NWP 31: Maintenance of Existing Flood Control Facilities

Discharges of dredged or fill material resulting from activities associated with the maintenance of existing flood control facilities, including debris basins, retention/detention basins, levees, and channels that: (i) were previously authorized by the Corps by individual permit, general permit, or 33 CFR 330.3, or did not require a permit at the time they were constructed, or (ii) were constructed by the Corps and transferred to a non-Federal sponsor for operation and maintenance.

Acreage limit

The 2026 rule states no acreage limit for NWP 31. Eligibility turns on the activity description in the rule text and the general conditions that apply, not on a numeric cap.

Pre-construction notification: Always required

Every use of NWP 31 requires a pre-construction notification to the district engineer before work begins. There is no minimum-impact threshold that exempts a project from this requirement.

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 31, 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.