It is the top of this page

Tap water of Yokohama?

Last update date March 22, 2019

Q
Is tap water safe?
A

We give various tests, and tap water is safe.
As for the tap water, standard of water is set to achieve "supply of clean water" in the water supply method.
Standard of water,
(1) "Item in conjunction with health" (guarantee safety for a person's health)
(2) "Item in conjunction with property that water supply should have" (we do not cause obstacle in use of life) is set.
Even if person of an average of 50kg in weight continued drinking 2 liters of water a day as for the setting of the standard value throughout the life, it was set of health as standard that influence did not occur.
In addition, standard item (51 items) is set all about thing which might produce trouble in protection of a person's health or life if we see nationwide even if it is material (item) having low rate of detection.
We establish point inspecting tap water regularly to confirm safety of tap water in Water Works Bureau and examine water.
Most of inspection items are a one-tenth or less of quality of the water standard values, and, as for the result of examination of water, toxic substances such as cyan in particular, mercury, cadmium are not detected for the past ten years. Please use in peace.

Q
Is mineral water not safe what?
A

Tap water is different from mineral water in safe guarantee level. As tap water is checked strictly in more inspection items, it may be said that it is security more.
Mineral water is determined as production standard and ingredient standard in country by "standard standards such as food, additive" of the food hygiene law.
We set this production standard about natural water to use about Japanese mineral water, and, in Haramizu to use, it is said to standard of 18 items including tap water or the public bacteria or coliform bacterium that it must be adapted water.
In addition, ingredient standard stipulated about product, and standard of eight items containing lead or arsenic is set.
Safety of mineral water is secured by these standards.
Imported foreign mineral water secures safety in ingredient standard.
In addition, in foreign mineral water, there is thing that it is said, "the results that are made with severe water source maintenance and management for 100 years or more many years, and were sold secure safety".
It may be said that tap water is security more to be different from tap water by standard of water (51 items) not to produce influence in a person's health even if we continue drinking throughout the life in safe guarantee level in mineral water by production standard (18 items) and ingredient standard (eight items) of the food hygiene law.
In addition, "oh, true children The Water" which sell in City of Yokohama, Water Works Bureau of the food hygiene law, in addition to production standard and ingredient standard, inspect 59 items including standard of water of tap water originally.

It is ... in City of Yokohama, Water Works Bureau

Standard of water item (51 items)
Once a day inspection item (three items)
Water quality management goal setting item (26 items)
We inspect examination of water item (47 items) which Yokohama-shi performs originally other than item set in country and make sure of the water supply quality of the water.
"Oh, true children The Water" inspects 59 items.
"Oh, of true children The Water" page

Q
Why is it that we inspect tap water?
A

Even how delicious water must be safe. Therefore standard of water of 51 items is set of tap water from the viewpoint of safety to health and life use top.
We perform examination of water to have confirmation (we meet standard of water) of safety of tap water and devise examination of water plan and work.
By examination of water plan, we assume doorway, water source of water purification plant inspection point in addition to water of faucet.
In addition, we carry out inspection of about 127 items that we included water quality management goal setting item saying that you should note in water quality management including material which may be detected in material and water supply detected during the public environment and Yokohama-shi's original item in for further safe security in addition to standard of water item for inspection item even if it is standard of water and unnecessary item doing.
We carry out quality control thoroughly by to carry out examination of water in City of Yokohama, Water Works Bureau in this way about many points to domestic faucet, many items, can drink water which customer is safe, and is delicious.
Page of "examination of water plan of Yokohama-shi"

In addition, examination of water goes around the quality of the water examination room of City of Yokohama, Water Works Bureau.
As you renew the quality of the water examination room in 2007 and installed visit course, you can see state of examination of water clearly.
Please apply for visit to Water Works Bureau customer Service Center.
Water Works Bureau customer Service Center
Telephone: 045-847-6262
※You run, and please be careful not to make any mistake. (prefix is "hachiyonnana".)
Fax: 045-848-4281

Q
Is chlorine bad for the health?
A

About influence on human body of chlorine used for disinfection, we do not have to worry at level of tap water.
Even if tap water continues drinking throughout the life, it is confirmed that health does not have influence.
Risk of healthy influence such as water system infections with bacteria or virus is much bigger and cannot find safety when we do not perform chlorination.
By the way, history of chlorination in Japan originated in Tokyo City (existing Tokyo) and Osaka-shi of 1921 (Taisho 10).
Japanese tap water is set now by the water supply method established in 1957 (Showa 32) to maintain residual chlorine levels with faucet 0.1 mg/L or more.
In addition, on the other hand, water quality management target value to hold down the upper limit 1 mg/L below is shown from the viewpoint of taste and smell.
Residual chlorine concentration of tap water of Yokohama was 0.5 mg/L (2014 average).

Inquiry about water supply to Water Works Bureau customer Service Center

Water Works Bureau customer Service Center

Telephone: 045-847-6262 fax: 045-848-4281
※You run, and please be careful not to make any mistake

Inquiry to this page

Water Works Bureau General Affairs Department General Affairs Division

Telephone: 045-671-3105

Telephone: 045-671-3105

Fax: 045-212-1155

E-Mail address [email protected]

Return to the previous page

Page ID: 529-771-075

We come back to the top