DO I NEED A CONSTRUCTION STORMWATER PERMIT OR SWPPP? QUICK CHECK (FREE INTERACTIVE TOOL)
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summary     Free checker: enter acres disturbed, location, common plan status and your role to see whether a construction project likely needs NPDES stormwater permit coverage and a SWPPP, and who issues the permit.

sections
- The rules behind the check

faq
Q: Do I need a stormwater permit for less than one acre?
A: Usually not, unless the work is part of a larger common plan of development or sale that will disturb one acre or more in total, or your state or local government sets a lower threshold. Many cities require local erosion control permits for smaller sites.
Q: When is a SWPPP required for construction?
A: A SWPPP is required when a project needs construction stormwater permit coverage, generally when it disturbs one acre or more or is part of a larger common plan that does. Under the EPA CGP, it must be prepared before the Notice of Intent is submitted.
Q: Who needs to file the NOI, the owner or the contractor?
A: Under the EPA CGP, every operator needs coverage: the party with control over plans and specifications, typically the owner or developer, and the party with day-to-day operational control, typically the general contractor. Often both file.

note        Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.

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Free Interactive Tool

Do I Need a Construction Stormwater Permit or SWPPP? Quick Check

Answer four questions about your project to see whether it likely needs construction stormwater permit coverage and a SWPPP, who issues the permit, and what to do next.

  • Runs in your browser
  • Nothing is saved
On this page
  1. Calculator
  2. The rules behind the check
  3. FAQ

Construction stormwater permit coverage, and with it a SWPPP, hinges mostly on how much land you disturb and whether the work is part of a larger common plan. This screening tool applies the federal thresholds and tells you who the permitting authority probably is.

The rules behind the check

  • 1 acre or more of disturbance needs coverage under EPA's rules and most state permits.
  • Less than 1 acre needs coverage if the work is part of a larger common plan of development or sale that will disturb 1 acre or more in total, such as a lot in a subdivision.
  • Operators need coverage: the party that controls plans and specifications (often the owner or developer) and the party with day-to-day control of compliance (often the general contractor).
  • Low erosivity waiver: sites of 1 to less than 5 acres with a rainfall erosivity factor under 5 for the construction period may be waived.
  • Permitting authority: most states issue their own permits; EPA does in Massachusetts, New Hampshire, New Mexico, DC, most territories and most Indian country.

Local governments often require their own erosion and sediment control permits for smaller sites, so check with your city or county too. Learn the details in the free permit coverage lesson.

Sources and official references

Last reviewed: October 25, 2026 · Free general education based on the Clean Water Act, EPA NPDES rules and the EPA Construction General Permit. Your governing permit (EPA, state, tribal or local) controls. This is not legal advice, not EPA-approved, and not a California QSP/QSD or other state credential, and it does not issue a certificate. Nothing you enter on this page is saved or sent.

FAQ

Frequently asked questions

Usually not, unless the work is part of a larger common plan of development or sale that will disturb one acre or more in total, or your state or local government sets a lower threshold. Many cities require local erosion control permits for smaller sites.

A SWPPP is required when a project needs construction stormwater permit coverage, generally when it disturbs one acre or more or is part of a larger common plan that does. Under the EPA CGP, it must be prepared before the Notice of Intent is submitted.

Under the EPA CGP, every operator needs coverage: the party with control over plans and specifications, typically the owner or developer, and the party with day-to-day operational control, typically the general contractor. Often both file.

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