Water quality inspection items

Please refer to the following website of the Ministry of Health, Labour and Welfare for specific reference values for each item.
http://www.mhlw.go.jp/stf/seisakunitsuite/bunya/topics/bukyoku/kenkou/suido/kijun/kijunchi.html (external site)

The Water Supply Law stipulates water quality standards for 51 items as water quality requirements to be provided by the water supply.
Tap water supplied by the water utility must conform to this standard.
Water quality standard items are divided into items related to health and items related to the properties that tap water should have.

Standards have been set so that people drink tap water for a lifetime (generally 70 years) does not affect health.

Standards are set so that when using tap water as domestic water, standards are set so that there are no obstacles such as color, turbidity, smell, etc., or that there is no obstacle to management of water supply facilities such as corrosiveness.

Although there is a certain detection in tap water, it was not set as a water quality standard because the evaluation of toxicity was provisional, or it has not been detected in tap water to date so far. As items to be noted in water quality management, such as those that may be detected at an even greater concentration than before, target values have been set from the viewpoint of ensuring the safety of tap water in the future.

It is an item that cannot be classified into water quality standard items and water quality management target setting items due to reasons such as uncertain toxicity evaluation or unknown amount in water purification.