JStories ー With a inhabitants of roughly 14.25 million, Tokyo ranks among the many largest cities on this planet. But, on the subject of water assets, the metropolis is much from naturally blessed. Tokyo depends closely on rivers such because the Arakawa River, which flows via town, and the Tone River, one in every of Japan’s largest, for its water provide — sources that carry a excessive threat of flooding in the course of the wet season and are weak to different pure disasters.
And but, it’s not unusual to listen to Tokyo residents declare that town’s faucet water tastes higher than bottled water. As somebody who moved to Tokyo from China multiple 12 months in the past, I can personally vouch for this: The water that flows straight from the tap shouldn’t be solely scrumptious but in addition impressively secure.
In European cities like Vienna and Zurich, residents profit from meltwater from the Alps — pristine and naturally filtered. Tokyo, in distinction, attracts the overwhelming majority of its water from rivers, that are extra susceptible to points like algae development in summer time, resulting in disagreeable odors and cloudiness. Previously, these circumstances usually made Tokyo’s faucet water much less palatable.
However the Tokyo Metropolitan Authorities has invested closely in modernizing its water infrastructure, constructing resilient techniques designed to resist disasters and provide clear water reliably and affordably. By turning a “weak point in water sources” right into a driving drive for innovation, town has developed superior purification applied sciences which have remodeled its faucet water into one thing hardly ever seen elsewhere on this planet: river-sourced water that rivals — and, to many, surpasses — the style of bottled water.
A self-purifying system that offers the water a crisp, springlike freshness
In June of this 12 months, I visited the Higashimurayama Water Purification Plant, situated on the foot of the Tama Hills in western Tokyo. It was one of many first services within the metropolis to completely implement superior water therapy strategies — a system usually described as able to turning any water into one thing really scrumptious. There, I witnessed each the subtle purification course of that transforms uncooked river water into recent, springlike faucet water, and the dedication of the individuals who make it potential.
Superior water therapy is a three-step purification course of that builds on typical strategies by including ozonation and organic activated carbon filtration. This technique removes even probably the most persistent impurities, together with hint quantities of trihalomethanes — disinfection byproducts suspected to be poisonous or carcinogenic — in addition to disagreeable odors and natural matter.
The method begins with ozonation, the place highly effective oxidation breaks down natural compounds and odor-causing substances. The handled water then flows via a mattress of activated carbon that hosts a neighborhood of microorganisms. These microbes, cultivated and stabilized over a few years, soak up and decompose remaining natural particles, together with ammonia and metabolic byproducts from algae.
This technique doesn’t depend on further chemical substances and as an alternative mimics pure purification techniques. Not like conventional chlorine-based therapies or easy activated carbon filtration, it eliminates harsh smells and byproducts, whereas additionally giving the water a softer, smoother style.
The microorganisms nestled inside the tiny pores of the carbon granules play an important position — they fairly actually “eat” the odors, breaking down naturally occurring natural pollution like fallen leaves or organic matter carried in river water. It’s a course of that might be described as “water purifying itself” — not via aggressive disinfection, however via the quiet work of an invisible microbial workforce.
On the Higashimurayama Purification Plant, that is adopted by a closing filtration stage utilizing sand and membrane filters, which take away any remaining positive particles, additional enhancing each readability and security.
“Tokyo’s faucet water is scrumptious,” says Naoki Ueno, director of buyer companies on the Tokyo Metropolitan Authorities’s Bureau of Waterworks. “It’s broadly utilized in cooking and even in sake manufacturing. For breweries working in Tokyo, water high quality is crucial — and so they particularly select faucet water from town. In lots of international locations, the main focus continues to be on making water drinkable. However in Japan, we’ve moved past that — our aim is to make it nice to drink. That’s a degree few nations have reached.”
To assist this, town has launched the Implementation of Tokyo Excessive High quality Administration Program (the Tokyo model of the Water Security Plan). This framework ensures rigorous high quality management and builds belief via complete monitoring — from the water supply all the best way to the faucet. In an interview with JStories, Ueno commented, “Japan is likely one of the few international locations on this planet the place folks can drink water straight from the faucet — a novel cultural apply we’re dedicated to preserving.”
Past security, Tokyo gives clear, great-tasting water that’s pleasing to drink — all at a low value.
In a 2016 report by a Dutch consulting agency rating the water environments of main international cities, Tokyo positioned solely twenty fifth — primarily because of its vulnerability to pure disasters and restricted reservoir capability. On the worldwide stage, Tokyo’s water infrastructure shouldn’t be at all times thought to be top-tier.
Nonetheless, on the subject of the precise high quality of consuming water, Tokyo stands out. Many Western cities that ranked greater nonetheless rely closely on excessive concentrations of chlorine for disinfection. Whereas efficient in making certain security, this usually leaves a noticeable chemical aftertaste.
Tokyo, in contrast, takes a extra refined strategy — prioritizing not solely security but in addition taste and the general consuming expertise. The result’s water that’s clear, refreshing, and pleasing — all at a low price.
A 2018 survey performed by the Bureau of Waterworks discovered that when Tokyo faucet water was in contrast with bottled mineral water, 60% of respondents mentioned they most well-liked the faucet water or discovered it simply pretty much as good.
Tokyo’s leak prevention efforts earn international recognition
Tokyo has additionally earned worldwide reward for its efforts to forestall water leakage. Within the Nineteen Seventies, town’s leakage price was near 30%. However via regular, long-term efforts — corresponding to changing growing old pipes, introducing chrome steel piping, and implementing meticulous inspection techniques — Tokyo has succeeded in decreasing that price to one of many lowest on this planet.
“In comparison with different main cities like London, Reykjavik, Beijing, or New York, Tokyo’s leakage price is simply 3%,” says Ueno. “In different phrases, solely 3% of town’s water is misplaced — an exceptionally low determine by international requirements.”
One other defining characteristic of Tokyo’s water infrastructure is its outstanding stability. For example, town has constructed a “uncooked water interconnection” system that permits water provides to be switched between a number of rivers. Within the occasion that one supply turns into contaminated, the system can rapidly reroute provide from one other — making certain uninterrupted entry to scrub water.
Following the Nice East Japan Earthquake in 2011, Tokyo additionally started putting in earthquake-resistant pipes — a know-how hardly ever seen elsewhere on this planet. “Japan experiences frequent seismic exercise,” says Ueno. “To proceed delivering secure, high-quality water even throughout disasters, we’ve launched specifically engineered piping that doesn’t dislocate throughout earthquakes.”
Regardless of these improvements, Tokyo’s water stays inexpensive by international requirements. For a typical family utilizing a 13-mm-diameter service pipe, the month-to-month base price begins at simply 860 yen, and water utilization prices as little as 22 yen per cubic meter — which interprets to simply 0.022 yen per liter. That’s considerably cheaper than bottled water, which in Japan sometimes prices about 100 to 150 yen per liter.
In distinction, residential water charges in New York Metropolis vary from $1 to $2 per cubic meter (roughly 150 yen to 300 yen as of July 2025), with OECD averages in an identical vary — making Tokyo’s water system not solely one of the crucial resilient, but in addition among the many most cost-efficient within the developed world.
Catastrophe-Resilient, pump-free techniques: Tokyo shares its water infrastructure experience overseas
One key issue behind Tokyo’s means to ship high-quality water at low price lies in its operational effectivity and optimized power construction. At present, round 20% of the electrical energy used at Tokyo’s water purification vegetation comes from renewable sources corresponding to hydropower and solar energy. This not solely saves town roughly 50 million yen (about $320,000) in annual power prices but in addition reduces CO2 emissions by round 1,900 tons every year.
The Higashimurayama Purification Plant performs a central position on this steady provide system. Positioned on a uncommon highland inside the metropolis — at an elevation of roughly 80 meters above sea degree — the plant is designed to ship handled water to city areas utilizing gravity relatively than pumps within the occasion of an influence outage.
This pump-free supply system proves particularly invaluable throughout main disasters like earthquakes. It ensures that even in a widespread blackout, central areas of the Tokyo metropolitan area can obtain water for at the least 48 hours, reinforcing town’s resilience and catastrophe preparedness.
With its superior applied sciences and operational know-how, Tokyo stands as one of many world’s main cities in water administration — and it has been actively sharing its experience with different city facilities dealing with related challenges.
For the reason that Nineteen Eighties, the Tokyo Metropolitan Authorities’s Bureau of Waterworks has collaborated with the Japan Worldwide Cooperation Company (JICA) to welcome greater than 1,300 water professionals from over 60 international locations. These coaching applications have lined a variety of matters, together with water high quality administration, energy-efficient operations, and utility administration.
At present, Tokyo’s international engagement continues to broaden. Town has signed a leakage management partnership with Ahmedabad in western India, and has dispatched consultants to Kigali, the capital of Rwanda, to assist native water therapy plant operations. In 2024, Tokyo initiated a proper alternate with New York Metropolis, specializing in catastrophe resilience, energy-saving practices, and infrastructure renewal.
At first look, Tokyo’s faucet water could seem unremarkable. However every drop displays a long time of technological innovation and operational effort — a response to town’s useful resource constraints, environmental pressures, and the expectations of its residents. It could not come from mountain springs, however it embodies a unique form of purity: reliably clear, scrumptious water formed by the ingenuity of an city metropolis. And in that sense, Tokyo’s system gives a invaluable mannequin for cities world wide.
Translated by Mizuki Nakagawa | JStories
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