33 CFR 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

Regulations last checked for updates: Feb 09, 2026

Title 33 - Navigation and Navigable Waters last revised: Feb 03, 2026

View all text of Subpart B [§ 2.20 - § 2.38]

§ 2.34 - Waters subject to tidal influence; waters subject to the ebb and flow of the tide; mean high water.

(a) Waters subject to tidal influence and waters subject to the ebb and flow of the tide are waters below mean high water. These terms do not include waters above mean high water caused by flood flows, storms, high winds, seismic waves, or other non-lunar phenomena.

(b) Mean high water is the average of the height of the diurnal high water at a particular location measured over a lunar cycle of 19 years.

authority: 14 U.S.C. 503; 33 U.S.C. 70031; Public Law 89-670, 80 Stat. 931, 49 U.S.C. 108; Public Law 107-296, 116 Stat. 2135, 2249, 6 U.S.C. 101 note and 468; Department of Homeland Security Delegation No. 0170.1

source: USCG-2001-9044, 68 FR 42598, July 18, 2003, unless otherwise noted.

cite as: 33 CFR 2.34