NWP 18: Minor Discharges

Minor discharges of dredged or fill material into all waters of the United States, provided the activity meets all of the following criteria: (a) The quantity of discharged dredged or fill material and the volume of area excavated do not exceed 25 cubic yards below the plane of the ordinary high water mark or the high tide line; (b) The discharge of dredged or fill material will not cause the loss of more than 1/10-acre of waters of the United States; and (c) The discharge of dredged or fill material is not placed for the purpose of a stream diversion.

Acreage limit

Permanent loss of waters of the United States authorised under NWP 18 cannot exceed 0.1 acres per single and complete project.

Overall limits: 25 cubic yards and loss of no more than 1/10-acre; discharge may not be placed for the purpose of a stream diversion.

Pre-construction notification: Conditional

PCN required if: (1) the discharge or volume excavated exceeds 10 cubic yards below the ordinary high water mark or high tide line; or (2) the discharge is in a special aquatic site, including wetlands.

If a PCN is required, general condition 32 gives the district engineer 30 calendar days to determine whether it is complete, then up to 45 calendar days from receipt of the complete PCN to respond before the permittee may proceed. Those are two separate clocks, not one.

Source

Federal Register citation: 91 FR 768
Effective date: March 15, 2026
Cited text: 91 FR 768 - Reissuance and Modification of Nationwide Permits (final rule, 8 Jan 2026) Read the rule

What this page does not tell you

District regional conditions. Any of the 38 USACE districts can narrow NWP 18, add a notification requirement beyond general condition 32, or revoke the permit entirely inside its boundaries. PermitBird holds no compiled regional conditions yet. Check the district.
State Clean Water Act Section 401 certification. Each of the 54 states and territories must certify, condition, waive or deny use of this permit before it authorises a discharge there. PermitBird holds no compiled certification yet. Check the state.