Water needs were provided by cisterns, which gathered rain waters, due to lack of natural spring in the area of Alanya Castle. As seen today, each traditional house has had its own cistern. Besides, large cisterns in the area ensured a general water supply. Castle (İçkale) is also called Cistern Castle for holding large cisterns in it. Most of the cisterns are 13th century structures.
Mecdüddin Cistern located in Hisariçi Neighborhood is a 13th century building. Rectangular plan with barrel vaulted, the structure is bordered with quarry stone walls, raised from exterior. Grog with brick wall at interior, its surface is plastered. A small section with raised wall on west side gives U shape to plan of the cistern. On upper part, there are total three shafts for water extraction and one drain hole.