From what I can see online Water Cay is listed as electing one person to the Freetown Town Committee while McCleans Town is included in the High Rock Committee. The geography of this would be a little odd if that reference to Water Cay was meant to refer to Deep Water Cay instead. 

This site also mentions a historic population on a "Water Cay" without it being preceded by Deep. 

https://www.grandbahamamuseum.org/exhibits/history-of-grand-bahama-and-freeport/wilderness-tamed-beginning