Today’s Water Quality

Water Quality and Water Resources

： 131 water taps in the Tokyo Metropolitan Area
： Purification Plants
For inquiries in relation to the cities of Musashino, Akishima, Hamura, and the village of Hinohara, please contact the Water Supply Departments of those local government agencies.

Click on the following chart to expand it.

131 water taps in the Tokyo Metropolitan Area have installed automatic water quality meters. Every day at 9 a.m. we update the data obtained from the meters about “residual chlorine concentration”, “turbidity” and “color”.
*Because the data are preliminary figures, those figures may be corrected at a later date.
*From April 1, 2016, the automatic water quality meter at Station No. 45 has moved to Toyosu in Koto-KU

Residual chlorine concentration data for 131 water taps in the Tokyo Metropolitan area (as of 9 o’clock this morning.) The numbers of each water tap, together with their locations, are shown on the map above.
Tap No.	Residual chlorine concentration	Tap No.	Residual chlorine concentration	Tap No.	Residual chlorine concentration	Tap No.	Residual chlorine concentration	Tap No.	Residual chlorine concentration
1		31		61		91		121
2		32		62		92		122
3		33		63		93		123
4		34		64		94		124
5		35		65		95		125
6		36		66		96		126
7		37		67		97		127
8		38		68		98		128
9		39		69		99		129
10		40		70		100		130
11		41		71		101		131
12		42		72		102		（Units:：mg/L）
13		43		73		103
14		44		74		104
15		45		75		105
16		46		76		106
17		47		77		107
18		48		78		108
19		49		79		109
20		50		80		110
21		51		81		111
22		52		82		112
23		53		83		113
24		54		84		114
25		55		85		115
26		56		86		116
27		57		87		117
28		58		88		118
29		59		89		119
30		60		90		120

The results for turbidity and color are here.

Results for “turbidity” >>

Turbidity data for 131 water taps in the Tokyo Metropolitan area (as of 9 o’clock this morning.) The numbers of each water tap, together with their locations, are shown on the map above.
Tap No.	Turbidity	Tap No.	Turbidity	Tap No.	Turbidity	Tap No.	Turbidity	Tap No.	Turbidity
1		31		61		91		121
2		32		62		92		122
3		33		63		93		123
4		34		64		94		124
5		35		65		95		125
6		36		66		96		126
7		37		67		97		127
8		38		68		98		128
9		39		69		99		129
10		40		70		100		130
11		41		71		101		131
12		42		72		102		（Units:degrees)
13		43		73		103
14		44		74		104
15		45		75		105
16		46		76		106
17		47		77		107
18		48		78		108
19		49		79		109
20		50		80		110
21		51		81		111
22		52		82		112
23		53		83		113
24		54		84		114
25		55		85		115
26		56		86		116
27		57		87		117
28		58		88		118
29		59		89		119
30		60		90		120

Results for “color” >>

Color data for 131 water taps in the Tokyo Metropolitan area (as of 9 o’clock this morning.) The numbers of each water tap, together with their locations, are shown on the map above.
Tap No.	Color	Tap No.	Color	Tap No.	Color	Tap No.	Color	Tap No.	Color
1		31		61		91		121
2		32		62		92		122
3		33		63		93		123
4		34		64		94		124
5		35		65		95		125
6		36		66		96		126
7		37		67		97		127
8		38		68		98		128
9		39		69		99		129
10		40		70		100		130
11		41		71		101		131
12		42		72		102		(Units: degrees)
13		43		73		103
14		44		74		104
15		45		75		105
16		46		76		106
17		47		77		107
18		48		78		108
19		49		79		109
20		50		80		110
21		51		81		111
22		52		82		112
23		53		83		113
24		54		84		114
25		55		85		115
26		56		86		116
27		57		87		117
28		58		88		118
29		59		89		119
30		60		90		120

Explanation of Terms
Residual Chlorine	Chlorine, which is used as a disinfectant, is present in the water supply in extremely small concentrations. Under the Waterworks Law, disinfection by chlorine is mandated for the purpose of maintaining hygiene. Maintaining a concentration greater that the national minimum standard of 0.1mg/L is required by law, and Bureau of Waterworks Tokyo Metropolitan Government sets a target value to be maintained of between 0.1 mg/L and 0.4 mg/L.
Turbidity	This indicates the degree of muddiness of water. This is a matter of judgement as to whether the water from the public water supply meets the requirement of being “almost completely colorless and transparent in appearance” according to standard criteria of 2 degrees or less. Where this is achieved, this can be called clear water, free from muddiness. However the Bureau of Waterworks Tokyo Metropolitan Government sets an ever stricter standard of no more than 0.1 degrees.
Color	This shows the color of the water and this is a matter of judgement as to whether the water from the public water supply meets the criteria of being “almost completely colorless and transparent in appearance. Water whose color is no greater than the standard value (a range of 5 degrees or below) is considered colorless. However the Bureau of Waterworks　Tokyo Metropolitan Government sets an even stricter standard of no more than 1 degree.