Water supply and sanitation in Gibraltar have been major concerns for its inhabitants throughout its history, from medieval times to the present day. The
climate of Gibraltar is a mild
Mediterranean one with warm dry summers and cool wet winters. Since daily records of rainfall began in 1790, annual rainfall has averaged a mean of with the highest volumes in December and the lowest in July. However, most of Gibraltar's small land area is occupied by the
Rock of Gibraltar, a
limestone outcrop that is riddled with
caves and crevices. There are
no rivers, streams, or large bodies of water on the peninsula, which is connected to Spain via a narrow sandy
isthmus.