Kumamoto City Waterworks Memorial Hall (former Hakenomiya Reservoir Pump Station)

A Brick Box with a Strange Roof

The Kumamoto City Waterworks Memorial Hall, formerly the Hakenomiya Reservoir Pump Station (熊本市水道記念館・旧八景水谷貯水池ポンプ場, also written Hakenomiya or Hake-no-miya), stands beside the springs of Hakenomiya in Kita Ward, Kumamoto City, was completed in 1924, and was entered on Japan's national register of Tangible Cultural Properties in May 1997.

The plan is a square. One storey, brick, ninety-nine square metres of floor area. Nothing about that description prepares you for the roof.

A hipped roof covers the building, and from each of its four faces a small subsidiary roof pushes outward, built up from reverse curves. The result reads as neither Japanese nor conventionally Western. Below it, brick walls carry mortar-rendered surfaces along the upper part, so the building is banded horizontally in two materials and two colours. Window openings are picked out with raised borders.

The national database calls the effect Expressionist dress. That is a fair label. Expressionism in architecture, the German current of the years around 1920, went in for distorted geometry and for making structure look as though it were under pressure from within. A municipal pump house in provincial Kyushu is an unlikely place to find it, and that mismatch is much of the pleasure.

The City That Drinks Only Groundwater

Kumamoto began piped water supply on 27 November 1924, the same year this building went up. From that day to this, every drop of the city's tap water has come from groundwater. No city of comparable size in Japan supplies more than half a million residents entirely from underground sources.

Hakenomiya is where that story starts. The springs here are abundant enough to have supported a Hosokawa lord's teahouse in the Edo period, and the place name is generally explained as a compound of hake, a local word for a spot where valley water emerges, with the eight scenic views the lord is said to have composed there. Four wells now draw from the aquifer beneath the park.

Water does not climb a hill on its own. Kumamoto's system lifts it from Hakenomiya to a distribution reservoir on Mount Tatsuta, and from there gravity carries it into the city centre. Pumping is the expensive, indispensable middle step, and this building housed a pump.

Accounts published by local sources describe the building as the second delivery pump room of the Hakenomiya source, working from the founding of the system in 1924 until March 1967, a run of forty-three years. The Agency for Cultural Affairs registers it under the name Hakenomiya Reservoir Pump Station. The two names describe the same structure and the same function from slightly different angles.

Its registration number is 43-0004, from the second round of registrations nationwide. That is worth pausing on. The register opened in 1996; this building was among the earliest properties in Kumamoto Prefecture accepted onto it, formally registered on 7 May 1997 with public notice on 29 May. The criterion applied was contribution to the historic landscape of the nation.

Inside, and How to Get There

Local accounts describe an interior of white plaster and a ceiling higher than the exterior leads you to expect, so the single room feels larger than ninety-nine square metres. At roughly the centre stands a delivery pump with its motor, reported to be Swiss machinery by Sulzer Brothers, left in place from the system's founding. Photographs and captions around it cover the early years of Kumamoto's water supply.

Access to that interior is the sticking point. The building opens on a limited basis, chiefly during events, and it also appears on the guided facility tours that the Kumamoto City Water and Sewerage Service Corporation arranges for groups and schools. There is no walk-in visiting and no posted opening hours. Groups can enquire through the corporation; individuals are better off timing a visit to a public event.

The exterior costs nothing and asks no permission. It sits within Hakenomiya Park, which is open ground with around two hundred Yoshino cherry trees, streams, and a bronze statue of Katō Kiyomasa moved here after a 1925 exposition marking the city's water supply, tram line, and garrison relocation. The nearest station is Hakenomiya on the Kumamoto Electric Railway Kikuchi Line, an unstaffed halt a short walk away.

Combine the visit with the Kumamoto City Water Science Museum at 1-11-1 Hakenomiya, a separate and much newer building a few minutes further on. Admission is free, hours are 9:00 to 17:00, and it closes on Mondays. That museum was shut after the earthquake of 28 July 2026 and reopened on 1 August 2026.

The earthquake, magnitude 7.1, was centred well south of here, and no damage to this registered building has been reported. Kumamoto City's northern wards recorded strong but not extreme shaking. Since facility schedules across the prefecture are still being revised, check before travelling.