There are regions of Eastern Asia that are very arid, and others that are very tropical.  Overall, water supplies in the area are abundant.

Some of the largest rivers in the world are in Eastern Asia.  These include the Ganges (Ganga), Brahmaputra, Chang Jiang (Yangtze Kiang), and Yenisei.  There are also many lakes, including Dongting-hu in China, Tonle Sap in Cambodia, and Kasumigaura in Japan.

Though East Asia has significant water supplies, it often has difficulty tapping its resources.  Storage facilities are often unavailable, water sometimes flows where it is inaccessible, and water often does not come at all, or comes in great floods.

Water resources vary throughout Eastern Asia.  In Singapore, only 200 cubic meters are available per person, while Papua New Guinea has about 186,000 cubic meters per capita.  Some areas suffer from a generally arid climate, while others suffer from an overly dense population.

The region is faced with problems associated with severely damaged water supplies. Pollution from sewage, industrial chemicals, agriculture, and mining all ruin the water, and pathogenic pollution affects all but the wealthiest East Asian nations.  Pathogens are now appearing in lakes and rivers, and are having a dangerous effect on health.

Fresh water is also increasingly becoming a victim of salinization, making the water less useful.  Seawater enters into fresh water supplies, and ground water is also withdrawn to the oceans.

One major cause of the loss of fresh water reserves is agriculture.  However, the general problem of population growth is also a major factor.