33 C.F.R. § 151.2035

(a) To discharge ballast water into waters of the United States, the master, owner, operator, agent, or person in charge of a vessel subject to § 151.2025 of this subpart must either ensure that the ballast water meets the ballast water discharge standard as defined in § 151.2030(a), use an AMS as described in § 151.2025(a)(3) or ballast exclusively with water from a U.S. public water system, as described in § 151.2025(a)(2), according to the schedule in paragraph (b) of this section.

(b) Implementation Schedule for the Ballast Water Management Discharge Standard for vessels using a Coast Guard approved BWMS to manage ballast water discharged to waters of the U.S. After the dates listed in Table 151.2035(b), vessels may use a USCG-approved BWMS and comply with the discharge standard, use PWS per § 151.2025(a)(2), or use a previously installed AMS per § 151.2025(a)(3).