OSAKA -- Following months of fierce heat and below-average rainfall, authorities ordered a reduction in water taken from Lake Biwa and the Yodo River from Saturday, affecting Shiga, Kyoto, Osaka and Hyogo prefectures.

Water levels in Lake Biwa fell to 95 cm below average on Saturday. The measure, introduced at 10 a.m., was the first time a reduction has been ordered in the amount taken from both the lake and river since the summer of 1994, when severe water shortages were recorded across much of Japan.

The restrictions apply to water for household, industrial and agricultural use, with a 10 percent reduction in effect on the lower reaches of the Yodo River in Osaka and Hyogo Prefectures.

A 5 percent reduction has been imposed on Shiga Prefecture, which relies on Lake Biwa for its water supplies.

Water supply to residents will not be cut off completely, officials said.

The restrictions apply to water purification plants, the Hanshin Water Supply Authority, which supplies tap water to Kobe, private sector factories that use the Lake Biwa and Yodo River water supply and plants that drain irrigation water in the area.

Construction Ministry officials at the Kinki regional bureau will inspect purification plants to check that the restrictions are being met.

Prefectural government authorities also plan to set up a water shortage headquarters in each prefecture to call for cooperation with the efforts to reduce water use.