54 states and territories

A nationwide permit authorises a discharge under section 404 of the Clean Water Act, but section 401 of the same Act separately requires the state or territory where the discharge happens to certify that it will not violate state water quality standards. A state can grant that certification outright, grant it subject to its own conditions, waive it, or deny it.

Any of those outcomes changes what a nationwide permit actually authorises on the ground. A condition attached to a state certification becomes a condition on the nationwide permit itself in that state, and a denial can block a nationwide permit from authorising the activity at all, even though the federal Corps rule would otherwise allow it.