As we announced on 20 June, the water basins on the south and west side of the Forest of Tranquility have been out of use since 30 May. They were cleaned and disinfected on 7 June and tested for Legionella bacteria using the culture method. The results of this test confirmed that Legionella bacteria levels were below the detection limit.
(For reference: Cleaning and disinfection status of the Forest of Tranquillity Water Basins
https://www.expo2025.or.jp/en/news/news-20250620-05/ )
The Association has cooperated with the Osaka City Public Health Centre to review the routine maintenance and water quality testing methods for the Forest of Tranquility water basins.
As a result, based on advice from the Osaka City Public Health Centre and with reference to the hygiene standards for swimming pools, the Association has decided to control the water quality of the water basins using the following methods:
1. Monitoring residual chlorine levels during opening hours and maintaining appropriate levels.
2. Carrying out regular cleaning and water quality testing.
After a trial of residual chlorine concentration control, it has been confirmed that it is possible to maintain an appropriate chlorine concentration in the water basin on the west side, so this water basin will reopen from 11 July.
The use of the water basin on the south side will continue to be suspended as we continue to conduct trials to manage chlorine concentrations.
(Facility Maintenance and Management Bureau)