NPDES Application Form 2F (EPA Form 3510-2F) is the federal form a facility files to get permission to discharge stormwater linked to industrial activity into a lake, river, stream, or other water of the United States. You file it under the Clean Water Act with the agency that runs the National Pollutant Discharge Elimination System (NPDES) program in your state, or with your EPA Regional Office if your state is not authorized.
This form proves your rain runoff will not dump harmful pollutants into public water. Filing late, leaving out the site drainage map, or skipping the required sampling can stall your permit for months and expose you to fines that reach into the tens of thousands of dollars per day. The current version is the Revised 3-19 form, approved 03/05/19 under OMB Control No. 2040-0004, and you should check the revision date in the form’s footer before you start so you do not use an outdated copy.
More than 100,000 facilities across the country fall under industrial stormwater rules, and EPA’s own application checklist lists the site map and sampling tables as the items applicants most often get wrong. Here is what you will learn:
- 🗺️ How to build a site drainage map that the permit reviewer will accept the first time.
- 🧪 How to collect samples during a “qualifying storm event” so your lab data counts.
- 📋 How to pick the right pollutant tables (A through C) for each of your outfalls.
- 🏭 Three full filled-out examples for a scrap yard, a manufacturer, and a trucking facility.
- ⚠️ The ten mistakes that get Form 2F applications rejected and how to dodge each one.
What the Form Is and Who Must File It
Form 2F is the federal permit application for stormwater discharges associated with industrial activity. You file it together with Form 1, which gives general facility information. The form goes to your NPDES permitting authority, which is the state environmental agency in the 47 states that run their own programs, or the EPA Regional Office in states and territories where EPA still runs the program.
You must file Form 2F if your facility is in one of the eleven categories of “industrial activity” defined at 40 CFR 122.26(b)(14) and you discharge stormwater from that activity through a point source to a water of the United States. These categories include manufacturers, mining sites, landfills, recycling and scrap yards, steam electric plants, transportation facilities with vehicle maintenance, and treatment works. If your runoff mixes with non-stormwater (process wastewater), you also file Form 2C, 2D, or 2E, whichever fits the wastewater type.
The statute behind the form is the Clean Water Act, which bans any pollutant discharge from a point source unless a permit allows it. The deadline matters: existing dischargers must apply at least 180 days before their current permit expires, and new dischargers must apply at least 180 days before they plan to start discharging. The penalty for discharging without a permit can reach civil fines of more than $66,000 per day per violation under EPA’s inflation-adjusted penalty rules, so a missed filing is not a paperwork problem, it is a financial risk.
Many filers think a general permit covers them, so they never touch Form 2F. That is sometimes true, but if your state has no general permit for your sector, or your discharge does not qualify, you must file the individual application on Form 2F instead.
Before You Start: Documents and Information You Need
Gather everything before you open the form. Form 2F asks for measured data and maps that you cannot invent at your desk, and a missing piece is the top reason applications come back marked incomplete. Build this pile first:
- Your EPA Identification Number. You enter it at the top of each page, and the reviewer uses it to match your file. Without it, your pages can get separated and lost.
- Current NPDES permit number (if you have one). This links your renewal to your existing file. Leaving it off a renewal makes the agency open a duplicate record.
- Latitude and longitude of every outfall. The form needs degrees, minutes, and seconds. Guessed coordinates can place your outfall on the wrong waterbody and trigger questions.
- A topographic map (required by Form 1, Item 7.1) showing your facility and the receiving water. You can pull one from the USGS National Map. A missing map stops the review cold.
- A site drainage map showing buildings, paved areas, storage spots, and control measures. This is required by Form 2F, Item 3.1, and it is the single most common attachment failure.
- Lab sampling results from a qualifying storm event, no older than 3 years, using methods approved under 40 CFR 136. Old or non-approved data is rejected outright.
- A list of significant materials stored or handled outdoors in the last 3 years. You need this for the narrative in Item 3. Forgetting a material can later be read as a false statement.
- Records of any leaks or spills of toxic or hazardous pollutants in the last 3 years, with dates, locations, and amounts. Skipping a known spill undercuts your certification.
- A certified lab number for each analysis. The form has a column for it, and a blank column can void the data row.
- The name and title of your authorized signer. Only a person who meets 40 CFR 122.22 can sign. The wrong signer voids the whole application.
Where to Get the Form and How to Access It
The official Form 2F lives on EPA’s NPDES applications page, where you can download the fillable PDF of EPA Form 3510-2F along with its line-by-line instructions. Always pull the form from this EPA page or from your own state agency’s permitting page, because third-party copies may be out of date and missing the current OMB approval.
If your state runs its own NPDES program, your state agency may host its own version of the same federal form, sometimes with a state cover sheet. For example, a California filer works through the State Water Resources Control Board, while an Iowa filer uses the Iowa DNR copy of Form 2F. The content is the same federal form, but the mailing address and any state fee differ, so start at your state agency’s stormwater page to confirm where to send it.
Many states now require electronic submission through a portal because of EPA’s NPDES eReporting Rule. Check whether your authority uses a system like NeT (NPDES eReporting Tool) before you fill out a paper copy, since some agencies will only accept the online version. If you are unsure which channel applies, call your permitting authority before you begin so you do not complete the form in the wrong format.
Step-by-Step: How to Fill Out Form 2F Line by Line
Form 2F is organized into numbered items. Enter your facility name and EPA Identification Number at the top of the first page and on every attachment. Work through the items in order, and complete a separate set of discharge tables for each outfall.
Item 1: Outfall Locations
What it asks. This item asks you to list each outfall that discharges industrial stormwater, with its latitude and longitude and the route the water travels to the first named stream.
How to answer it. Enter one row per outfall. Fill the latitude and longitude in degrees, minutes, and seconds. In the “Route of Flow” box, trace the path in plain words, such as unnamed ditch to Mission Creek to San Francisco Bay.
Example. Greenline Metals lists Outfall 001 at latitude 37° 46’ 12” and longitude 122° 23’ 30”, with a route of flow reading yard swale to storm drain to Islais Creek.
Nuance. If two pipes drain to the same spot but carry different runoff, list them as separate outfalls. Combining them hides where each pollutant comes from.
Common mistake and consequence. Filers often guess coordinates from memory. A wrong coordinate can place your outfall on the wrong receiving water, which forces the reviewer to send the form back for correction and adds weeks to your timeline.
Misconception. Some think a stormwater outfall is only a pipe. An outfall is any point source, including a ditch or channel, so a sheet-flow swale that reaches a stream still counts.
Item 2: Site Drainage Map
What it asks. This item asks you to attach a map of your site that shows how stormwater moves across it and where it leaves through each outfall.
How to answer it. Draw or print a map and label it with your EPA ID number. The map must show topography or drainage area outlines, every intake and outfall, paved areas and buildings, past and present outdoor storage or disposal areas for significant materials, existing control measures, loading and access areas, spots where pesticides or fertilizers are applied, hazardous waste units, injection wells, and any springs or surface waters that receive your discharge.
Example. Greenline Metals attaches a scaled site map that shades the paved scrap-storage yard, marks Outfall 001, draws an arrow to Islais Creek, and circles the covered oil drum rack as a control measure.
Nuance. If your site is large, you may use more than one sheet or an inset, as long as every required feature appears somewhere and the sheets connect clearly.
Common mistake and consequence. The most common failure on the whole form is a map that leaves out outdoor storage areas or control measures. EPA’s checklist flags this directly, and an incomplete map makes the entire application incomplete under 40 CFR 122.21(e).
Misconception. People assume a generic facility blueprint will do. A blueprint that omits drainage flow and storage areas does not meet the map requirement, even if it looks professional.
Item 3: Description of Pollutant Sources
What it asks. This item asks you to describe, for each outfall, how much area drains to it, what materials sit exposed to rain, and what controls you use.
How to answer it. In Item 3.A, give the impervious surface area and the total area drained for each outfall, with units. In Item 3.B, write a narrative of significant materials treated, stored, or disposed in a way that exposed them to stormwater over the last 3 years, including management practices and where pesticides or fertilizers are applied. In Item 3.C, list each outfall’s structural and nonstructural control measures.
Example. Greenline Metals enters Outfall 001 — impervious surface 1.8 acres, total area drained 2.4 acres, then describes scrap steel and crushed auto bodies stored uncovered on pavement, and lists covered drum storage, perimeter berm, and weekly housekeeping sweeps as controls.
Nuance. “Significant materials” is broad. It covers fuels, solvents, plastic pellets, metal products, CERCLA hazardous substances, SARA Title III chemicals, fertilizers, pesticides, and waste like slag, ash, or sludge that rain can carry off.
Common mistake and consequence. Filers report only impervious area and forget the total area drained. Missing the total area means the reviewer cannot judge runoff volume, and the item gets bounced back.
Misconception. Some believe controls must be physical structures. Nonstructural controls such as spill plans, employee training, and inspections count too and should be listed.
Item 4: Non-stormwater Discharges
What it asks. This item asks how you tested or evaluated each outfall for non-stormwater (dry-weather) flows that are not already permitted.
How to answer it. Describe the method you used, such as a smoke test, a fluorometric dye test, or review of accurate plumbing schematics. Give the date of testing and list the on-site drainage points you directly observed during the test. If you find any non-stormwater discharge, you must identify it on an accompanying Form 2, 3, or 4.
Example. Greenline Metals writes dye test performed 04/15/2026 at Outfall 001; observed three floor-drain points; no non-stormwater flow detected.
Nuance. If you do find an unpermitted dry-weather flow, you cannot just note it. You must file the matching Form 2C, 2D, or 2E for that discharge with this application.
Common mistake and consequence. Filers write “none” without describing any test. A bare denial with no method or date fails the certification and can be treated as an unsupported claim.
Misconception. People think a quick visual glance counts as a test. The item expects a defined evaluation method and observed drainage points, not a casual look.
Item 5: Significant Leaks or Spills
What it asks. This item asks for any significant leaks or spills of toxic or hazardous pollutants at the facility in the last 3 years.
How to answer it. Using existing records, list the approximate date and location of each spill or leak and the type and amount of material released. If there were none, state that plainly.
Example. Greenline Metals reports hydraulic oil release, approx. 15 gallons, near baler, 08/2024, cleaned with absorbent and reported to county.
Nuance. “Existing information” means you do not have to launch a new investigation, but you cannot ignore records you already hold.
Common mistake and consequence. Filers omit a known spill to look cleaner. If the agency later finds the record, the omission can be read as a false statement under the signed certification, which carries legal exposure.
Misconception. Some think only reportable-quantity spills belong here. Any significant leak or spill of a toxic or hazardous pollutant belongs in this item, even if it was below a federal reporting threshold.
Item 6: Discharge Information (Tables 6.A through 6.F)
What it asks. This set of tables asks for the measured pollutant levels in your stormwater, sampled during a qualifying storm event, with one full set of tables completed for each outfall.
How to answer it. Report all results as concentration, using units such as mg/l or µg/l. For most pollutants you collect both a grab sample during the first 30 minutes of the storm and a flow-weighted composite from the whole event. Collect grab samples only for pH, temperature, cyanide, total phenols, residual chlorine, oil and grease, volatile organics, and E. coli. Enter maximum and average values, the number of storm events sampled, the source of the pollutant, and the certified laboratory number.
The six sub-tables split up like this: – 6.A — Common pollutants. Required for every outfall. You sample oil and grease, BOD5, COD, TSS, TKN, nitrate plus nitrite, total phosphorus, and pH. – 6.B — Effluent guideline and permit pollutants. Required if an effluent limitations guideline or your existing NPDES permit limits a pollutant in your process wastewater. – 6.C — Table 1 pollutants you know or have reason to believe are present. – 6.D — Table 2 toxic pollutants and total phenols. You must give quantitative data for any expected above 10 µg/L. – 6.E — Table 3 pollutants, including asbestos, that you expect to be present. – 6.F — Storm event data for the event that produced your maximum composite values, including date, duration, total rainfall, hours since the last rain, and flow.
Example. Greenline Metals reports for Outfall 001: TSS maximum 210 mg/l, average 140 mg/l, 1 storm event, source = scrap yard runoff, lab #IA0123, and lists total zinc 0.45 mg/l in Table 6.D.
Nuance. A “qualifying storm event” is rain greater than 0.1 inch that falls at least 72 hours after the last measurable rain. Sampling during a smaller or back-to-back storm makes the data invalid.
Common mistake and consequence. Filers report “non-detect” or “0” instead of the actual numeric value. The rules require the real measured number even below the detection limit, and entering “ND” can get the row rejected. Misplaced decimal points and mismatched units are the other frequent errors EPA’s checklist calls out.
Misconception. Many assume one grab sample covers everything. Most pollutants need both a first-30-minute grab and a full-storm composite, and using only a grab leaves the table incomplete.
Items 10.1 and 10.2: Checklist and Certification
What it asks. The final items ask you to complete the application checklist (Item 10.1) and sign the certification statement (Item 10.2) swearing the information is true.
How to answer it. Check off every attachment you are enclosing in the Item 10.1 checklist. Then have an authorized official sign and date Item 10.2. For a corporation, that is a responsible officer; for a partnership, a general partner; for a sole proprietor, the owner; for a government facility, a ranking elected official or principal executive.
Example. Greenline Metals checks the site map and Tables A through C boxes, and its president Dana Cole signs and dates Item 10.2 as 03/15/2026.
Nuance. A duly authorized representative may sign if a proper written authorization is on file with the agency under 40 CFR 122.22(b).
Common mistake and consequence. An office manager or consultant signs without authority. An unauthorized signature voids the certification, and the agency will not process an uncertified application.
Misconception. People think any company employee can sign. Only the specific officials named in the rule, or an authorized representative on file, may sign Form 2F.
Three Filled-Out Examples Using Real Scenarios
These three scenarios follow common Form 2F filers from start to finish. Each table shows what the named filer enters in the main sections of the form.
Scenario 1: Dana Cole, Metal Scrap and Recycling Yard
| Form Section | What Greenline Metals Enters |
|---|---|
| EPA ID Number | CAD000111222 on every page |
| Item 1: Outfall | Outfall 001, lat 37° 46’ 12”, long 122° 23’ 30” |
| Item 1: Route of flow | yard swale to storm drain to Islais Creek |
| Item 2: Site map | Scaled map showing paved scrap yard, covered drum rack, berm |
| Item 3.A: Area | Impervious 1.8 acres; total drained 2.4 acres |
| Item 3.B: Materials | Uncovered scrap steel and crushed auto bodies |
| Item 4: Non-stormwater | Dye test 04/15/2026; no dry-weather flow found |
| Item 5: Spills | 15-gal hydraulic oil release near baler, 08/2024 |
| Item 6.A: TSS | Max 210 mg/l, avg 140 mg/l, 1 event, lab #CA0123 |
| Item 6.D: Zinc | Total zinc 0.45 mg/l |
| Item 10.2: Signature | Dana Cole, President, 03/15/2026 |
Scenario 2: Marcus Reed, Metal Parts Manufacturer
| Form Section | What Apex Fabrication Enters |
|---|---|
| EPA ID Number | OHD000333444 on every page |
| Item 1: Outfalls | Outfall 001 and Outfall 002 with coordinates |
| Item 2: Site map | Map marking outdoor steel coil storage and roof drains |
| Item 3.A: Area | Outfall 001 impervious 3.1 acres; total 4.0 acres |
| Item 3.B: Materials | Steel coils, cutting oils, plastic pellets stored outdoors |
| Item 3.C: Controls | Covered storage, spill plan, employee training |
| Item 4: Non-stormwater | Schematic review and smoke test, 03/2026 |
| Item 6.A: COD | Max 95 mg/l, avg 60 mg/l, 1 event, lab #OH0456 |
| Item 6.B: Permit pollutant | Total iron 1.2 mg/l per ELG |
| Item 6.D: Lead | Total lead 0.018 mg/l |
| Item 10.2: Signature | Marcus Reed, Plant Manager (authorized rep), 02/20/2026 |
Scenario 3: Aisha Bello, Trucking and Vehicle Maintenance Facility
| Form Section | What Bay City Freight Enters |
|---|---|
| EPA ID Number | CAD000555666 on every page |
| Item 1: Outfall | Outfall 001, route parking lot to MS4 to San Leandro Bay |
| Item 2: Site map | Map showing fueling island, wash bay, maintenance shop |
| Item 3.A: Area | Impervious 5.0 acres; total drained 5.4 acres |
| Item 3.B: Materials | Diesel fuel, used motor oil, antifreeze at maintenance area |
| Item 3.C: Controls | Oil-water separator, spill kits, covered fueling island |
| Item 4: Non-stormwater | Dye test 04/2026; wash water routed to sewer, permitted |
| Item 5: Spills | 5-gal diesel spill at fuel island, 11/2024 |
| Item 6.A: Oil and grease | Max 12 mg/l, avg 7 mg/l, grab only, lab #CA0789 |
| Item 6.F: Storm event | 0.6 in rain, 90 min, 80 hrs since last rain |
| Item 10.2: Signature | Aisha Bello, Owner, 03/01/2026 |
How to File the Completed Form
You file Form 2F with your NPDES permitting authority, not always with EPA. Send the complete package, which is Form 1 plus Form 2F plus any Form 2C, 2D, or 2E and all attachments, to the agency that issues your permit. Keep proof of filing for your records.
- Online portal. Many states require submission through NeT in EPA’s CDX system. There is usually no EPA fee, you sign electronically, processing often runs several months, and you should save the confirmation receipt and submission ID as your proof of filing.
- By mail. Where mail is allowed, send the signed package to your state agency’s permitting address or your EPA Regional Office address listed in the form instructions. Use certified mail with return receipt as your proof of filing, and keep a full copy of everything you sent.
- In person. Some state agencies accept hand delivery at their permitting office. Ask the clerk to date-stamp your copy so you hold dated proof of filing.
- State fees. EPA does not charge an application fee, but many states charge a permit application or annual fee that varies widely by state and discharge size, so confirm the amount and accepted payment method (check, ACH, or card) with your authority before you file.
Apply at least 180 days before your current permit expires, or before a new discharge begins, so the agency has time to review and your old permit does not lapse.
What Happens After You File
After you submit, the agency first checks your package for completeness. Reviewers use the same completeness checklist you used, and if the site map or sampling data is missing, they send a “notice of deficiency” asking for more before the clock really starts.
Once the application is complete, the agency drafts a permit with limits and monitoring requirements based on your data and the receiving water’s quality standards. The draft permit goes out for a public comment period, usually 30 days, during which anyone can object or ask for changes. This is why filing 180 days early matters, because the review, comment, and response steps take time.
If you applied on time, your existing permit stays in effect under “administrative continuance” until the agency acts, so you keep operating legally while you wait. Once finalized, you receive your new individual NPDES permit with its effluent limits, monitoring schedule, and reporting duties, and you must follow it from the effective date forward.
Mistakes to Avoid When Filling Out the Form
- Leaving off the site drainage map. The application is ruled incomplete and review stops before it starts.
- Omitting outdoor storage areas on the map. The reviewer cannot link pollutants to sources and sends it back.
- Reporting only impervious area in Item 3.A. The agency cannot judge runoff volume and rejects the item.
- Sampling during a non-qualifying storm. Data taken under 0.1 inch or within 72 hours of prior rain is invalid.
- Entering “ND” or “0” for low results. The rules require the actual numeric value, so the row gets rejected.
- Misplacing a decimal point in the tables. A tenfold error makes your data look implausible and triggers questions.
- Using a non-certified lab or non-approved method. Data not run under 40 CFR 136 is not accepted.
- Using data older than 3 years. Stale results do not meet the recency rule and must be redone.
- Forgetting the certified lab number column. A blank lab number can void the data row.
- Letting an unauthorized person sign Item 10.2. The certification is void and the agency will not process it.
- Filing late. Applying fewer than 180 days before expiration risks a lapse in your permit coverage.
- Forgetting the companion Form 2C, 2D, or 2E when non-stormwater is present, which leaves the package incomplete.
Do’s and Don’ts
Do: – Do download the current Revised 3-19 form, because an outdated version can be rejected. – Do label every page and attachment with your EPA ID number, so pages stay together. – Do sample during a verified qualifying storm event, so your data counts. – Do report the real numeric lab values, because the rules forbid “non-detect” entries. – Do list nonstructural controls like spill plans and training, since they count as control measures. – Do keep certified-mail receipts or portal confirmations as proof of filing.
Don’t: – Don’t guess outfall coordinates, because a wrong location maps you to the wrong water. – Don’t submit a blueprint in place of a drainage map, since it omits required flow detail. – Don’t hide a known spill, because the omission can be read as a false certification. – Don’t mix two different discharges into one outfall, since it masks pollutant sources. – Don’t let a consultant sign unless they are an authorized representative on file. – Don’t wait until your permit is about to expire, because review takes months.
Filing on Your Own vs. With Help
| Filing Pro Se (On Your Own) | Filing With an Environmental Consultant |
|---|---|
| Costs less because you pay no consultant fee | Costs more, but the fee buys sampling and mapping expertise |
| You learn your own site and controls in detail | The consultant already knows the qualifying storm rules |
| Works well for a single simple outfall | Better for many outfalls or complex toxic-pollutant tables |
| You control the timeline directly | A pro can schedule storm sampling and avoid invalid data |
| Risk of map or table errors that cause rejection | Lower risk of the common errors that delay permits |
A single-outfall scrap yard with simple runoff can often file on its own, while a multi-outfall manufacturer facing Table B and Table C toxic sampling usually saves time by hiring help to avoid a rejected application.
FAQs
Do I have to file Form 2F if I already have a general stormwater permit? No. If a general permit covers your sector and your discharge qualifies, you stay under it. You file Form 2F only when you need or are required to get an individual permit.
Do I file Form 2F by itself? No. You always file it with Form 1, and you add Form 2C, 2D, or 2E if your discharge also contains non-stormwater process wastewater.
Do I send Form 2F to EPA? No. In most states you send it to the state agency that runs the NPDES program. You send it to your EPA Regional Office only in states where EPA still administers the program.
Do I report impervious area only in Item 3.A? No. You report both the impervious surface area and the total area drained for each outfall. Reporting only one makes the item incomplete.
Do I write “ND” when a pollutant is below detection in Item 6? No. You report the actual numeric value the lab measured, even below the detection limit. The rules forbid entering “non-detect” or “0.”
Do I take only a grab sample for every pollutant in Item 6.A? No. You take a first-30-minute grab and a flow-weighted composite for most pollutants. Use grab only for oil and grease, pH, and the few listed parameters.
Do I need both latitude and longitude in Item 1? Yes. You enter degrees, minutes, and seconds for both. The agency uses them to confirm which water body receives your discharge.
Do I count a drainage ditch as an outfall? Yes. An outfall is any point source, including a ditch or channel, not just a pipe. A swale that reaches a stream must be listed.
Do nonstructural controls like a spill plan count in Item 3.C? Yes. Spill prevention plans, employee training, inspections, and housekeeping all count as control measures and should be listed.
Do I have to sample during a specific kind of storm? Yes. You sample during a qualifying storm event, meaning rain over 0.1 inch that falls at least 72 hours after the last measurable rain.
Do I have to report a small spill from two years ago in Item 5? Yes. You report any significant leak or spill of a toxic or hazardous pollutant in the last 3 years, with its date, location, and amount.
Do I have to file 180 days early? Yes. Existing dischargers must apply at least 180 days before the current permit expires so coverage does not lapse during review.
Do I need a certified laboratory for my samples? Yes. Analyses must use methods approved under 40 CFR 136 and, where required, a certified lab, and you enter the lab number in the table.
Do I need to keep proof that I filed? Yes. Keep your certified-mail receipt or your online portal confirmation and submission ID, because it proves you met the 180-day deadline.
Related reading
- How to Fill Out Florida DEP NPDES Industrial Stormwater Permit + FAQs
- How to Fill Out Michigan EGLE NPDES Industrial Stormwater Permit + FAQs
- How to Fill Out Pennsylvania DEP NPDES Industrial Stormwater Permit + FAQs
- How to Fill Out the Ohio EPA NPDES Industrial Stormwater Permit (OHR000007) + FAQs
- How to Fill Out the NPDES Individual Permit Application (Form 1) + FAQs
- How to Fill Out the NPDES Permit Application Form 2C (w/Examples) + FAQs
- How to Fill Out the Washington Ecology Water Quality Modification Permit + FAQs