2026 Water Cycle White Paper | Chapter 22026 Water Cycle White Paper: Groundwater Conservation and Use

Groundwater is used for household, industrial, and agricultural purposes, as well as snow removal and energy. Springs sustained by groundwater also serve as places for biodiversity conservation, relaxation, and environmental education. In recent years, use by businesses has become more varied, driven by expanded mineral water production, clusters of advanced and next-generation semiconductor manufacturing plants and related companies, and use during disasters.

There are also efforts to combine groundwater and spring conservation and restoration with local culture and products, using them to promote tourism and brand regional specialties. In response to this diversification of demand, comprehensive management and use focused on the appropriate conservation and use of groundwater, or groundwater management, has become important. Regional challenges extend beyond technical matters such as estimating groundwater reserves and available supplies and improving water quality to include operating councils, drafting ordinances, and guiding users.

The Groundwater Management Promotion Platform provides one-stop support to local governments seeking to take action, with cooperation from relevant ministries and agencies, public institutions including advanced local governments, universities, research institutes, businesses, and NPOs. Its portal provides basic information, overviews of representative groundwater basins, ordinance enactment status, and leading practices; its consultation desk introduces the knowledge of relevant parties. The platform also makes referrals and dispatches through the Water Cycle Adviser System, and holds Groundwater Management Study Group meetings to share basic knowledge and leading practices and exchange views. It builds and operates a groundwater database for the shared use of groundwater level, water quality, extraction volume, and monitoring station data collected by national and local governments, and incorporates knowledge gained through these activities into improved guidelines and related materials.

Because much about groundwater reserves and behavior remains unclear, the government supports monitoring and surveys, data development, preservation, and analysis tailored to regional conditions. In FY2025, it held 3 study group meetings to exchange views on challenges shared by local governments and on disaster use in light of the 2024 Noto Peninsula Earthquake. It also prepared a pamphlet outlining groundwater management for local governments beginning this work. To reduce risks from major disasters and drought, the BRIDGE program advanced methods for analyzing groundwater flow in model regions and developing a simplified model that does not require detailed physical properties of the ground, based on the three-dimensional water cycle model developed under SIP.

As of October 2025, groundwater councils and similar bodies had been established by 34 prefectures and 329 municipalities, for a total of 363 bodies (20%). By type, they included 49 groundwater councils, 83 advisory and similar bodies of local governments, 102 basin water cycle councils, 103 groundwater use countermeasure councils, and 26 land subsidence-related bodies, among others. The government collected information on establishment status, types, and management activities by these councils and similar bodies, then published it on the platform website as a reference for considering their establishment.

To support local government measures such as extraction restrictions, the government surveyed prefectures and municipalities on the enactment status of ordinances and similar rules, as well as extraction cases involving foreign nationals and others. As of October 2025, 26 prefectures and 236 municipalities had a total of 269 ordinances regulating extraction; 12 local governments had identified 49 cases of extraction by foreign nationals and others. The results were compiled and published as “Survey Results on Ordinances Regulating Groundwater Extraction and Cases of Groundwater Extraction by Foreign Nationals and Others.” Groundwater information and leading practices from relevant ministries and agencies were made available in one place on a website, and opportunities were also provided to receive advice through referrals and dispatches of water cycle advisers as needed.

(4) To promote groundwater use during disasters as an alternative water source, the government took into account that groundwater and other sources were used for household water in some affected areas immediately after the 2024 Noto Peninsula Earthquake. The “Guidelines for Groundwater Use During Disasters: Using Disaster Wells and Springs,” first issued in March 2025, were revised in December 2025 to include guidance on developing new wells. The revised guidelines were published on the platform, and briefing sessions were held for local governments. In regions with limited groundwater data, efforts to secure alternative water sources through disaster wells and similar facilities were launched, and a pamphlet promoting such use to strengthen regional disaster preparedness was also prepared.

The revised guidelines are a procedural manual for local governments considering disaster well initiatives. Covered water sources include existing wells owned by individuals or businesses, springs, and new public wells. Intended uses are household water needs such as laundry, bathing, cleaning, and toilets. The guidelines address identifying and registering existing wells and springs; considering and developing new public wells; registration requirements and procedures; and points to consider for management and use in normal times and during disasters. To identify candidate areas for new wells, local governments assess household water demand during disasters and the volume of alternative water sources already secured, then compare areas by phase and location. One example procedure selects areas with insufficient secured water, excluding those where an early restoration of the water supply is expected.

To provide basic information for advancing disaster well initiatives in municipalities across Japan and to understand checklist items and implementation status under the guidelines, a survey of disaster wells was conducted from December 2025 to January 2026.