Water Day

What Is Water Day?

Every August 1st is "Water Day" (水の日, Mizu no Hi) in Japan. It was established by a Cabinet agreement on May 31, 1977, to raise public awareness of water as a finite and precious resource and of the importance of water resource development. The following week (August 1–7) is observed as "Water Week" (水の週間). August was chosen because it is a month when water use is especially high and interest in water peaks. In 2014, the Basic Act on the Water Cycle also designated August 1 as Water Day in law. Events and educational programs on water are held across Japan, led by the Ministry of Land, Infrastructure, Transport and Tourism.

Japan and Water: A Complex Relationship

Japan appears water-rich — it receives substantial rainfall, has thousands of rivers and lakes, and is surrounded by ocean. Yet Japan faces significant water challenges. Its mountainous terrain and short, steep rivers mean that rainfall runs off quickly to the sea. Uneven rainfall distribution — concentrated in the rainy season and typhoon season — means drought can threaten water supplies in dry periods.

Water Infrastructure

Japan has invested heavily in water infrastructure: dams for flood control and water storage, water treatment plants, and extensive pipe networks delivering clean drinking water throughout the country. Japanese tap water is treated and monitored under strict quality standards, and it is generally safe to drink straight from the tap. Large city systems such as Tokyo's are also known for their low leakage rates.

Water Conservation in Japan

Water-efficient appliances — particularly in bathrooms and toilets — have helped reduce household water use over time. Industrial water recycling, efficient agricultural irrigation, and the renewal of aging pipe networks are ongoing priorities.

Fun Facts

• Very little usable fresh water: About 70% of Earth's surface is covered by water, but about 97% of it is seawater. Fresh water in rivers and lakes that people can readily use is said to be only around 0.01% of all water on Earth.
• Virtual water: Producing 1 kg of beef is estimated to require about 20,000 liters of water. Through its food imports, Japan is said to indirectly use large amounts of water from other countries.
• Why ice floats: Water is densest at about 4°C and expands when it freezes, so lakes freeze from the top down and aquatic life can survive the winter below.
• Onsen (hot springs): Japan's volcanic geology gives it an abundance of hot spring sources — around 27,000 — that feed a bathing culture with roots stretching back centuries.