WEPA Database


Last Updated : 16 November 2022.

Japan is located in the eastern monsoon region of Asia and noted for having one of highest accumulations in the world. Most of the available water is discharged to the ocean unused due to the steep topography, very short streams as well as intensive rainfall in rainy and typhoon seasons.

Legal framework

Conservation of Water Quality in Public Water

The law governing “Environmental Quality Standards for Water Pollutants”

General Measures

The law governing “Factory effluent control, notification of factory establishment, monitoring orders, continuous monitoring, measures for domestic wastewater”

The law governing “Construction of sewerage”

The law governing “Installation of Johkasou , regulation of desludging and production, registration system of johkasou installation worker, licence system of Johkasou desludging technician, etc.”

Special Measures in Enclosed Water Bodies
Lakes and Reservoirs

Special regulations for Planning of plan for the preservation of lake water quality.


Control of total pollutant load, and countermeasures against eutrophication.

Seto Inland Sea
Ariake Sea/ Yatsushiro Sea
Biwa Lake
Potable Water Sources
Groundwater Quality Conservation

Environmental quality standards for groundwater

General Measures

Regulations for toxic substances from factories, purifying orders for polluted groundwater, and continuous monitoring

Sound Water Cycle

Holistic and integrated implementation of policies on water cycle

Other Laws Related to Water Environment

Institutional Arrangement of water