The Washington Construction Stormwater General Permit (CSWGP) is the state permit that every construction operator must get before clearing, grading, or excavating one acre or more of ground that could send polluted runoff toward Washington’s lakes, rivers, wetlands, or groundwater. You apply for it by filing an electronic Notice of Intent (eNOI), Ecology Form ECY 020-85, through Ecology’s online WQ Web Portal.
This permit exists because dirty construction runoff is one of the largest sources of sediment pollution in the state, and a single rainstorm on bare soil can dump tons of mud into a salmon stream. The current version took effect January 1, 2026, and it carries a tough new rule that surprises many builders: every site, no matter how small, must now use a Certified Erosion and Sediment Control Lead (CESCL) for inspections. Roughly 60 days of lead time stand between your application and the day you can legally turn dirt, so the order in which you act matters as much as the form itself.
Here is what you will learn in this guide:
- 📋 Exactly who must file the CSWGP and who can skip it with an erosivity waiver
- 🗂️ Every document and number to gather before you open the eNOI
- ✍️ A line-by-line walkthrough of each Notice of Intent field, with sample entries
- 🧭 Three full filing examples for the most common Washington project types
- ⚠️ The costly mistakes that delay coverage and how to dodge each one
What the CSWGP Is and Who Must File It
The Construction Stormwater General Permit is a combined federal and state water-pollution permit. On the federal side, it carries out the National Pollutant Discharge Elimination System (NPDES) program under the Clean Water Act. On the state side, it is a State Waste Discharge permit under Washington’s Water Pollution Control Act, RCW 90.48. The Washington Department of Ecology issues it and enforces it.
You must apply for coverage if your project meets any one of three triggers. First, your site disturbs one acre or more of land. Second, your site disturbs less than one acre but is part of a larger common plan of development, such as a phased subdivision or a binding site plan. Third, your site has the potential to discharge construction stormwater or process water to a surface water or storm drain that reaches state waters.
“Disturbed acreage” includes off-site areas you tear up as a direct result of the project, such as equipment staging yards, borrow pits, and material stockpiles, unless those areas already carry their own permit. Many operators undercount their acreage by ignoring these off-site areas, which leads to the wrong fee tier and a coverage challenge later.
The permit forces operators to do three core things: write and follow a Stormwater Pollution Prevention Plan (SWPPP), install erosion and sediment controls called Best Management Practices (BMPs), and obtain and keep coverage until the site is stable. Failing to get coverage when you need it is a Clean Water Act violation that can draw penalties of tens of thousands of dollars per day, so the threshold question is not one to guess on.
Before You Start: Documents and Information You Need
Treat the eNOI like a tax return: gather everything first, then fill it once. The form asks for facts that live in your civil plans, your deed, your SEPA file, and your local GIS maps, so hunting for them mid-application is where most filers stall. Below is the pre-filing checklist. Each item matters, and each one carries a consequence if it is missing.
- Legal operator name and UBI number. Ecology cross-checks this against state business records, and a mismatch stalls your account setup.
- Site street address and legal description. Without a precise location, Ecology cannot tie your discharge to the right receiving water, and your application is incomplete.
- Total disturbed acreage, including off-site areas. This number sets your annual fee and your sampling duties; undercount it and you risk an enforcement correction.
- Latitude and longitude of the site. The portal maps your project, and a wrong coordinate can route your file to the wrong regional office.
- Names of receiving waters. You must name every lake, stream, wetland, or storm sewer that takes your runoff, or Ecology cannot run its water-quality review.
- SEPA threshold determination. You need your SEPA decision or exemption on hand, because the eNOI asks for it directly.
- A site map with all 11 required elements. The map must upload with the eNOI, and a missing element bounces the application back.
- Newspaper for public notice. You must line up a paper that circulates in your county before you publish two legal notices.
- SAW, Ecology Signature, and WQ Web Portal accounts. These three logins are mandatory to submit, and creating them can take a day or two you must build into your 60-day window.
- Contaminated soil or groundwater records. The 2026 permit expands what counts as contamination, so dig up any environmental site assessments first.
If any single item is missing when you start, the portal lets you save a draft, but an incomplete eNOI does not start your 60-day clock, and that delay is the number-one reason projects miss their dirt-turning date.
Where to Get the Form and How to Access It
The Notice of Intent is filed electronically, not on paper, for nearly all applicants. You reach it through Ecology’s WQ Web Portal, which is the front door to the State of Washington Water Quality Permitting and Reporting System (PARIS). Everything you enter becomes public information in PARIS, so accuracy is not optional.
Before you can open the eNOI, you must set up three linked accounts in this order. First, create a Secure Access Washington (SAW) account, which is the state’s single sign-on. Second, add an Ecology Signature account, which lets you legally sign the form online. Third, request access to the WQ Web Portal and add the Construction Stormwater service. Each step can take part of a business day to verify, so start a week ahead.
The official paper form, Notice of Intent (NOI) Form ECY 020-85, still exists for the rare applicant who cannot use the portal, such as someone without reliable internet who requests a waiver from Ecology. The paper route is slower and is discouraged. Whichever route you use, confirm you are working with the form tied to the 2026 permit, because using an outdated NOI tied to the expired 2021 permit creates conflicts that Ecology must reject and reprocess.
Step-by-Step: How to Fill Out the Notice of Intent (Form ECY 020-85) Line by Line
The eNOI is organized into logical groups: operator information, site information, discharge and receiving-water information, SEPA and public notice, the site map upload, and the certification signature. Work through them in order. Below, each major field gets its own walkthrough.
Field 1: Operator (Permittee) Legal Name and Contact
This field asks who is legally responsible for the permit. Enter the full legal name of the operator exactly as it appears in state business records, not a nickname or “doing business as” tag unless that is the registered name. For a company, add the Unified Business Identifier (UBI) number, mailing address, phone, and email.
For example, Cedar Ridge Builders LLC enters its legal name, UBI 604 123 456, and the email of its responsible officer. The operator is usually the party with day-to-day control of construction, which is often the general contractor, not the landowner.
A common edge case is a project with two operators, such as a developer who controls the master plan and a contractor who controls the dirt work. In that case, each operator who has control must obtain its own coverage or be named, because shared control without shared coverage leaves a gap.
The most common mistake here is naming the property owner when the contractor actually runs the site. The consequence is that Ecology holds the wrong party responsible, and enforcement letters go to someone who cannot fix the problem. A frequent misconception is that “operator” always means the owner; in truth, it means whoever has operational control of the construction activities.
Field 2: Site Name and Physical Location
This field asks where the work happens. Enter the project or site name and the physical street address, including city, county, and ZIP. If there is no street address yet, give the nearest intersection, crossroads, or a clear descriptive location.
For example, Marcus Bell, running a 10-acre subdivision, enters site name Willow Crossing Phase 1, location NE corner of SR 9 and 84th St NE, Snohomish County. He also enters the latitude and longitude, 48.0312, -122.1045, which he pulled from the county GIS map.
The nuance arises for linear projects like a pipeline or road, where there is no single address. For these, you describe the start and end points and the route between them. The most common mistake is entering the office address of the company instead of the dirt-work address, which sends inspectors to the wrong place and delays review. The misconception is that the mailing address and site address are interchangeable; they are not, and Ecology treats the physical site location as the controlling fact.
Field 3: Total Acreage and Disturbed Acreage
This field asks how big the project is and how much soil you will expose. Enter the total project acreage and, separately, the total acreage that will be disturbed, including off-site staging, stockpile, and borrow areas tied to the job. Round to the nearest tenth of an acre.
For example, Cedar Ridge Builders enters total site 0.9 acres but disturbed acreage 1.3 acres, because a half-acre off-site staging yard pushes the disturbance over one acre. That higher number is what triggers coverage and sets the fee.
The edge case is phased construction. Even if you only open part of the site at a time, the total planned disturbance over the life of the common plan is what counts, and a phased plan that totals more than five acres can never use an erosivity waiver. The most common mistake is reporting only the building footprint and ignoring the graded and staged areas around it, which understates acreage and creates a fee dispute. The misconception is that “disturbed” means only where the building sits; it actually means all cleared, graded, excavated, or stockpiled ground.
Field 4: Latitude and Longitude
This field asks for the precise map coordinates of your site. Enter latitude and longitude in decimal degrees, using a negative sign for the longitude since Washington is west of the prime meridian. Pull the values from your jurisdiction’s GIS site or a mapping tool.
For example, Janet Cho, building a single home on a small lot, enters 47.6588, -117.4260 for her Spokane-area parcel. The portal then drops a pin she must confirm sits on her actual site.
The edge case is a large or linear site where one point cannot capture the whole project; here you give the approximate center or the primary discharge point. The common mistake is dropping the sign on longitude or swapping the two numbers, which lands your pin in another state and confuses Ecology’s mapping. The misconception is that coordinates are optional if you gave a street address; they are required and serve as the legal map reference.
Field 5: Receiving Waters (Discharge and Outfall Locations)
This field asks where your stormwater goes when it leaves the site. You must identify all discharge locations, the points at the site boundary where water exits, and all outfall locations, the points where that water reaches a surface water or soaks into the ground. Name every receiving water by its proper name, and list groundwater if you infiltrate.
For example, Marcus Bell lists two discharge points along his north property line and names the outfall as unnamed tributary to Quilceda Creek. He found the creek name by reviewing the county’s drainage GIS maps and walking the site.
The tricky edge case is that an outfall can sit far from your site, downstream of a long municipal storm pipe, so a desk review alone often misses it. The common mistake is naming only the nearest ditch and missing the named stream it feeds, which makes Ecology’s water-quality review incomplete and stalls coverage. The misconception is that discharge and outfall mean the same thing; the discharge is at your fence line, and the outfall is where the water finally lands.
Field 6: SEPA Compliance
This field asks about your State Environmental Policy Act review. Enter your SEPA threshold determination, such as a Determination of Nonsignificance, the lead agency, and the file or project number. If your project is SEPA-exempt, state the exemption.
For example, Willow Crossing Phase 1 enters Determination of Nonsignificance (DNS) issued by Snohomish County, file PFN 2025-0418. Janet’s single-home build, by contrast, enters the categorical SEPA exemption for single-family residences.
The edge case is a project still in SEPA review when the 60-day window is closing; you should not file the eNOI until the SEPA decision is final, because the SEPA process feeds the water-quality analysis. The common mistake is leaving this blank or guessing the determination, which voids the application’s environmental basis. The misconception is that SEPA and the stormwater permit are the same review; they are separate, and one does not replace the other.
Field 7: Public Notice Information
This field asks you to document the two legal newspaper notices that the permit requires. Enter the name of the newspaper, the two publication dates, and attach proof of publication. The notices must run once a week for two weeks in a row, with seven days between them, in a paper that circulates in your project’s county.
For example, Cedar Ridge Builders publishes in the Snohomish County Tribune on June 4, 2026 and June 11, 2026, then enters both dates. The standard notice text names the operator, the project, the acreage, the activities, and the receiving waters, and invites public comment.
The critical timing nuance is that a 30-day public comment period begins on the date of your second publication, and Ecology will not issue coverage until that period ends. The common mistake is publishing in a paper that does not serve the project county, which makes the notice invalid and forces a costly republish. The misconception is that one notice is enough; the law requires two, properly spaced, or the clock never starts.
Field 8: Site Map Upload (11 Required Elements)
This field asks you to attach a map of your project. Upload a single clear site map that shows all 11 required elements, the same map that anchors your SWPPP. The map must show direction of north, property lines, existing structures and roads, cut and fill slopes with top and bottom catch lines, slopes and contours with stormwater flow before and after grading, disturbed and undisturbed areas, BMP locations, off-site storage and borrow areas, all surface waters including wetlands, every off-site discharge point, sampling station locations, finally stabilized areas, and proposed entrances.
For example, Marcus Bell uploads a one-page engineered map that labels each element with a legend, so a reviewer can check off all 11 at a glance. He marks his silt fence, his stabilized construction entrance, and his sampling station near the north discharge point.
The edge case is a large site that needs more than one sheet; you may submit a multi-sheet map as long as every element appears and the sheets are clearly linked. The common mistake is omitting the direction of stormwater flow or the sampling stations, which are the two elements reviewers flag most, and a missing element bounces the eNOI. The misconception is that a plain plat map will do; the site map must be drainage-focused and show the 11 listed items, not just lot lines.
Field 9: Contaminated Soil and Groundwater Disclosure
This field asks whether your site has known contamination. State whether soil or groundwater contamination is present, the type, and any cleanup status. The 2026 permit widened the definition of contamination, so report any prior spills, fill of unknown origin, or sites with an environmental assessment flagging concerns.
For example, Aisha Rahman, redeveloping a former gas-station lot, discloses petroleum-contaminated soil, under a cleanup action with Ecology’s Toxics Cleanup Program. That disclosure changes her sampling and handling duties.
The edge case is an old industrial parcel with unknown history; if you are unsure, an environmental site assessment before filing protects you. The common mistake is answering “no” to save time when records suggest otherwise, which is a false certification and can void the permit. The misconception is that this question only applies to obvious Superfund sites; the broadened 2026 language reaches many ordinary infill and redevelopment lots.
Field 10: Certification and Electronic Signature
This final field asks you to swear the application is true. Read the certification statement, then sign electronically with your Ecology Signature account. The signer must be a responsible corporate officer, a general partner, a proprietor, or a duly authorized representative such as a site superintendent.
For example, Cedar Ridge Builders’ managing member, David Ng, signs as the responsible officer, because he can bind the company. He confirms his Signature account credentials to complete the submission.
The edge case is delegation; if a superintendent signs, the operator must have an authorization on file naming that person. The common mistake is having an unauthorized employee sign, which makes the certification invalid and the permit voidable. The misconception is that an electronic signature is less binding than ink; under Washington law it carries the same legal weight and the same penalties for a false statement.
Three Filled-Out Examples Using Real Scenarios
Below are three of the most common Washington filing situations, each followed from start to finish through the key eNOI fields.
Scenario 1: Janet’s Single-Lot Home With an Erosivity Waiver
Janet is building one house on a 0.8-acre lot near Spokane and wants to avoid full permit coverage by qualifying for an erosivity waiver.
| eNOI Section | What Janet Enters |
|---|---|
| Operator legal name | Janet Cho, sole proprietor |
| Site name and location | Cho Residence, 4127 N Cedar Rd, Spokane County |
| Total disturbed acreage | 0.8 acres |
| Latitude / longitude | 47.6588, -117.4260 |
| Receiving waters | Infiltration on site, no off-site discharge |
| SEPA status | Categorically exempt, single-family residence |
| Construction season | July 1 – September 30 (dry season) |
| Waiver basis | R factor below 5, under 5 acres, dry-season work |
Because her erosivity waiver shows an R factor under 5, a site under 5 acres, and all work in the dry season, Janet files the waiver instead of seeking full coverage.
Scenario 2: Marcus’s 10-Acre Subdivision Needing Full Coverage
Marcus is the general contractor on a 10-acre residential subdivision that discharges to a creek, so he needs standard CSWGP coverage.
| eNOI Section | What Marcus Enters |
|---|---|
| Operator legal name | Bell Site Development LLC, UBI 603 998 221 |
| Site name and location | Willow Crossing Phase 1, SR 9 & 84th St NE, Snohomish County |
| Total disturbed acreage | 10.4 acres including staging |
| Latitude / longitude | 48.0312, -122.1045 |
| Receiving waters | Unnamed tributary to Quilceda Creek |
| SEPA status | DNS, Snohomish County, PFN 2025-0418 |
| Public notice dates | June 4, 2026 and June 11, 2026 |
| Site map | Engineered map with all 11 elements |
Marcus files his eNOI at least 60 days before grading, publishes both notices, and waits out the 30-day comment period before coverage issues.
Scenario 3: Aisha’s Phased Common Plan of Development
Aisha manages a phased commercial redevelopment on a former gas-station lot that totals 7 acres across three phases.
| eNOI Section | What Aisha Enters |
|---|---|
| Operator legal name | Rahman Commercial Group Inc. |
| Site name and location | Eastgate Commons, 1500 Main St, Yakima County |
| Total disturbed acreage | 7.0 acres, phased common plan |
| Latitude / longitude | 46.6021, -120.5059 |
| Receiving waters | Municipal storm sewer to Yakima River |
| SEPA status | DNS, City of Yakima |
| Contamination disclosure | Petroleum-contaminated soil, TCP cleanup |
| Waiver eligibility | Not eligible, total plan exceeds 5 acres |
Because the full common plan tops 5 acres, Aisha cannot use a waiver even though each phase is small, so she files for full coverage and discloses the contamination.
How to File the Completed Notice of Intent
Washington offers two filing channels, and the electronic route is the standard for almost everyone.
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Online (required for most): WQ Web Portal. Submit the eNOI through Ecology’s WQ Web Portal using your SAW and Ecology Signature accounts. There is no application fee. Processing runs about 60 days from a complete application, including the 30-day public comment period, and your proof of filing is the confirmation and PARIS record in the portal, which you should screenshot and save.
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Paper (waiver only): mail to Ecology. If Ecology grants you a hardship waiver from electronic filing, mail the signed Form ECY 020-85 to the Water Quality Program, Construction Stormwater, Washington State Department of Ecology, P.O. Box 47696, Olympia, WA 98504-7696. There is still no application fee, processing is slower, and your proof of filing is the certified-mail receipt you should keep.
After coverage issues, the annual permit fee kicks in. Fees are set by rule under WAC 173-224, billed by the state fiscal year, and scaled to acreage, running from roughly $800 for the smallest sites to several thousand dollars for the largest. Ecology bills you after coverage is granted and every year until you terminate, and construction stormwater holders cannot use the bi-annual billing or small-business fee reductions that some other permits allow.
What Happens After You File
Once your complete eNOI posts to PARIS, Ecology runs a public and technical review. The 30-day public comment period that started on your second newspaper publication must finish first, and during that window any person may write Ecology with concerns about your discharge.
Ecology reviews comments and checks whether your discharge could cause a measurable change in receiving-water quality. If it could, Ecology applies the Tier II antidegradation test under WAC 173-201A-320, asking whether the project is necessary and in the overriding public interest. Most routine sites clear this review without trouble.
When the comment period closes and the review passes, Ecology issues your coverage letter and permit number, and only then may you legally discharge construction stormwater. From that day forward you must follow your SWPPP, run weekly and post-storm inspections through a CESCL, sample as your site size requires, and file monthly Discharge Monitoring Reports. Skipping these steps after coverage is just as serious as building without a permit.
Mistakes to Avoid When Filling Out the Form
- Filing fewer than 60 days before discharge. Coverage will not be ready in time, and you cannot legally turn dirt.
- Undercounting disturbed acreage. You land in the wrong fee tier and face an enforcement correction.
- Ignoring off-site staging and borrow areas. Your acreage is understated and your coverage can be challenged.
- Naming the owner instead of the true operator. Ecology holds the wrong party, and enforcement misses the real decision-maker.
- Using the office address as the site address. Inspectors go to the wrong location and review stalls.
- Dropping the sign or swapping latitude and longitude. Your map pin lands far away and confuses Ecology’s review.
- Listing only the nearest ditch as the receiving water. The named downstream stream is missed and the water-quality review is incomplete.
- Publishing public notice in the wrong newspaper. The notice is invalid and you must republish, restarting the clock.
- Submitting a site map missing one of the 11 elements. The eNOI bounces back and you lose days.
- Answering “no” to contamination without checking records. That false certification can void the permit and trigger penalties.
- Letting an unauthorized employee sign. The certification is invalid and the permit is voidable.
- Forgetting to budget for SAW and Signature account setup. Account delays eat into your 60-day window.
Do’s and Don’ts
Do:
- Do start your SAW, Signature, and WQ Web Portal accounts a week before you plan to file, because account setup takes time.
- Do walk the site to confirm discharge and outfall points, since maps alone often miss a distant outfall.
- Do count all disturbed ground, including off-site areas, so your fee tier and sampling duties are correct.
- Do confirm your newspaper circulates in the project county, or the legal notice will not count.
- Do save the PARIS confirmation as proof of filing, because it is your evidence the clock started.
- Do hire or designate a CESCL early, since the 2026 permit requires one for every site.
Don’t:
- Don’t guess your SEPA determination, because a wrong entry voids the environmental basis of the application.
- Don’t file before your SEPA decision is final, since the review depends on it.
- Don’t assume an erosivity waiver covers a phased plan over 5 acres, because it never can.
- Don’t reuse an old 2021-permit NOI form, as Ecology must reject it.
- Don’t skip the second public notice, since the comment clock needs both notices.
- Don’t begin grading before your coverage letter arrives, because that is an illegal discharge.
Pros and Cons of Filing on Your Own vs. With Help
| Filing Pro Se (On Your Own) | Filing With a Consultant or CESCL |
|---|---|
| Saves consultant fees, helpful on a tight budget | Costs money, but often less than one penalty |
| Builds your own knowledge for future projects | Brings expertise on tricky outfall and acreage calls |
| Full control over timing and submission | Faster turnaround since pros know the portal |
| No need to schedule outside help | Cleaner site maps that pass the 11-element check |
| Fine for simple single-operator sites | Strong fit for phased, contaminated, or large sites |
For Janet’s simple single-lot waiver, filing pro se makes sense. For Aisha’s phased, contaminated commercial site, professional help usually pays for itself by avoiding rejections and penalties.
FAQs
Do I need this permit if my site is under one acre?
Yes. You still need it if your site is part of a larger common plan of development or has the potential to discharge construction stormwater to state waters.
Can I skip the permit with an erosivity waiver?
Yes. You can if your site is under 5 acres, has an R factor below 5, and finishes all work within the dry-season window for your region.
Is there a fee to apply?
No. There is no application fee, but an acreage-based annual permit fee begins once Ecology grants coverage and continues yearly until termination.
Do I file online or on paper?
Yes. You file the electronic Notice of Intent through Ecology’s WQ Web Portal; paper is allowed only if Ecology grants you a hardship waiver.
Do I enter my company office address or the construction site address in the location field?
No. Do not use the office address; the location field needs the physical construction site address or nearest descriptive location.
Do I list only the nearest ditch as my receiving water?
No. You must name every receiving water in the path, including the downstream stream, lake, or wetland the ditch eventually feeds.
Does “disturbed acreage” include off-site staging areas?
Yes. It includes off-site staging, stockpile, and borrow areas tied to your project unless those areas carry their own separate permit coverage.
Do I need a CESCL even on a small site?
Yes. The 2026 permit requires a Certified Erosion and Sediment Control Lead for inspections on every site, regardless of size.
Can the property owner sign the certification instead of the contractor?
Yes. The signer can be the owner only if the owner is a responsible officer or duly authorized representative; otherwise the true operator must sign.
Do I publish public notice only once?
No. You must publish twice, once a week for two consecutive weeks with seven days between them, in a paper that circulates in your county.
Can I start grading as soon as I submit the eNOI?
No. You must wait until Ecology issues your coverage letter after the 30-day public comment period and technical review are complete.
How long does coverage take to issue?
Yes. Plan on about 60 days from a complete application, which includes the mandatory 30-day public comment period before coverage is granted.
Do I report contaminated soil even on an ordinary infill lot?
Yes. The 2026 permit broadened the contamination definition, so disclose any known soil or groundwater contamination, prior spills, or unknown fill.
How do I end my permit and stop the fees?
Yes. You file a Notice of Termination after soils are stabilized and BMPs removed; fees continue until Ecology grants termination, which takes about 30 days.
Related reading
- How to Fill Out the Washington Forest Practices Application/Notification (FPA/N) + FAQs
- How to Fill Out the Washington Ecology NPDES Industrial Stormwater Permit (NOI) + FAQs
- How to Fill Out the Washington Ecology Water Quality Modification Permit + FAQs
- How to Fill Out the Washington Ecology NPDES Construction Stormwater Permit (Notice of Intent) + FAQs
- How to Fill Out Washington Ecology NPDES Industrial Stormwater Permit (2025 ISGP) + FAQs
- How to Fill Out the Washington Ecology Water Quality Modification Permit (Form ECY 070-361) + FAQs