A Brick Shelter Over a Well, Built in 1915
The Distribution Well Shelter at the Nishiya Purification Plant Reservoir (横浜市西谷浄水場配水池配水井上屋, Yokohama-shi Nishiya Jōsuijō Haisuichi Haisuisei Uwaya) is a small brick structure of 1915 at Kawashimachō in Hodogaya Ward, Yokohama City, Kanagawa Prefecture, registered as a National Registered Tangible Cultural Property on 12 June 1997.
An uwaya is a shelter, the housing built over a piece of machinery or an opening that needs protecting. This one covers the distribution well of the plant's reservoir, the point at which treated water leaves storage for the mains. It is a working component of the water supply, not a pavilion, and it has been doing the same job since Yokohama's second waterworks expansion completed the Nishiya plant in Taishō 4.
Yokohama has reason to care about this. Japan's first modern waterworks opened here in 1887, and the Nishiya plant, drawing today from Lake Sagami, still supplies most of Tsurumi, Kanagawa, Nishi, Naka, Minami and Hodogaya wards. Six brick shelters from the 1915 works survive on the site: four over the filter bed regulating chambers, one over the purified water well, and this one over the distribution well.
The design is credited to the Yokohama City Waterworks Provisional Works Department, which is to say it was drawn in-house by municipal engineers rather than commissioned from an architect.
Octagonal, and a Question of Twenty-Two or Thirty
The reservoir has a shelter at each end. The purified water well shelter stands at the eastern end of the axis running through the four filter bed shelters; the distribution well shelter sits opposite it across the reservoir. The register describes the two as matching in form and scale, and describes the purified water shelter as octagonal in plan and a size larger than the filter bed shelters, which are square and about 13 square metres each.
Brick walls, a copper-sheet roof, single storey. The filter bed shelters use a distinctive hōgyō pyramidal roof over a square plan, and the pair at the reservoir carry the same architectural language at larger scale. White banding runs through the brickwork. Nothing here is monumental, and that restraint is precisely what registration recognised, under the criterion of contributing to the historic landscape of the country, registration number 14-0007.
The size figure is contradictory. The register's structural field gives a building area of 30 square metres; the commentary attached to the same entry gives 22. Both appear on the same database page and neither has been amended. A visitor standing in front of the building has no way to resolve it, and the discrepancy is worth flagging rather than smoothing over.
The plant grounds themselves were laid out on geometric, garden-like lines, and the register repeatedly returns to that point: the value lies in the ensemble, the small brick shelters distributed across an ordered landscape, rather than in any one of them alone. The 1973 modernisation works retired the original function of the six shelters, and the arrangement around them was kept.
Open Since July 2026
For years the position was discouraging. The Yokohama Waterworks Memorial Hall at the plant entrance closed permanently on 30 September 2021, and site tours were suspended when the plant redevelopment project began in the 2021 fiscal year, a programme scheduled to run to 2034. The registered shelters stood inside a restricted zone, viewable at a distance from behind a fence.
That changed on 27 July 2026. Yokohama City Waterworks Bureau opened an information centre at the plant, and at the same time released all six of the 1915 historic structures for public viewing.
The practical details, from the bureau's own announcement: admission is free and no reservation is required. Opening hours are 10:00 to 12:00 and 13:00 to 15:30 on weekdays, with closure at weekends and on public holidays, over the Obon period and at New Year. Group visits should be arranged in advance with the Redevelopment Promotion Section of the Facilities Improvement Division on 045-337-0870. The centre itself covers the history of Yokohama's water supply and the current works, with a VR headset offering a view inside construction areas that cannot otherwise be entered.
Access is by bus. Take the Sōtetsu Line to Hoshikawa Station, then a Sōtetsu bus on the Hama 16 or Hama 19 route to the Jōsuijō-mae stop, which is at the gate. Walkers sometimes approach instead from Kamihoshikawa Station up the slope known as Suidōzaka, the water road, so called because the mains run beneath it; partway up stands the former Kawashimachō water metering chamber shelter of 1914, itself a registered property and open as a small park.
Because these arrangements were announced only weeks ago and the plant remains a construction site, confirm the current position with the bureau before making the trip.
- 📍 Plan Your Visit to Kanagawa
- Find tours, activities & transport passes near Yokohama City Nishitani Water Purification Plant Water
- [ Kamakura Buddha Hakone Onsen & Yokohama Tours ]
Q&A
- Can the Nishiya Purification Plant distribution well shelter be visited, and what are the opening hours?
- Yes, since 27 July 2026. The six historic structures of 1915 were opened to public viewing when Yokohama City Waterworks Bureau launched an information centre at the plant. Admission is free with no reservation needed, and hours are 10:00 to 12:00 and 13:00 to 15:30 on weekdays, closed at weekends, on public holidays, over Obon and at New Year.
- How do I get to the Nishiya Purification Plant?
- Take the Sōtetsu Line to Hoshikawa Station, then a Sōtetsu bus on the Hama 16 or Hama 19 route, alighting at the Jōsuijō-mae stop directly at the plant. The address is 522 Kawashimachō, Hodogaya Ward, Yokohama.
- Why was the Nishiya Purification Plant distribution well shelter registered as a cultural property?
- It was registered on 12 June 1997 under the criterion of contributing to the historic landscape of the country. The register describes it as a small but finely composed brick shelter that has become a commemorative presence within the plant, matching the purified water well shelter across the reservoir in form and scale.
- Is the Yokohama Waterworks Memorial Hall at Nishiya still open?
- No. It closed permanently on 30 September 2021 in connection with the plant redevelopment project. The information centre that opened on 27 July 2026 stands beside the former memorial hall and now serves that function.
- How large is the Nishiya distribution well shelter?
- The national register is inconsistent. Its structural field gives a building area of 30 square metres and its commentary gives 22. It is a single-storey brick structure with a copper-sheet roof, octagonal in plan and one size larger than the four square filter bed shelters of about 13 square metres each.
- What else at the Nishiya Purification Plant is a registered cultural property?
- Six structures of 1915 in total: four filter bed regulating chamber shelters, the reservoir purified water well shelter and this distribution well shelter, all registered in June 1997. The former Kawashimachō water metering chamber shelter of 1914, about 500 metres down the hill, is separately registered.
Basic Information
| Name | Distribution Well Shelter, Nishiya Purification Plant Reservoir, Yokohama / 横浜市西谷浄水場配水池配水井上屋 |
|---|---|
| Location | 522 Kawashimachō, Hodogaya Ward, Yokohama City, Kanagawa Prefecture |
| Designation | National Registered Tangible Cultural Property (Structure), registration number 14-0007; criterion: contributes to the historic landscape |
| Year Designated | Registered 12 June 1997; gazetted 24 June 1997 |
| Quantity | 1 building |
| Dimensions | Brick, single storey, copper-sheet roof, building area 30 m² (register field); the register commentary gives 22 m². Octagonal plan. |
| Owner | Yokohama City Waterworks Administrator |
| Public Access | Open since 27 July 2026. Free, no reservation. Weekdays 10:00–12:00 and 13:00–15:30; closed weekends, public holidays, Obon and New Year. |
| Built | 1915 (Taishō 4), Yokohama waterworks second expansion; design by the Yokohama City Waterworks Provisional Works Department |
References
- National Cultural Properties Database, Agency for Cultural Affairs — Distribution Well Shelter, Nishiya Purification Plant Reservoir
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00000194
- Cultural Heritage Online — Distribution Well Shelter, Nishiya Purification Plant Reservoir
- https://online.bunka.go.jp/heritages/detail/113074
- City of Yokohama — Nishiya Purification Plant, Facility Overview
- https://www.city.yokohama.lg.jp/kurashi/sumai-kurashi/suido-gesui/suido/suishitsu/josuijo/nishiya/gaiyou.html
- City of Yokohama, press release of 21 July 2026 — Information Centre to Open at the Nishiya Purification Plant
- https://www.city.yokohama.lg.jp/city-info/koho-kocho/press/suidou/2026/0721info.html
- City of Yokohama — Tours of Purification Plants and Related Facilities
- https://www.city.yokohama.lg.jp/kurashi/sumai-kurashi/suido-gesui/suido/torikumi/PR/kengaku.html
Last verified: 2026.08.14