About 40 years later, the name was changed to the more approachable “Sewerage Day.” This decision was driven by several factors: the commemoration of the centennial of the Sewerage Act (enacted in 1900 as the original Sewerage Act), which laid the foundation for modern sewerage systems in Japan; the fact that 2001 marked the start of the 21st century; and a growing public awareness regarding the importance of sewerage systems in recent years.

September 10 was designated as the “Sewerage Day” because the date known as “Nihyaku-hatsuka” (the 220th day of the lunar calendar)—long considered the peak of typhoon season—was deemed appropriate in light of one of the sewerage system’s major roles: the drainage of rainwater.
“Nihyaku-hatsuka” (literally “the 220th day”) is one of the “Zassetsu” (Japan-specific seasonal markers signaling changes in the season); it refers to the 220th day counting from “Risshun” (the start of spring), which falls around February 4.

Every year, around the time of the “Sewerage Day,” various events related to sewerage systems are held at wastewater treatment plants across the country, with the aim of fostering public understanding and cooperation regarding these systems.

The Japan sanitation Consortium (JSC) is proud to announce that, on 3 September 2026, the consortium has signed a Memorandum of Understanding (MOU) with the Asian Development Bank (ADB) to foster collaboration and develop capacity development programs.

Established in 2009, JSC is a water knowledge hub for sanitation in the Asia and the Pacific region, aiming to support countries in the region that face low access to sanitation and wastewater-related challenges, and help developing sustainable sanitation services through information sharing and knowledge dissemination.

In several occasions in the past, JSC has collaborated with ADB in projects in India, Vietnam and China and for the publication titled: “Sanitation and Sustainable Development in Japan”. This MOU is not only an opportunity to strengthen collaboration, but also to use Japanese experience with mainstreaming wastewater treatment and ensuring management service quality, including planning methods and strategies, for optimal wastewater treatment coverage. JSC and ADB plan to jointly develop and implement country-focused capacity development programs for ADB staff and government officials from ADB member countries focusing on enhancing expertise in wastewater and sanitation technologies and management.

The agenda items deliberated at the meeting are published on the JSC website and can be accessed at the following link:

Fiscal year goals and Activities

Date and Time
Wednesday, June 10, 2026, 10:30–12:00

Venue
Fureai Furusato Hall, 2nd Floor Tokyo Niigata Kenjinkai Building
1-13-6 Ueno, Taito-ku, Tokyo 110-0005

The following agenda items are scheduled for deliberation at this meeting:

1. Minutes of the previous meeting
2. Report on activities implemented in FY2025
3. Proposed business plan for FY2026
4. Other matters

Water Environment Partnership in Asia

Asian Development Bank

Water Environment Partnership in Asia

MLIT & MOE, Japan

MOE, Japan

Water Environment Partnership in Asia