イタリア産天然溶岩石を使った溶岩ホットヨガスタジオ「オンザショア」

イタリア産天然溶岩石を使った溶岩ホットヨガスタジオ「オンザショア」

Tachikawa Water History: Where the Tap Water Comes From, and Wells

多摩湖村山貯水池の水面東村山浄水場の水源のひとつで岸の林と青空が映っている 立川駅徒歩1分年中無休の溶岩ホットヨガスタジオ

From a town water supply to Tokyo’s: Tachikawa’s water in the Showa era

Pick out only the water entries from the City of Tachikawa’s chronology and another post-war history appears.

1951: Tachikawa City begins its water supply. 1958: Sunagawa town begins its water supply. 1961: Tachikawa City begins its sewerage. 1970: the Northern purification plant is completed, and the same year the district name Sakaecho is born. Today, Tokyo’s Tachikawa Sakaecho purification station stands in Sakaecho. Whether the two are the same facility’s history, I could not confirm from the documents. That question I will leave in the reader’s hands.

By the early 1960s, Tama’s water was nearing its limit. According to the encyclopedia’s entry for the Ozaku purification plant, in 1963 the three Tama districts had 856,000 people on the supply, a coverage rate of 64.1 per cent, and peak daily distribution had grown about 2.3 times in just the three years since 1960. Most of the water for drinking and industry was groundwater pumped from wells, but as the population soared, towns and factories dug too many deep wells; the water table in Tama, already low, fell, and the amount that could be drawn kept shrinking.

The Bureau of Waterworks explains this period as follows. Japan’s Water Supply Act says that, in principle, water supply is run by municipalities, and in Tama each city and town ran its own system. But to deal with severe shortages caused by the rapid population growth from the early 1960s, and to correct the gaps in price and coverage between the 23 wards and the Tama municipalities, the systems were unified into a Tokyo-run supply at the municipalities’ request. The Ozaku plant was built to supplement Tama’s water and was completed in June 1970.

The City of Tachikawa’s chronology records under 1981: “Agreement with Tokyo on unification of the water supply.” For a long time after that, the municipalities still did the water work on Tokyo’s behalf, but at the end of fiscal 2011 all of it passed to Tokyo. Today the Tokyo Metropolitan Bureau of Waterworks runs the water supply of 26 Tama cities and towns — all except Musashino, Akishima, Hamura and Hinohara. As I wrote in the Akishima article, neighbouring Akishima still has its own water supply, drawn entirely from deep groundwater.

And the control tower of Tama’s water supply is in Tachikawa. According to the Bureau of Waterworks, its single Tama Water Supply Reform Promotion Headquarters is in Tachikawa. One of the three water-supply management offices that serve as bases for managing the facilities is also in Tachikawa. The Tachikawa Service Station, the counter for charges and works, is in Midori-cho, Tachikawa, covering Tachikawa, Kokubunji and Kunitachi. In the city whose wells became undrinkable in 1952, there is now the headquarters that binds together the water supply of 26 Tama cities and towns.

Then and now

Then: in some Tachikawa homes, people faced wells that smelled of petrol and waited for a water truck that came only at certain hours. Now: Tone and Tama River water reaches Tachikawa’s taps, sometimes mixed with water from deep wells underfoot, and the Tama headquarters that runs that supply is in Tachikawa.

Tachikawa’s water by the numbers

  • 80 — per cent of Tokyo’s water that comes from the Tone and Arakawa systems. In Tokyo’s water supply, the Tama River is surprisingly a supporting player.
  • 24 — public-supply source wells in Tachikawa on Tokyo’s fiscal 2020 list. Shibasaki alone goes up to No. 9.
  • 30–40 — shaku: the depth of the wells that smelled of petrol in 1952. About 9 to 12 metres.
  • 230 — litres per person per day: the supply assumed in Tachikawa’s 1952 water plan.
  • 3 — litres per person per day: the guideline for water handed out at disaster water stations. That is 3 kilograms.
  • 825 — tonnes of drinking water Tachikawa City stockpiles at evacuation shelters and elsewhere.

The wanderer’s quiz

In its 1953 written answer, besides petrol from the US forces’ base, what did the government newly name as a suspected cause of the polluted wells in Tachikawa? (A) Floods on the Tama River; (B) underground petrol tanks of the former Imperial Japanese Army; (C) factory waste water. The answer comes at the end.

The last two numbers on that list, 3 litres and 825 tonnes, are numbers for a day of disaster. Tachikawa’s water story also reaches into emergencies yet to come.

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Water on a day of disaster: water stations, and 20 tonnes under the schoolyard

If an earthquake cuts off the water, where can you get some?

The Bureau of Waterworks calls the places that hand out water during a cut-off “disaster water stations”. The aim is one within roughly 2 kilometres of every home, set up at 213 purification plants, supply stations and emergency water tanks across Tokyo. After an earthquake, water is handed out on the guideline of 3 litres — the amount of drinking water an adult needs per day. Across all its facilities, including the tanks storing water under parks, Tokyo has secured drinking water for its roughly 14 million residents for more than about three weeks, at 3 litres per person per day.

On Tokyo’s list as of 1 November 2025, Tachikawa has four disaster water stations: the Shibasaki supply station in Shibasaki-cho 1-chome, the Tachikawa Sakaecho purification station in Sakae-cho 5-chome, the Tachikawa Sunagawa supply station in Sunagawa-cho 6-chome, and the city’s Matsunaka Park in Nishisuna-cho 1-chome. Facilities that pump up well water every day become, in an emergency, places that hand water to the neighbours.

A park’s emergency water tank is not just a tank. According to the Bureau of Waterworks, it is connected to the water mains so that its water keeps being replaced, and when an earthquake strikes, the flow in and out is shut off to protect the drinking water inside. Water that is always flowing is, for that one day, held quietly under the park. Tokyo writes that its water facilities are ready to open even at night and on holidays. Their status will be announced on the Bureau’s website and app, by loudspeaker vans and leaflets, and on Tokyo radio stations. The water truck of 1952 came only at certain hours. The water stations of today are prepared on the assumption that they will open at night and on holidays.

One warning. Containers are not provided at the water stations. The Bureau of Waterworks points out that 3 litres means 3 kilograms, which is heavy, and asks you to prepare a water bag you can carry on your back, or empty plastic bottles and a rucksack. Picture yourself carrying 3 kilograms in one hand for 2 kilometres, and your spirit may break before your arm does. A water bag, it seems, is something to buy before the earthquake.

Tachikawa City keeps its own water, too. According to the city, each of its 29 elementary and junior high schools that serve as primary evacuation shelters, plus Tachikawa Sozosha (the former Tamagawa Elementary School), stores 20 tonnes of drinking water. With stocks at the city gymnasium, the shared school-lunch kitchen and elsewhere, the total is 825 tonnes. And for cases where the water main survives but the pipes into buildings are broken, standpipes and other equipment for drawing water from roadside fire hydrants have been issued to 30 citizens’ disaster-prevention groups and every primary shelter.

The city also has 44 “dual-use disaster wells”, which water the fields in ordinary times and give neighbours water for washing and other daily needs in a disaster — as I wrote in the farm article. Showa-era Tachikawa had its wells polluted and asked for mains water. Present-day Tachikawa keeps wells for when the mains stop. Over seventy years, wells and the water supply have become each other’s spare.

For ordinary days, there is a pleasure too. The Bureau of Waterworks calls the drinking fountains where you can fill a water bottle with tap water “Tokyowater Drinking Stations”, and publishes a list. In Tachikawa it listed six: the Tachikawa Disaster Prevention Education Center (Tachikawa Bosaikan); the Women’s Center “I’m” and the Central Library in Faret Tachikawa Center Square; the Tachikawa City General Welfare Center; the Bureau’s Tama Water Supply Tachikawa building; and Wakaba Library. On your walk, you can take a sip of Tachikawa water. Which well and which river it came from, only the far side of the tap knows.

Answer to the quiz

The answer is (B). The written answer of 10 March 1953 says the cause had been thought to be petrol seeping into the ground from the US forces’ base, but recently suspicion had arisen that it was also leaking from underground petrol tanks for the former Imperial Japanese Army. Under Tachikawa, the fuel of two eras lay sleeping.

yogaのレッスン前の様子生徒の足もとにあるヨガマット 立川駅徒歩1分年中無休の溶岩ホットヨガスタジオ

Before you go

  • The water facilities are not for visiting: the Shibasaki supply station (1-1-41 Shibasaki-cho, Tachikawa), the Tachikawa Sakaecho purification station (5-38-5 Sakae-cho) and the Tachikawa Sunagawa supply station (6-41-1 Sunagawa-cho) are working water facilities, and you cannot normally go inside. Remember where they are as disaster water stations. Tokyo’s list (Japanese): https://www.waterworks.metro.tokyo.lg.jp/kurashi/shinsai/ichiran
  • Finding your nearest water station: the Bureau of Waterworks says its “Tokyo Waterworks App” shows water points in order of distance from where you are, and during a disaster shows whether they are open: https://www.waterworks.metro.tokyo.lg.jp/kurashi/shinsai/kyoten
  • For a sip of Tachikawa water: the Tachikawa Bosaikan (1156-1 Izumi-cho, Tachikawa). Take a bus from stop 1 at the North Exit of JR Tachikawa Station to “Tachikawa Shobosho” (Tachikawa Fire Station); it is right by the stop. Or walk 15 minutes from Takamatsu Station on the Tama Monorail (according to the Tokyo Fire Department). Check how to visit and closing days on the official site: https://www.tfd.metro.tokyo.lg.jp/taiken/tachikawa/index.html — the Central Library in Faret Tachikawa Center Square also has a drinking station (list: https://www.waterworks.metro.tokyo.lg.jp/documents/d/waterworks/103003-25-02).
  • Tachikawa City’s stockpiles and water supply in a disaster (Japanese): https://www.city.tachikawa.lg.jp/bosai/m-bosai/1008366/1008399.html
  • Getting there: From central Tokyo, take the JR Chuo Line from Shinjuku to Tachikawa without changing. From Kanagawa, the Nambu Line runs from Kawasaki to Tachikawa without changing.
  • Practical tips: Carry an IC transport card such as Suica or PASMO; it works on JR, the monorail and buses. Bring a refillable bottle for the drinking stations. If you are staying in Tokyo for a while, it is worth knowing your nearest disaster water station.
  • Combine it with: the Tachikawa Regional Disaster Prevention Base next to the Bosaikan (our disaster-prevention article); the Tamagawa Aqueduct and the Sunagawa branches (the aqueduct article); and the springs below the bluff (Nekawa and the Tama River, Yagawa and the hake).

Some weekend, take the Chuo Line from Shinjuku to Tachikawa, have a sip of water at the Bosaikan, and remember that twenty-odd wells lie sleeping beneath the city. That alone will make Tachikawa’s water taste a little different.

At the North Exit of a water town

Walking while reading about water makes you thirsty — all the more if you go round checking the water stations one by one.

One minute’s walk from the North Exit of Tachikawa Station, on the third floor of the Etoile Building at 2-14-10 Akebonocho, Tachikawa, is On the Shore Tachikawa (オンザショア立川店), a hot yoga studio heated by lava-stone plates. As well as lava-stone hot yoga, it offers room-temperature yoga, Pilates, women-only kickboxercise, boxercise, HIIT and personal training, with more than 25 kinds of yoga lesson.

It is open every day from 8:00 to 23:30, the same hours whatever the day. On the way back from a drink of water at the Bosaikan, or after an evening walk, there is time to drop in.

A trial yoga lesson costs ¥1,980 including tax, with two bath towels, one face towel and a yoga mat included in the rental. After you have sweated, a glass of water. You can come with nothing but yourself.

Pregnant guests cannot take part in lava-stone hot yoga, but room-temperature maternity yoga is available.

Many of our yoga instructors speak English, and the studio’s owner, Naomi Fujita — who holds Eiken Grade 1, Japan’s top English qualification, and a perfect TOEIC score, worked as a translator and overseas interpreter at Nomura Securities, and lived in Alaska for three years — often helps guests from the US bases in English herself. Overseas guests have praised the English support in their Google reviews. If you would like help in English, just mention it when you book.

Studio information: https://ontheshore.jp/ — prices: https://ontheshore.jp/price/ — trial lesson booking: https://site.locaop.jp/C0aVK?_src=hp

Every time I hear water falling from the tap, I still think, just a little, about the wells far beneath my feet.

Cover photo: Lake Tama (Murayama Reservoir), one source of the Higashimurayama plant, reflecting wooded shores and blue sky. (Photo: Guilhem Vellut from Annecy, France / CC BY 2.0 / Wikimedia Commons)

Information as of October 2026.

More Tachikawa Walks

All Tachikawa Walks (English)

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