水冷是一种液体冷却方式，一般是指用水等水性液体来冷却机器。其冷却运行方式跟油冷大同小异，都是将水在机器的水道里和在外部用喉管连接的散热器不停地穿流冷却。

水冷是当今汽车用引擎的主流冷却方式。另外有些电脑，特别是超频的，也使用水冷来带走CPU及GPU等组件所发出的热量。

Water cooling is a method of heat removal from components and industrial equipment. As opposed to air cooling, water is used as the heat conductor. Water cooling is commonly used for cooling automobile internal combustion engines and large industrial facilities such as steam electric power plants, hydroelectric generators, petroleum refineries and chemical plants. Other uses include cooling the barrels of machine guns, cooling of lubricant oil in pumps; for cooling purposes in heat exchangers; cooling products from tanks or columns, and recently, cooling of various major components inside high-end personal computers. The main mechanism for water cooling is convective heat transfer.