Legal Definitions - low-water mark

The low-water mark is a legal boundary that refers to the lowest point reached by a body of water, such as an ocean, river, or lake, under normal or average conditions. This mark is frequently used to define the extent of private property ownership adjacent to water, distinguishing it from public lands or waters, or to establish the boundary between different jurisdictions.

• Example 1: Property Boundary on a Tidal River

  A homeowner owns a parcel of land situated along a tidal river. Their property deed specifies that the boundary extends to the "low-water mark." This means that the homeowner's private property ends at the lowest point the river water typically recedes to during an average low tide. Any land exposed beyond this point during exceptionally low tides, or the water itself, may be considered public property or subject to public access rights, rather than belonging to the homeowner.

• Example 2: Land Ownership Along a Non-Tidal Lake

  A state law dictates that private property lines for lots bordering a large, non-tidal freshwater lake extend to the "ordinary low-water mark." This legal provision ensures that during typical seasonal fluctuations or periods of moderate drought, the property owner's land extends to the usual lowest edge of the lake. It prevents property owners from automatically claiming newly exposed land during unusually severe droughts, as that land would remain part of the public lakebed.

• Example 3: Public Access Rights on a Coastal Beach

  In a coastal state, public access to beaches is legally protected, with the public's right to walk along the shore defined as extending up to the "mean low-water mark." This means that regardless of who owns the land above this line, the public has a guaranteed right to use the portion of the beach that is typically submerged at high tide but exposed at the average lowest tide. This ensures a consistent strip of beach remains accessible to the public.