Examples are the Upper and Lower peninsulas of the U.S. state of Michigan, the Scandinavian Peninsula and the Niagara peninsula.[1][2][3][4] The surrounding water is usually understood to be continuous, though not necessarily named as a single body of water.
A vacuum breaker is an attachment commonly placed on a bibcock valve or toilet or urinal flush valve, that prevents water from being siphoned backward into the public drinking water system. This prevents contamination should the public drinking water system's pressure drop. vacuum breaker typically contains a plastic disc that is pressed forward by water supply pressure, and covers small vent holes.
[See Figure 1.] Where a hose is to be attached to a serrated hose end, the vacuum breaker must be installed at least 6 above the highest point to which the hose can be raised. [See Figure 1.] Vacuum breakers must be installed in a plumb and level position, perpendicular to the finished floor.