Overview of Drinking Water Quality Management in Japan
日本の水道の歴史について

Yasuo Yanagibashi, MHLW, Japan
厚生労働省‑ 61 ‑

柳橋泰生

Overview of Drinking Water Quality Management in Japan

Yasuo YANAGIBASHI
Director, Office of Drinking Water Quality Management
Ministry of Health, Labour and Welfare

1. The beginning of water supply systems in JapanThe first water supply system in Japan was built in the Warring State Period in the16th century. Each of the warring lords built a big town around the castle in the area heoccupied, where securing a supply of drinking water and domestic water was a vital challengefor them. In 1545, the Hayakawa Water Supply System was built in Odawara, which was themain city in the Kanto Area at that time. In 1590, when Hideyoshi Toyotomi, who later in thesame year gained full control of the nation, transferred Ieyasu Tokugawa to Edo (now Tokyo),the construction of the Koishikawa Water Supply System was started (this system was laterrebuilt as the Kanda Water Supply System). Ieyasu Tokugawa assumed control of the nation
after the Battle of Sekigahara in 1600 and established a shogunate government in the city ofEdo. Edo then started its history of development as the nation’s political capital. In 1654, theTamagawa Water Supply System (43 km (27miles) in length and with a 92 m (302feet)difference in elevation) was completed in Edo. This system is considered to be the originalform of the current water supply systems in Tokyo and is still partially in use in the currentsystem. It is estimated that the Tamagawa Water Supply System supplied water to 1.2 million
people in Edo, which with a population of approximately 2 million, was the largest city in theworld at that time in 1787. In the same period, about 40 other cities and towns constructed asimilar water supply system.
In 1854, the Japanese government signed the Japan-U.S. Treaty of Amity and Japan
opened its doors to other countries for the first time since the beginning of the 200-year long
period of isolation. As international exchange became more active, waterborne infectious
diseases, such as cholera and typhoid, started to invade Japan from other countries and spreadthrough the nation. In the first 20 years of the Meiji Era (1868–1912), more than 410,000
Japanese were infected by cholera bacteria, and more than half of those infected lost theirlives. The outbreak served as an alarm signal for the government officials who in turn
recognized the need for a modern water supply system. The momentum to build water supplysystems was especially high in towns near a harbor, where the threat of a cholera attack washigher.
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2. Spread of the modern water supply systems
In 1883, the government of Kanagawa Prefecture invited a British engineer, Henry
Spencer Palmer, to carry out a survey and to design a pressurized water supply system that
could continuously supply filtered water in Yokohama through iron pipes. The construction
was finished in 1887, and the system, which carried water from the Sagami River, startedservices. Following Yokohama, water supply systems were constructed and services werestarted in Hakodate, Nagasaki, Osaka, Tokyo, Hiroshima, and Kobe.
By 1930, as many as 700 water supply systems were completed in Japan. After agovernment funded subsidy system for small water supply service was started in 1952,
construction of water systems proceeded at an accelerated rate. By 1960, as many as 14,984
systems were built, supplying water to 53% of the nation’s population. The number ofsystems reached 19,364 in 1970, but decreased to 14,580 by 2000 due to the integration ofsmall systems into a single comprehensive system that covers a wider area. More recently, theofficial definition of private water supply systems was changed in 2002 to cover a wider rangeof systems, and as a result, the total number of systems on record in the same year (17,599systems covering 97% of the nation’s population) became higher than the previous year.

3. The current legal system regarding water supply systems in JapanThe high rate of spread of the current water supply systems in Japan is largely due
to the Water Works Law, which was established in 1957 aimed at the well-planned
construction of water supply systems and the protection and improvement of existingwaterworks. Currently, the following types of systems are supplying water to consumers inJapan under the regulations listed below.
It should be noted that the Water Works Law specifies a “water supply system” as awhole facility that is used to supply water suitable for human consumption (i.e., drinkingwater) through pipes and other types of structures. Facilities that are temporary constructions
are exempted from the scope of the law.
(1) Types of water supply systems
a. Water supply service:
A service that supplies drinking water through a water supply system to a
population of 101 or larger, responding to a demand from the public.
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b. Small water supply service:
A service that supplies drinking water through a water supply system that supplies
water to 5,000 consumers or fewer. Although not defined by the Law, water supply service
that supply water to more than 5,000 people are customarily referred to as “jo-suido jigyo”(literally “upper water supply services”).
c. Wholesale water supply service:
A service that provides water to water suppliers.
d. Private water supply system:
A water supply system for private use at a school or company dormitory, sanatorium,or other type of public housing whose the number of consumers exceeds 100 or whose
maximum daily capacity of water supplied exceeds 20 cubic meters (706 cubic feet).
e. Small scale private water supply system:
A water supply facility that uses water supplied by a water supplier as the only
water source and is equipped with water tank(s) whose total effective capacity exceeds 10
cubic meters.
(2) Obligations and regulations in accordance with the type of water supply system
The Water Works Law provides the following regulations according to the type ofwater supply system.
a. Applicable to all types of water supply systems:i.

Application of drinking water quality standards:
The standards that apply to water that is supplied by a water supply system arespecified by the Ministry of Health, Labour and Welfare (MHLW).
ii.

Application of facility standards:
The technical standards that apply to water supply facilities are specified by theMHLW. These standards also include those for chemicals, such as coagulants, pH control
chemicals, and powdered activated carbon.
b. Applicable to water supply service, wholesale water supply service, and private watersupply system
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i.

Notification and inspection prior to the start of service:
Prior to the start of a water supply service, water suppliers, etc. must notify theMinister of Health, Labour and Welfare of the start of service and carry out inspections of thewater quality and facility.
ii.

Technical administrator of water service:
Water suppliers, etc. must employ a technical administrator for the water service totake charge of technical matters.
iii.

Water inspection:
Water suppliers, etc. must carry out regular and emergency water inspections tocheck the quality of the water they supply.
iv.

Health check:
Water suppliers, etc. must provide regular and emergency health checks for
employees who work at intake facilities, purification plants, or drainage basins.
v.

Hygienic measures:
Water suppliers, etc. must take hygienic measures, including disinfection of thewater by chlorine.
vi.

Emergency suspension of water supply:
Water suppliers, etc. must immediately suspend the water supply and notify related
authorities should the supplier learn of the possibility that the water being supplied is harmful
to public health.
vii.

Consignment of services:
Water suppliers, etc. may consign technical practices concerning water management
to another water supplier, the private sector, etc.
c. Applicable to water supply service and wholesale water supply servicesi.

Authorization of business operation:
Any parties who are planning to start business as providers of water supply services
must obtain authorization from the Minister of Health, Labour and Welfare. When a supplierexpands its service area, the change of business operation must be authorized by the Minister.
Authorization of water supply service and wholesale water supply services with 50,000 or
fewer customers is made by the prefectural governor concerned.
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ii.

Permission for suspension and discontinuation of service:
Water suppliers, etc. may not suspend or discontinue the water supply service
without authorization from the Minister of Health, Labour and Welfare. When a watersupplier, etc. transfers all the practices of its water supply operation to another party, it must
notify the same Minister of the transaction.
iii.

Supervision of construction by an engineer:
Water suppliers, etc. must have a qualified engineer supervise the construction ofwater facilities.
iv.

Provision of information:
Water suppliers, etc. must provide consumers with information on the plan and theresults of water quality inspections and other matters.
d. Applicable to water supply servicei.

Water supply regulations:
Water suppliers must lay down regulations concerning water supply conditions
including the water rate.
ii.

Obligation to supply water:
Water suppliers may not refuse a request for a contract to supply water from a
consumer inside its service area without a justifiable reason.
iii.

Water service installations:
Water suppliers may refuse a request for a contract to supply water when thestructure or material of the consumer’s water supply equipment or facility does not comply
with standards designated by the government ordinance. Water suppliers may appoint thebuilder of the water service installation. Water suppliers may enter the land and/or buildingsof the consumer in order to carry out inspection of the water service installation.
iv.

Request for inspection:
The water consumer may request the water supplier to conduct inspections of awater service installation and the quality of the water supplied.
v.

Installation of fire hydrants:
Water suppliers must install fire hydrants to be used for public fire-fighting
operations. (Small-scale water utilities are exempted from this regulation.)
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e. Applicable to private water supply systemsi.

Confirmation of conformity of facility standards:
Parties who are installing a private water service installation must have theprefectural governor confirm that the facility conforms to the applicable facility standards
prior to the start of construction.
f. Applicable to small scale private water supply systemsi.

Compliance with management standards:
The party who installs a facility must manage the facility in compliance with theordinance of the Ministry of Health, Labour and Welfare.
ii.

Inspection of management status:
The party who installed the facility must allow inspection of the management statusat least once a year by an organization of the local public corporation or an inspection
organization registered with the Minister of Health, Labour and Welfare.
(3) State subsidy for facility construction
The Water Works Law states that the state government may subsidize local public
corporations that provide water supply service or wholesale water supply service to cover partof their costs. The subsidies from the state government for water supply services are classified
into two types: subsidies for the development of water resources or the construction ofadvanced water treatment and other facilities by water supply services and wholesale watersupply services; and construction of facilities for small water supply service. These
government subsidy systems have promoted the spread of water service installations andsuppressed possible regional differences in water utility rates.
In fiscal 2003, approximately 150 billion yen was budgeted for these subsidies.

4. History of the legal system for waterworks(1) Enactment of the Waterworks OrdinanceIn 1890, when the Waterworks Ordinance (the “old Water Works Law”) wasinstituted, municipal governments were the only type of organization that were authorized tooperate waterworks. The government recognized that operation of drinking water service
6‑ 67 ‑installations, which had a public mission to prevent epidemics of cholera and other infectious
diseases, should not be consigned to the private sector, for it would impose a substantial
influence on the administration of hygiene. The ordinance went through five stages ofamendment, and as a result, eventually allowed non-governmental bodies to construct andoperate water service installations. In addition, a certain part of the authority of the Ministerof Home Affairs was entrusted to prefectural governors.
(2) Enactment of the Water Works Law
In 1957, the current Water Works Law was enacted after some flaws wererecognized in the old law. For example, many cases of epidemics of waterborne infectious
diseases originated from water service installations for private use, which were not covered by
the old law.
The new Water Works Law stipulates the obligations of the water suppliers in theirbusiness operation and hygiene and safety measures. It also regulates procedures for statesubsidies and the operations of wholesale water supply services and private water service
installations.
(3) Amendment of the Water Works Law
While water supply systems spread over a wide area of Japan rapidly after theenactment of the Water Works Law, some serious problems have arisen. The rapid growth inpopulation and industrial activities have imposed a large burden on the existing water supply
systems. The concentration of population in large cities and the progress of industrialization
has brought serious problems with the quality of water at its sources. Under these situations,the need for water resources development and enlargement of water supply areas has become
more clearly recognized. In response to these situations, a new state subsidy system wasestablished in the budget for fiscal 1967.
In 1977, the Water Works Law was amended to allow the following items: 1)
Prefectural governors may carry out the Water System Arrangement Plan for Wide Area
Supply at the request of the local public entities concerned, 2) water suppliers, etc. may
request the governmental institutions concerned to take appropriate measures to maintain thewater quality at its source, and 3) systems that supply water using a storage tank with a certain
size (systems in buildings that obtain their water from a water supplier, for example) aredefined as small scale private water supply systems and specific regulations apply to thesesystems.
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The amendment of the law in 1996 stipulated the licensing system for water systemconstruction companies. Until then, each water supplier could designate the construction
company for water supply facilities following the local ordinance and other regulations. In
this amendment of the law, a national licensing system was established for engineers for theconstruction of water supply facilities. This amendment allowed qualified engineers to workin water supply facility construction at the request of a supplier located anywhere in thenation.
The amendment in 2001 was made under the main theme of “enforcement ofwaterworks management systems.” It permitted the entrustment of management practices tothird parties and facilitated the procedures to merge water suppliers. A new definition, private
water supply system, was applied to water supply systems that had a high capacity but had notbeen regulated by the law. The amendment also clarified the responsibilities of watersuppliers and installers of storage tanks that are stated in water supply regulations determinedby the supplier. Disclosure of information to water consumers was also encouraged in theamendment.
In 2003, another amendment of the Water Works Law was made to introduce newprovisions on water quality inspection. Before this amendment, designation by the Minister ofHealth, Labour and Welfare had been required when a water supplier chose a water quality
inspection institution to whom to entrust their water quality inspection and inspection of themanagement status of private water supply facilities. In this amendment, however, aregistration system for such inspection institutions was introduced. Now the institutions arerequired to meet the registration standards, including items to ensure the credibility of theseinspections.
(4) Current status of water quality standards
The Waterworks Ordinance (the “old Water Works Law”) of 1890 did not include
provisions for water quality standards. In 1908, the Waterworks Council laid down the Agreed
Method of Examination as the national standard method for inspecting the water quality. In
1958, the Drinking Water Quality Standards were established based on the current Water
Works Law, which was enacted in the previous year. After amendments in 1960, 1966, and1978, the standards went through a substantial amendment in 1992. In May 2003, about 10years after the previous amendment, water quality standards were revised one more time inpart in response to the amendment to the Guidelines for Drinking Water Quality by the World
Health Organization (WHO). The latest standards have been effective since April 2004.

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5. Conclusion
For Japanese waterworks, the 20th century was an era in which its services wereextended to consumers throughout the nation. How to carry on these services in a sustainable
way is a critical challenge for waterworks in the 21st century. Specifically, sustainableoperation, including proper replacement, maintenance, and management of the existing
facilities, must be carried out as the nation’s population is decreasing rapidly. In addition,
while the spread of the water supply systems has reached 97% of the population, the rest
(approximately 4 million people) still depend on well water, which does not necessarily
supply an appropriate quality of water. Appropriate measures need to be taken especially inthese areas to improve the water quality management systems.
In June 2004, the Ministry of Health, Labor and Welfare issued their “Vision ofwater services,” a long-term plan for the nation’s water supply services. The Vision will be afundamental tool to develop governmental measures for the forthcoming years.

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