup.
- Online through NeT-MSGP (standard channel). Log in at the NeT-MSGP portal inside CDX, complete each section, and apply your electronic signature. There is no filing fee. Payment method: none. Processing time: coverage is generally authorized 30 days after a complete NOI for new dischargers, or as set in Part 1.3 of the permit. Proof of filing: save the confirmation email and the PDF copy NeT generates with your tracking number.
- Paper, by mail (waiver only). If EPA grants an electronic-reporting waiver, mail the signed Appendix G form to U.S. EPA Region 1, 5 Post Office Square, Suite 100, Boston, MA 02109-3912. Fee: none. Payment method: none. Processing time: longer than electronic, since staff must key it in. Proof of filing: use certified mail and keep the return receipt.
Right now, the special administrative-continuance rules change who can file at all. EPA’s continuance guidance says existing covered facilities do not refile, and new facilities cannot file an NOI until the next MSGP issues. New operators may instead follow EPA’s No Action Assurance memorandum by emailing the Appendix G form to msgp@epa.gov, which is not the same as permit coverage.
After EPA issues the next MSGP, existing operators will have 90 days from its effective date to submit a fresh NOI in NeT-MSGP to move onto the new permit. Watch for EPA’s notification, because that 90-day window is firm.
What Happens After You File
Once you submit a complete NOI in normal times, NeT records it and your facility status updates in the system. For new dischargers, authorization to discharge generally begins 30 days after EPA receives the complete NOI, unless EPA contacts you with questions or denies coverage. You should download and keep the dated confirmation.
EPA may review the NOI and request corrections, especially if your SIC code, coordinates, or eligibility certifications look off. If EPA finds your facility ineligible — for example, because of unresolved endangered-species concerns — it can require you to seek an individual permit instead. Your obligation to monitor, inspect, and report under the permit starts as soon as coverage begins.
Under the current administrative continuance, existing facilities now show a status of “Admin. Continued” in NeT, and the “Change NOI” function is disabled, so you keep any update records on-site. You must keep complying with all monitoring and reporting duties during the continuance, including quarterly visual assessments and the annual report due January 30.
Mistakes to Avoid When Filling Out the Form
- Filing without a finished SWPPP — your certification becomes a false statement subject to penalty.
- Choosing the wrong SIC code — you fall under the wrong sector’s monitoring and can fail inspections.
- Entering a P.O. box as the facility address — inspectors and notices go to the wrong place.
- Reversing the sign on longitude — your site maps to the wrong location and triggers a data flag.
- Naming a storm drain instead of the true receiving water — you miss an impaired-water trigger and under-monitor.
- Skipping the endangered-species screening — your eligibility certification is invalid and coverage can be voided.
- Listing only one outfall when several exist — you under-report and violate monitoring duties.
- Letting a consultant apply the certifying signature — the certification is invalid and coverage can fail.
- Using the parent company as operator when a subsidiary runs the site — the signature and operator name mismatch causes a hold.
- Assuming coverage starts immediately — discharging before the 30-day authorization is an unpermitted discharge.
- Ignoring the impaired-waters monitoring in Part 4 — you sample for the wrong parameters and miss benchmarks.
- New facilities trying to file during the administrative continuance — no coverage results, leaving discharges unpermitted.
Do’s and Don’ts
Do: – Do finalize and sign your SWPPP before opening the NOI, because the form certifies it already exists. – Do verify your SIC code against Appendix N, because it controls your entire monitoring program. – Do use the NeT map tool for coordinates, because it prevents sign and typo errors. – Do confirm your receiving water’s impaired status, because it adds required monitoring. – Do save the NeT confirmation PDF, because it is your proof of filing. – Do have the responsible official sign personally, because only their signature is valid.
Don’t: – Don’t guess a “close enough” SIC code, because the wrong sector means the wrong limits. – Don’t list a P.O. box as the facility location, because EPA needs the physical site. – Don’t certify eligibility you have not screened, because false certification invites enforcement. – Don’t discharge before authorization, because the 30-day wait is mandatory for new dischargers. – Don’t let staff or consultants sign for the official, because that voids the certification. – Don’t assume MassDEP processes this form, because EPA Region 1 holds the authority.
Pros and Cons of Filing on Your Own vs. With Help
| Filing the NOI Yourself | Filing With a Consultant or Attorney |
|---|---|
| Saves money, since there is no filing fee and no professional bill. | Costs more, but spreads the risk of an expensive error. |
| Builds in-house knowledge, so you understand your own permit duties. | Brings expertise, so SIC codes and species screening are done right. |
| Faster for a simple single-outfall site you know well. | Faster for complex multi-sector or multi-outfall sites. |
| Full control over your data and timing. | Less day-to-day control, but professional accountability. |
| Risk of a field-level mistake that triggers a hold or fine. | Lower error risk, since pros file these routinely. |
FAQs
Do I file the industrial stormwater NOI with MassDEP?
No. In Massachusetts, EPA Region 1 holds NPDES authority for industrial stormwater, so you file the NOI with EPA through NeT-MSGP, not MassDEP.
Is there a fee to submit the NOI?
No. EPA charges no fee to file the MSGP Notice of Intent, whether you submit it electronically or, with a waiver, on paper.
Can a new facility file an NOI right now?
No. Because the 2021 MSGP was administratively continued after February 28, 2026, new facilities cannot get coverage until EPA issues a new permit.
Do existing covered facilities need to refile after the permit expired?
No. EPA says covered facilities automatically stay covered under the administratively continued permit and should not resubmit an NOI.
Do I write my SIC code or my NAICS code in the activity box?
Yes. Enter the SIC code that matches your primary industrial activity; the form also accepts NAICS, but SIC drives your sector assignment under Appendix N.
In the receiving water field, do I name the storm drain or the river?
No. Do not name the storm drain; enter the natural water your runoff ultimately reaches, since impaired-water status depends on it.
Do I upload my SWPPP with the NOI?
No. You keep the SWPPP on-site and make it available on request; the NOI only certifies that the plan already exists.
In the operator box, do I list the building owner or the company running the site?
No. List the operator with day-to-day control of the industrial activity, which is often not the building owner.
Can my environmental consultant sign the certification for me?
No. Only a responsible official under 40 CFR 122.22 may sign; the consultant may enter data but cannot certify.
Does coverage start the moment I hit submit?
No. For new dischargers, authorization generally begins 30 days after EPA receives a complete NOI, not at submission.
Do I need to run an endangered-species screening for an urban site?
Yes. Every facility must complete the Appendix E screening, because even urban waters can host federally listed species.
Is the electronic signature in NeT legally binding?
Yes. The CDX electronic signature carries the same legal weight as ink, including liability for false statements under the Clean Water Act.
Related reading
- How to Fill Out Florida DEP NPDES Industrial Stormwater Permit + FAQs
- How to Fill Out the MassDEP / EPA NPDES Construction Stormwater Permit (With Examples) + FAQs
- How to Fill Out the MassDEP NPDES Construction Stormwater Permit (With Examples) + FAQs
- How to Fill Out MassDEP NPDES Industrial Stormwater (w/Examples) + FAQs
- How to Fill Out the Ohio EPA NPDES Industrial Stormwater Permit (OHR000007) + FAQs
- How to Fill Out the Massachusetts Chapter 21E Release Notification (BWSC-103)
- How to Fill Out the Washington Ecology Water Quality Modification Permit + FAQs