NWP 21: Surface Coal Mining Activities

Discharges of dredged or fill material into waters of the United States associated with surface coal mining and reclamation operations, provided the following criteria are met: (a) The activities are already authorized, or are currently being processed by states with approved programs under Title V of the Surface Mining Control and Reclamation Act of 1977 or by the Department of the Interior, Office of Surface Mining Reclamation and Enforcement; (b) The discharge must not cause the loss of greater than 1/2- acre of non-tidal waters of the United States.

Acreage limit

The limit NWP 21 applies depends on the water it is applied in.

Non-tidal waters: 1/2 acre of permanent loss
Tidal waters: No limit compiled for this permit

1/2-acre limit applies to non-tidal waters; valley fills are not authorised.

Pre-construction notification: Always required

Every use of NWP 21 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 21, 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.