Who needs a SWPPP in New Hampshire?
Any construction project that disturbs one acre or more — or is part of a larger common plan of development reaching one acre — needs a SWPPP under New Hampshire permit NHR100000.
New Hampshire runs its own delegated stormwater program. Operators obtain coverage from U.S. EPA Region 1 under EPA 2022 Construction General Permit (NHR100000), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.
New Hampshire adds requirements worth flagging early: Comply with the New Hampshire-specific conditions (CWA section 401 certification) in 2022 CGP Part 9.1.1.
What the plan must contain
A New Hampshire SWPPPis the site's compliance binder — the document an inspector opens first. It documents:
- 1Site & project descriptionTotal and disturbed acreage, soils, slopes, and the sequence of construction.
- 2Receiving waters & discharge pointsWhere stormwater leaves the site and the waterbodies it reaches.
- 3Erosion & sediment control BMPsSilt fence, stabilized entrances, inlet protection, and stabilization measures.
- 4Inspection schedule & recordsDated, signed inspection logs and the corrective actions taken.
- 5Operator certificationThe SWPPP is signed by the legally responsible party before work begins.
Required and conditional BMPs
| Best management practice | Category | Status |
|---|---|---|
| Perimeter silt fence / sediment barrier | Sediment control | Required |
| Stabilized construction entrance | Tracking control | Required |
| Storm drain inlet protection | Sediment control | Required |
| Soil stabilization (seeding, mulch, blankets) | Erosion control | Required |
| Concrete washout containment | Good housekeeping | Required |
| Sediment basin or trap | Sediment control | Conditional |
| Dewatering / turbidity controls | Pollution prevention | Conditional |
Filing your Notice of Intent
Develop the SWPPP first, then prepare and submit the Notice of Intent electronically through EPA’s NPDES eReporting Tool (NeT), accessed through CDX (https://cdx.epa.gov/cdx), at least 14 calendar days before commencing construction; coverage begins 14 calendar days after EPA confirms a complete NOI unless EPA delays or denies it. Exception: construction in response to a public emergency (e.g. mud slides, earthquake, extreme flooding, widespread disruption of essential public services) whose work requires immediate authorization may discharge on the condition that a complete and accurate NOI is submitted within 30 calendar days after commencing construction activities, with documentation of the emergency in the SWPPP (Part 7.2.3i). A paper NOI (Appendix H) may be used only with a waiver from the EPA Regional Office (2022 CGP Part 1.4 and Parts 1.4.1–1.4.3, Table 1).
A Notice of Termination closes coverage once the site reaches final stabilization. Keeping the SWPPP and its inspection records on site is what keeps a project clear of stop-work orders.
Inspection requirements
The permit allows 2 inspection schedules; the operator follows one and records the choice in this plan: (a) 7-day schedule — inspect at least once every 7 calendar days (2022 CGP Part 4.2.1); or (b) 14-day schedule with storm inspections — inspect at least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.25 inch of rain or more within a 24-hour period (or within 24 hours of a snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period; smaller storms that together produce 0.25 inch in 24 hours count; for a storm producing 0.25 inch or more on consecutive days, inspect within 24 hours of the first day and within 24 hours after the last such day; when the 24 hours fall entirely outside normal working hours, inspect by the end of the next business day) (2022 CGP Part 4.2.2 (footnote 68)). Where the Part 4.3.1 increased frequency applies (portions of the site discharging to sediment- or nutrient-impaired waters, Tier 2, Tier 2.5, or Tier 3 waters, or waters within Lands of Exclusive Federal Jurisdiction), it takes the place of these schedules for the affected portion of the site (2022 CGP Part 4.3); sites discharging dewatering water also inspect the dewatering discharge once per day on which it occurs (Part 4.3.2). Every inspection is dated and signed, and any failed control is corrected before the next storm.
| Trigger | Requirement |
|---|---|
| Routine — 7-day schedule | At least once every 7 calendar days |
| Routine — 14-day schedule with storm inspections | At least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.25 inch of rain or more within a 24-hour period (or within 24 hours of a snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period; smaller storms that together produce 0.25 inch in 24 hours count; for a storm producing 0.25 inch or more on consecutive days, inspect within 24 hours of the first day and within 24 hours after the last such day; when the 24 hours fall entirely outside normal working hours, inspect by the end of the next business day) |
How New Hampshire differs from the federal permit
| New Hampshire | Federal (EPA) | |
|---|---|---|
| Authority | U.S. EPA Region 1 | U.S. EPA |
| Permit | NHR100000 | EPA CGP |
| Disturbance threshold | 1 acre | 1 acre |
| Plan name | SWPPP | SWPPP |
Because New Hampshire administers its own program, the federal EPA Construction General Permit does not apply directly here — the state permit governs. Sites inside a regulated municipal storm sewer system may carry additional local ordinance requirements on top of the state permit.
Frequently asked questions
Does New Hampshire require an engineer to prepare the SWPPP?+–
No. New Hampshire does not require a licensed PE stamp on a construction SWPPP statewide. The operator certifies the plan; engineer review is optional for complex sites.
What is the disturbance threshold in New Hampshire?+–
One acre — including sites under an acre that are part of a larger common plan of development totaling one acre or more.
How often must inspections happen in New Hampshire?+–
The permit allows 2 inspection schedules; the operator follows one and records the choice in this plan: (a) 7-day schedule — inspect at least once every 7 calendar days (2022 CGP Part 4.2.1); or (b) 14-day schedule with storm inspections — inspect at least once every 14 calendar days and within 24 hours of the occurrence of a storm producing 0.25 inch of rain or more within a 24-hour period (or within 24 hours of a snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period; smaller storms that together produce 0.25 inch in 24 hours count; for a storm producing 0.25 inch or more on consecutive days, inspect within 24 hours of the first day and within 24 hours after the last such day; when the 24 hours fall entirely outside normal working hours, inspect by the end of the next business day) (2022 CGP Part 4.2.2 (footnote 68)). Where the Part 4.3.1 increased frequency applies (portions of the site discharging to sediment- or nutrient-impaired waters, Tier 2, Tier 2.5, or Tier 3 waters, or waters within Lands of Exclusive Federal Jurisdiction), it takes the place of these schedules for the affected portion of the site (2022 CGP Part 4.3); sites discharging dewatering water also inspect the dewatering discharge once per day on which it occurs (Part 4.3.2).
New Hampshire-ready in minutes
Siltworks fills in your site data automatically, applies the New Hampshire requirements, and hands you an inspection-ready SWPPP — at 70–90% less than a consultant.
Requirements summarized from the publicly available EPA 2022 Construction General Permit (NHR100000) for planning purposes. The operator must review and certify every SWPPP before use.