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A Cutting-edge Urban Water Supply Model

Japan has a safe, delicious, and stable water supply that can be drunk directly from the tap.

Japan has a safe, delicious, and stable water supply that can be drunk directly from the tap.

In Japan, you can drink delicious tap water safely anytime, anywhere. Japan's water supply is hailed as a cutting-edge urban water supply model due to its excellent water quality control system, which uses the latest devices; the high level of safety; and the great taste. How is this tap water made safe to drink?

Making Water Safe to Drink

Water collected from rivers is transported to a water-treatment plant, where it passes through various processes and inspections to produce water that is safe to drink. The cleaning technology is constantly evolving, and currently highly refined water is processed using ozone and activated charcoal, in addition to the regular cleaning processes.

Ozone is a very powerful disinfectant gas, and when it is passed through the water, it dissolves the substances that cause noxious odors. There are countless small pores in the activated charcoal, and the dirt in the water sticks to them. Furthermore, the source of the dirt is eliminated by the simultaneous dissolving action of the microorganisms that breed in the activated charcoal. Thanks to these processes being carried out thoroughly, Japanese water does not have unpleasant odors nor does it taste of mold or disinfectant.

Sedimentary basin in a water-treatment plant. This is where floating contaminants in the water are made to sink. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

Sedimentary basin in a water-treatment plant. This is where floating contaminants in the water are made to sink. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

In addition, scrupulous water quality inspections are performed at each stage of the water-purification process. There are also poison-detection tanks that utilize fish monitoring using CCTV, and the electrical signals generated when fish move their muscles are measured constantly. If the water is contaminated, the fish exhibit strange behavior, such as moving suddenly, alerting workers at the water-purification plant instantly and enabling them to initiate changes to the purification process.

To identify the condition of the rivers that constitute the water source and to promptly identify water contamination, water-testing vehicles are used to implement periodic patrols, and to measure water quality and monitor the situation. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

To identify the condition of the rivers that constitute the water source and to promptly identify water contamination, water-testing vehicles are used to implement periodic patrols, and to measure water quality and monitor the situation. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

Delivering Fresh Water

Japan uses various methods to deliver filtered water based on thorough water quality control during the cleaning process. Despite these best efforts, clean water is useless if the pipes leak and the water does not reach the tap. Consequently, the focus is on inspecting and repairing the pipes in a planned manner.

There is a constant risk of worn pipes leaking due to deterioration of the materials over time and the vibrations caused by traffic. Not only must worn pipes be replaced, but they must be replaced with pipes that can resist earthquakes, therefore the aim is to create facilities that can cope in the event of a disaster.

Furthermore, many buildings and apartments use water tanks, but if their interiors become dirty, the water quality may suffer. For this reason, the facilities are inspected periodically, and the water tanks are cleaned once a year, to maintain water quality. Meanwhile, direct pipe connections are being introduced in low-rise buildings where a fixed water pressure can be assured, such as regions with high water pressure in the pipes and where the diameter of water pipes is large. This method supplies water directly using the water pressure in the pipes, and compensates for insufficient water pressure by using pumps to increase the water pressure. Water tanks are not used, so delicious water can be delivered to your home with the water quality retained exactly as it is at the treatment plant.

The water tank piping method fills a water tank with water, and then uses a pump to suck up and supply water to tanks installed high up on rooftops.

The water tank piping method fills a water tank with water, and then uses a pump to suck up and supply water to tanks installed high up on rooftops.

The direct water supply method sends water to the tap using the pressure in the pipes. A pressurization pump may be used to supplement insufficient water pressure.

The direct water supply method sends water to the tap using the pressure in the pipes. A pressurization pump may be used to supplement insufficient water pressure.

Filtered Water is also Sold in Plastic Bottles

Tokyo water on sale in plastic bottles and available from supply wagons set up at event locations. Try some. You'll be surprised at the taste. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

Tokyo water on sale in plastic bottles and available from supply wagons set up at event locations. Try some. You'll be surprised at the taste. (Photo courtesy of the Bureau of Waterworks Tokyo Metropolitan Government)

To enable even more people to enjoy our delicious water, it can be sampled at our water wagons set up at event venues, or it can be purchased in bottles. This is only possible because of our absolute confidence in the taste and safety of our water. If you ever visit Japan, make sure to drink our water and experience its delicious taste.

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