Japan Data

Only 40% of Japan’s Water Supply Systems Earthquake Resistant


Japan faces regular earthquakes, but a recent government report found that the national average seismic compliance rate of main water pipelines is just 42.3%.

A report released by the Ministry of Health, Labor, and Welfare showed that, as of the end of fiscal 2022, the earthquake resistance of water supply systems across Japan continued to remain low at around 40%.

The national average seismic compliance rate of main pipelines, such as conduits and water supply pipes, increased year-on-year by 1.1 percentage points to 42.3%. By prefecture, Kanagawa rated top with 73.6%, followed by Tokyo with 66.8%, and Saitama 62.3%. The prefecture with the worst seismic compliance rate was Kōchi at 24.8% and there was a tendency overall for the rate to be higher in the east of Japan and lower in the west.

Top and Bottom 10 Prefectures for Seismic Compliance Rate of Main Pipelines

Meanwhile, the earthquake resistance rate for water purification plants rose from the previous year by 4.2 percentage points to 43.4%. As the treatment systems take water from rivers and other sources, then purify it through a number of processes, the plants need to be completely shut down in order to make them earthquake resistant at all these stages, so in many cases it is difficult to carry out improvements. By prefecture, at 73.6%, Ishikawa came top and Kanagawa second with 73.3%. The worst was Tokyo at 13.2%, with zero progress made from the previous year.

Top and Bottom 10 Prefectures for Earthquake Resistance Rate of Water Purification Plants

The government has developed a Fundamental Plan for National Resilience in preparation for the predicted occurrence of a major natural disaster, such as an earthquake along the Nankai Trough or one that strikes directly under Tokyo. In the case of water supply, it has set a target of ensuring that the seismic compliance rate for main pipelines exceeds 60% by the end of fiscal 2028.

(Translated from Japanese. Banner photo © Pixta.)

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