33 CFR 245.55: Permit requirements.

(a) Permits for removal. Marking and removal operations by the owner, operator or lessee are normally permitted under nationwide permits for such activities as outlined in part 330 of this chapter. The activities must meet certain conditions as stated in those regulations, and additional permits may still be required from state or local agencies.

(b) Special conditions. The Corps of Engineers may add individual or regional conditions to the nationwide permit, or require an individual permit on a case-by-case basis.