Q&A on COVID-19 (about tap water quality)

Coronavirus is generally known to detoxify (loss of infectiousness) by disinfection with chlorine or the like.
Tap water is required to be chlorinated by the Water Supply Law and to be supplied to customers' faucets while maintaining an appropriate chlorine concentration.
In City of Yokohama, Water Works Bureau, tap water has been measured 24 hours a day, 365 days a year at 43 faucets to confirm that tap water maintains an appropriateCOVID-19 concentration.
One of the basics of measures against infectious diseases such as COVID-19 and influenza is frequent hand washing. When returning home from home, before and after cooking, before meals, etc., please use familiar tap water to "frequent hand washing".
Please refer to COVID-19 infection for preventive measures.

Coronavirus is generally known to detoxify (loss of infectiousness) by disinfection with chlorine or the like.
Tap water supplied by City of Yokohama, Water Works Bureau maintains an appropriate chlorine concentration in accordance with the Water Supply Law, so tap water does not infect COVID-19.
However, when wiping with tap water, chlorine in tap water is consumed by contact with cloth, goods and air, and it is considered difficult to maintain sufficient chlorine concentration for COVID-19 eradication.
Chlorine bleach is effective as a measure against COVID-19 when wiping. It is effective to dilut the chlorine bleach for kitchen with tap water (about 0.05% as sodium hypochlorite concentration).
[Reference]
Ministry of Health, Labour and Welfare, Ministry of Economy, Trade and Industry, Consumer Affairs Agency special page "How to disinfect and disinfect COVID-19" (outside site)

In the "Response to the COVID-19 infection" (business communication dated February 17, 2020), the government expressed the view that measures in accordance with the "COVID-19 infection Guidelines for Measures against Pandemic Influenza Virus in Water Supply Operators (revised version)" are effective as measures taken by water utilities.
Under these guidelines, it is important to continue the current chlorination of water treatment plants and monitoring of residual chlorine concentrations even during the epidemic season. City of Yokohama, Water Works Bureau continues its current efforts.
Going forward, we will continue to respond appropriately based on national notices.
[Reference]
Ministry of Health, Labour and Welfare “Response to COVID-19 infection” (business communication dated February 17, 2020) (PDF: 59KB)
Ministry of Land, Infrastructure, Transport and Tourism "Promotion of new influenza measures in water supply companies" (outside site)
※In April 2024, the water supply business was transferred from the Ministry of Health, Labour and Welfare to the Ministry of Land, Infrastructure, Transport and Tourism and the Ministry of the Environment.