NYC DEP Stormwater Construction Permit: A Guide for Owners and Developers

If you're planning construction in New York City, the stormwater question comes down to two numbers. Since February 15, 2022, NYC DEP's Unified Stormwater Rule has required a Stormwater Pollution Prevention Plan (SWPPP) and a DEP Stormwater Construction Permit for any project that disturbs 20,000 square feet or more of soil or creates 5,000 square feet or more of impervious surface, anywhere in the five boroughs. No work on a covered project may start until DEP issues that permit.

This guide covers whether your project counts, each step from SWPPP to permit, what happens on site, how close-out works, and who may prepare the plan and inspect. For how stormwater rules differ from building-envelope rules, see SWPPP vs. Local Law 126.

What the Unified Stormwater Rule Covers

The Unified Stormwater Rule (USWR) took effect on February 15, 2022. It updated and aligned two chapters of Title 15 of the Rules of the City of New York: Chapter 31, which sets stormwater quantity and flow-rate requirements, and Chapter 19.1, DEP's construction and post-construction stormwater permitting program. Everything below is about Chapter 19.1.

The rule made two big changes. Chapter 19.1 now applies citywide, in combined-sewer areas as well as the separate storm sewer (MS4) areas it covered before. And the threshold dropped: DEP's permit used to apply at one acre of disturbance, and only in MS4 areas. DEP says the SWPPP requirements are the same in both.

Does Your Project Count?

DEP calls a project that needs a permit a covered development project: development activity, public or private, that involves or results in any of the following.

• Soil disturbance of 20,000 square feet or more. Soil disturbance results from activities such as clearing, grading, excavation, demolition, construction, stockpiling and placing fill.
• Creation of 5,000 square feet or more of impervious surface. Areas where impervious cover was removed within five years before the SWPPP is submitted also count.
• Work that is part of a larger common plan of development or sale that will reach either number, even if the current phase doesn't on its own.

A few details catch people out:

• Off-site work counts. DEP counts all disturbance the project causes, including outside the property line.
• One-, two- and three-family homes aren't automatically exempt. They're covered when they meet the definition.
• Skipping the sewer connection isn't a way out. DEP says choosing not to connect to a City sewer doesn't relieve an applicant of the permit requirements, and there's no self-certification under Chapter 19.1.

What's excluded

• Routine maintenance and emergency work immediately necessary to protect life, property or natural resources aren't covered development projects.
• Roadway milling and paving of 20,000 square feet or more in the public right of way must follow the erosion and sediment control practices in Chapter 7 of the NYC Stormwater Manual, but doesn't need a permit.
• Projects draining to waters of the state through a NYSDEC-approved outfall don't need a DEP permit, unless the City owns or operates that outfall.
• Sites with no public combined or storm sewer available may be told by DEP, after it receives an application, that no permit is required.

If your project sits near either number, have it measured before you design around an assumption. Stockpiling, work outside the lot line or a later phase of the same plan can push a project over. If you're not sure, we can assess it.

The Permit Sequence, Step by Step

DEP's process runs in a fixed order:

1. 01Prepare the SWPPP. A qualified professional prepares, signs and seals it. Every SWPPP covers erosion and sediment control. Unless the project is one of the erosion-control-only types DEP lists (such as underground linear utilities), it must also capture and treat the water quality volume and meet the minimum runoff reduction volume in the NYC Stormwater Manual.
2. 02Submit it in SWPTS. The SWPPP and application go to DEP electronically through the Stormwater Permitting and Tracking System (SWPTS).
3. 03DEP review. DEP issues a determination within 45 days of a complete application and fee, or 60 days for non-conforming designs. If DEP finds deficiencies, it sends a notice listing them and a new application goes in.
4. 04SWPPP Acceptance. When DEP approves the plan, it provides a signed SWPPP Acceptance Form. The acceptance expires two years from issue, with one one-year extension available on written request and a fee.
5. 05NYSDEC Notice of Intent (MS4 projects). For projects in MS4 areas, the owner files a Notice of Intent under the state Construction General Permit, GP-0-25-001, and includes DEP's signed SWPPP Acceptance Form. DEP needs proof of state coverage before it issues the permit for an MS4 project.
6. 06Permit Initiation Form. The owner or developer files it with the name and contact details of the Qualified Inspector, and lists the Qualified Inspector in SWPTS.
7. 07Permit Request Form. The contractor with primary responsibility for the site certifies that it will comply with the rules, the SWPPP and the permit, and provides the trained contractor's credentials.
8. 08Stormwater Construction Permit. DEP issues the permit once its prerequisites are met. A copy must be displayed on site during construction.
9. 09Seven-day notice. DEP must be notified at least seven days before development activity starts.

If the project also needs a Site Connection Proposal under Chapter 31 (for example, for a new sewer connection), DEP's Bureau of Water and Sewer Operations reviews it separately, and its certification is also required before the Stormwater Construction Permit is issued.

Once issued, the permit must be renewed every two years. It expires if work doesn't start within one year, if work isn't finished by the date in the permit, or if work is suspended or abandoned for 12 months in a row. It doesn't replace any other city, state or federal permit, including Department of Buildings requirements, and where the city rule and the state permit differ, the stricter provision applies.

During Construction

Once work starts, the SWPPP becomes a schedule, and two roles carry it:

• The Qualified Inspector inspects on a fixed calendar, checking the erosion and sediment controls and pollution prevention measures, and whether stormwater management practices are being built as the SWPPP shows.
• A trained contractor inspects daily. Each subcontractor working on a part of the project in the SWPPP needs its own, with four hours of NYSDEC-endorsed training every three years.

How often the Qualified Inspector visits

• Standard: at least once every seven calendar days.
• Twice every seven days, at least two full calendar days apart, when more than five acres are disturbed at one time (which needs DEP's prior written approval) or the site discharges to an impaired waterbody.
• Once every 30 days during a temporary shutdown, only after DEP approves a Temporary Shutdown Request in SWPTS. DEP needs at least seven days' notice before the shutdown.

Inspections continue until DEP approves the Notice of Termination or the Stormwater Maintenance Permit. Substantial completion of the building doesn't end them.

Reports and corrective action

The Qualified Inspector prepares a report after every inspection, signed by the inspector who did it and the Qualified Inspector certifying it. It records the date, time, weather and soil conditions, total soil disturbance, the condition of each practice, and corrective actions needed, with color, date-stamped photos. Reports stay on site with the SWPPP, available to DEP on request, and a monthly summary is emailed to DEP at the address on the SWPPP Acceptance Form. DEP's rule requires inspection records to be kept for five years after construction ends.

When something needs fixing, the Qualified Inspector must notify the owner or operator and the responsible contractor within one business day of the inspection, and the contractor must begin the work within one business day. Inspectors also check that inactive disturbed areas are stabilized within 14 days, or 7 days on sites disturbing more than five acres or discharging to an impaired waterbody. If inspections have already slipped, see what happens if you miss a SWPPP inspection in NYC.

Close-Out

A project is ready to close when the SWPPP work is complete and the site has reached final stabilization: all soil disturbance has stopped, and either a uniform, perennial vegetative cover with 80 percent density covers the entire pervious surface, or equivalent stabilization measures cover every disturbed area not under permanent structures, concrete or pavement.

The Qualified Inspector performs a final inspection and certifies that the SWPPP work is done, disturbed areas are stabilized and temporary erosion and sediment controls are removed, then signs the certification statements on the Notice of Termination (NOT) in SWPTS. A Qualified Professional certifies the stormwater management practices and confirms that as-built drawings have been prepared.

The NOT goes to DEP for sign-off first. For MS4 projects, the owner then submits the signed NOT to NYSDEC, which ends state coverage with a Letter of Termination.

The Stormwater Maintenance Permit

If the SWPPP includes post-construction stormwater management practices (SMPs), the obligation continues. After final stabilization, the project needs a DEP Stormwater Maintenance Permit. The application includes the NOT, an as-built plan, an operation and maintenance manual naming who is responsible for long-term maintenance, and the fee. Once the SMPs are installed and operating as designed, DEP signs the NOT and issues the permit.

From then on, the owner submits an annual certification for the SMPs and renews the permit every five years, both through SWPTS. City capital projects need one too. Projects with erosion and sediment controls only, and underground utility lines where the surface is restored to its existing condition, don't. As-built drawings must be kept for the life of each practice.

Who Can Prepare the SWPPP and Who Can Inspect

DEP's requirements are stricter than the state's, and on a DEP-permitted project they're the ones to follow:

• SWPPP preparer: a New York licensed Professional Engineer (PE) or Registered Landscape Architect (RLA) on projects with SMPs; a Certified Professional in Erosion and Sediment Control (CPESC) on projects with erosion and sediment controls only. Any part involving the practice of engineering must be prepared by, or under the direct supervision of, a New York PE.
• Qualified Inspector: a New York PE or RLA on projects with SMPs; a CPESC on erosion-and-sediment-control-only projects. Where the Qualified Inspector is a PE or RLA, a colleague at the same company with four hours of NYSDEC-endorsed training every three years can inspect under their direct supervision.
• SMP Inspector: a New York PE or RLA, who signs and seals the SMP certification.

The state Construction General Permit accepts a wider group as Qualified Inspector, but on a NYC project with SMPs, DEP's narrower rule applies.

How VetraCheck Can Help

VetraCheck's licensed engineers handle the stormwater side of NYC construction projects in all five boroughs. We check whether a project is a covered development project, prepare and seal the SWPPP, handle the DEP permit applications in SWPTS, and serve as the Qualified Inspector from the first inspection through close-out. The team that writes the plan inspects against it, so the reports match what DEP accepted. To start, send your site plan and scope through our page on SWPPP preparation and inspections in NYC.

Sources: NYC DEP, Unified Stormwater Rule (Title 15 RCNY Chapter 19.1) and Unified Stormwater Rule FAQs; NYC Stormwater Manual; NYC DEP Stormwater Permitting Process Summary Diagram; NYC DEP Qualified Inspector Guidance; NYSDEC SPDES General Permit for Stormwater Discharges from Construction Activity, GP-0-25-001, and its fact sheet.