The 2026 Kumamoto Earthquake, Japan

On July 28, 2026, an earthquake with a magnitude of 7.1 struck, with its epicenter in Kumamoto Prefecture.

(Kumamoto Prefecture is located in central Kyushu, one of Japan’s four large islands, in the southwestern part of the country. Strong shaking was observed across a wide area of Kyushu.)

Severe damage has occurred, particularly within Kumamoto Prefecture, including Kumamoto City, which hosted the 4th Asia-Pacific Water Summit in 2022. The disaster has had a significant impact on lives, property, and the infrastructure that supports daily life and society.

We would like to extend our heartfelt sympathies to all those affected by the disaster. We would also like to express our deepest respect and appreciation to everyone working tirelessly to provide support on the ground.

The Japan Water Forum has collected information on emergency response efforts and initiatives aimed at recovery and reconstruction in response to the water-related impacts of the 2026 Kumamoto Earthquake. We would like to share an overview of the current situation and will continue to update this information. We do so in the hope of supporting swift relief and recovery efforts and helping to reduce the impacts of natural disasters around the world.

1. Overview of the 2026 Kumamoto Earthquake and Its Impacts

2. Water-Related Damage and Ongoing Response Efforts

(1) Water Supply

(2) Wastewater Treatment and Sanitation Facilities

(3) Rivers, Dams, and Sediment Control Facilities

(4) Agricultural Reservoirs and Irrigation Canals

(5) Coastal Areas and Ports

This document has been prepared by extracting and providing a provisional English translation of water-related information from the following reference materials:

Cabinet Office, Government of Japan, Damage Situation and Response to the 2026 Kumamoto Earthquake (as of 10:00, August 17, 2026).
Ministry of Land, Infrastructure, Transport and Tourism (MLIT), Damage Situation and Response to the 2026 Kumamoto Earthquake (Report No. 44, as of 10:00, August 18, 2026).
Meeting Materials for the Joint Session of the 17th Meeting of the Government On-Site Extreme Disaster Management Headquarters and the 24th Meeting of the Kumamoto Prefectural Headquarters for Disaster Control (August 17, 2026).

1. Overview of the 2026 Kumamoto Earthquake and Its Impacts

Date and Time: July 28, 2026, at 16:27 JST
Magnitude: 7.1*
Human and Housing Damage: A total of 396 casualties, including 39 fatalities, and damage to 31,951 houses, of which 1,449 were completely destroyed (as of 14:00 on August 17).
Evacuation Status: At its peak, 9,931 people were evacuated to 506 shelters. As of 09:00 on August 17, 3,122 people remain evacuated in 72 shelters.
A tsunami advisory was issued for the Ariake Sea and Yatsushiro Sea following the earthquake, but it was lifted at 18:10 on the same day.

* The magnitude is based on current estimates and may be revised following further analysis.

2. Water-Related Damage and Ongoing Response Efforts by Stakeholders

Following the disaster, the Kumamoto Prefectural Headquarters for Disaster Control, headed by the Governor of Kumamoto Prefecture, was established immediately at 16:27 on July 28. At the national level, the Extreme Disaster Management Headquarters, headed by the Prime Minister of Japan, was established at 18:20 on the same day, followed by the establishment of an on-site disaster response headquarters on July 30. With the cooperation of relevant organizations and agencies, damage assessments and emergency response measures were carried out.

(1) Water Supply Services

The earthquake caused water outages in 15 municipalities in four prefectures, affecting a maximum of approximately 108,100 households.

The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and the Japan Water Works Association (JWWA) promptly dispatched advance teams to affected municipalities to assess damage and identify restoration needs.
To provide technical assistance to severely affected municipalities, the dispatch of water utility engineers began on August 1. In response to requests from JWWA, water utilities and contractors from across Japan have also joined recovery efforts. On August 2, the Japan Sewage Works Agency (JS)* also began dispatching personnel.

Five days after the earthquake, the number of households without water was reduced by half, to approximately 46,800 households (as of 07:30 on August 2). As of 14:00 on August 17, more than 90% of water service has been restored, although 7,380 households remain without water.

Inspection and emergency restoration work is continuing with the goal of fully restoring water service by the end of August. Water supply and sewerage operators are prioritizing the restoration of pipelines serving critical facilities such as evacuation shelters, hospitals, and welfare facilities.

* Since July 1, 2025, amendments to relevant legislation have enabled JS to provide disaster recovery support for damaged water supply facilities in addition to sewerage facilities.

Emergency Water Supply Support

JWWA, water utilities across Japan, regional bureaus of MLIT, the Japan Self-Defense Forces (JSDF), and other organizations have been providing emergency water supplies in areas affected by water outages using more than 100 water tank trucks. At ports, water supply support and bathing services have also been provided using vessels operated by MLIT regional bureaus, the Japan Coast Guard, JSDF, the Fisheries Agency, and other organizations.
The Japan Water Agency transported and installed portable water treatment units in the affected area (Hikawa Town) and has been providing drinking water and domestic water supplies. Since August 9, these units have also been used to supply water to bathing facilities.
An On-Site Emergency Water Supply Support Headquarters was established to coordinate emergency water supply operations. In cooperation with relevant organizations, it assesses water supply needs at critical facilities, including evacuation shelters, medical institutions, and welfare facilities. Emergency water supplies are provided according to identified priorities.

Provision of Well Water During Emergencies

Based on a pre-existing agreement, Kumamoto City released information on wells owned by private businesses that can provide well water to local residents.

Source: Kumamoto City

Support for Restoration of Damaged Wells

To support residents whose wells were damaged by the earthquake and who are not connected to public water systems, a Well Water Response Team was established within the On-Site Emergency Water Supply Support Headquarters on August 11.
The team is assessing damage and restoration needs while considering measures such as dispatching specialist contractors to support well restoration.

Emergency Water Services Using Water Recycling Systems

The WOTA BOX*, a portable water-recycling shower system developed by WOTA Corporation, has been deployed primarily at evacuation shelters. As of August 13, 2026, a cumulative total of 123 units had been deployed through cooperation among public and private sector stakeholders, including the provision of equipment by local governments nationwide.
WOTA Corporation is also seeking support to expand the installation and operation of WOTA BOX units and WOSH handwashing stands* at medical and welfare facilities.

* WOTA BOX and WOSH are both portable and capable of recycling up to 98% of wastewater.

Source: WOTA Fact Sheet on the 2026 Kumamoto Earthquake Response (Second Preliminary Report). Figures are preliminary as of August 13, 2026.

(2) Wastewater Treatment and Sanitation Facilities

Sewerage

Inspections of sewerage facilities were conducted in the affected areas.
MLIT, local governments across Japan*, JS and the Japan Sewer Collection System Management Association dispatched sewerage engineers to the affected areas to conduct inspections and emergency restoration work.
Emergency restoration surveys were conducted on approximately 282 km of sewer pipelines. All work, including emergency restoration work at eight locations requiring such measures, was completed on August 13. Investigations for permanent restoration are ongoing.

* Under the nationwide mutual assistance framework of the Japan Sewage Works Association, sewerage engineers from local governments across Japan were dispatched to the affected areas.

Agricultural Community Wastewater Treatment Facilities

Inspections have been completed in all 119 districts subject to inspection.
Abnormalities were identified in wastewater treatment facilities in three districts in Kumamoto Prefecture, and emergency restoration work is being undertaken.

Sanitation Facilities

To improve sanitation conditions, MLIT dispatched 15 containerized toilets pre-positioned at roadside stations (Michi-no-Eki) to the affected areas by August 6, and is preparing to dispatch an additional eight units.
In cooperation with the national government, Kumamoto Prefecture installed a total of 296 additional toilet units at evacuation shelters, including 26 mobile toilet vehicles* and 120 temporary toilets.

* Mobile toilet vehicles are vehicles equipped with onboard toilet facilities.

(3) Rivers, Dams, and Sediment Control Facilities

Nationally Managed Rivers

Inspections have been completed for all 29 rivers subject to inspection in six river systems.
Damage, including cracks on levee crests, was identified at 91 locations across eight rivers in three river systems.
Along the Kuma River, subsidence, cracking, and deformation were observed over approximately 250 meters of levee, prompting emergency restoration work at three locations. These works have already been completed.
Emergency measures have also been completed at the remaining 88 damaged sites.
In the lower reaches of the Kuma River, the flood danger water level threshold used for issuing flood forecasts, which serve as a basis for evacuation decisions during floods, has been temporarily lowered to account for the increased flood risk following the earthquake.

Prefecturally Managed Rivers

Inspections have been completed for all 218 rivers subject to inspection in 72 river systems.
In Kumamoto Prefecture, levee subsidence and damage to revetments were identified at 295 locations along 43 rivers under prefectural management. Emergency measures have been completed at all identified sites.
For seven prefecturally managed rivers, the flood danger water level thresholds used for issuing water level information, which serve as a basis for evacuation decisions during floods, have been temporarily lowered to account for the increased flood risk following the earthquake.

Dams

Inspections have been completed for all 57 dams subject to inspection, and no abnormalities were identified.

Sediment Disaster Prevention

Inspections have been completed for all sediment control facilities subject to inspection.
Damage to facilities such as rockfall protection fences was identified at two locations in Kumamoto Prefecture, and response measures are being considered.
In municipalities that recorded a seismic intensity of Upper 5 or higher on the Japanese scale, provisional criteria were introduced for issuing Level 4 Sediment Disaster Alerts, which serve as a basis for evacuation orders by local authorities. These criteria allow alerts to be issued at lower rainfall thresholds, 70% to 80% of the standard criteria, reflecting the increased risk of sediment-related disasters following the earthquake.

(4) Agricultural Reservoirs and Irrigation Canals

The Rural Development Bureau of the Ministry of Agriculture, Forestry and Fisheries (MAFF) dispatched agricultural engineering personnel to provide technical guidance and support damage assessments.

Disaster Prevention Priority Irrigation Reservoirs*

Inspections have been completed for all 674 Disaster Prevention Priority Irrigation Reservoirs subject to inspection.
Abnormalities were identified at 56 reservoirs.
At sites where cracks were identified in reservoir embankments, emergency measures have been implemented, including covering the embankments with plastic sheeting to prevent rainwater infiltration that could lead to embankment failure.

* A designated agricultural reservoir whose failure could cause flooding and serious damage to surrounding communities.

Agricultural Dams

Inspections have been completed for all 75 agricultural dams subject to inspection.
An abnormality was identified at one dam, where leakage was found at a joint in the discharge pipe.

Main Irrigation Canals

In Yatsushiro City, a section of the Shiranui Main Irrigation Canal collapsed.
In Hikawa Town, subsidence was observed in a main irrigation canal.
The national government and Kumamoto Prefecture carried out emergency restoration work at the respective sites.
To secure irrigation water needed for agricultural activities such as tomato transplanting and strawberry seedling cultivation, MAFF deployed temporary pumping equipment and implemented other emergency measures from July 30 onward.

(5) Coastal Areas and Ports

Coastal Facilities

Inspections have been completed along all 110 coastal sections subject to inspection.
Cracks and other damage to seawalls were identified along 10 coastal areas within Kumamoto Prefecture, but emergency countermeasures have already been completed.

Ports

At Yatsushiro Port in Kumamoto Prefecture, all public quay walls were damaged, including ground displacement behind the quay walls, liquefaction, and localized depression.
Following emergency restoration work and on-site assessments, nine berths were available for use as of 14:00 on August 17. These berths have been utilized for the maritime transport of relief supplies and the provision of emergency water supply support.

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