The Yonai Water Purification Plant Waterworks Memorial Hall

The Yonai Water Purification Plant Waterworks Memorial Hall (米内浄水場水道記念館, Yonai Jōsuijō Suidō Kinenkan) is a single-storey timber building erected in 1934 as the administration office of the Yonai Water Purification Plant in Kamiyonai, Morioka City, Iwate Prefecture, and listed as a Registered Tangible Cultural Property on 23 August 1999. Registered as No. 03-0019, it has a tiled roof and a building area of 157 square meters, and it is the only timber building among the eight listed structures at the plant.

According to the Morioka waterworks bureau, it was built as the plant's office and the caretaker's home when the water supply opened. In 1984, for the 50th anniversary of the city waterworks, it became the Waterworks Memorial Hall, with displays on the history of Morioka's water supply. It is also covered by the city's landscape listing.

Architecture of the Yonai Water Purification Plant Waterworks Memorial Hall

The Agency for Cultural Affairs notes that the Yonai Water Purification Plant Waterworks Memorial Hall stands toward the southeast of the grounds, where it overlooks the sedimentation basin, the filters and the rest of the plant. Its plan is a squared U, with wings projecting forward on both sides of the front. The hipped tile roof (Yosemune-zukuri) carries a dormer window at the center of the façade, and the use of scratch tile is singled out as typical of the period.

The commanding position presumably let the office staff keep an eye on the basins. Morioka City describes the symmetrical front and the overall look as strongly marked by the modern eclectic style of the early Showa period.

The records disagree on the finish. The city's landscape survey gives the walls as mortar with a lithin (textured render) finish and some washed artificial stone, and does not mention scratch tile. The city also records that the exterior was restored in 1986, faithfully to the original apart from a new entrance canopy with supporting posts.

Inside and around the Yonai Water Purification Plant Waterworks Memorial Hall

Stand in front of the Yonai Water Purification Plant Waterworks Memorial Hall first. Because the two wings come forward, the central entrance sits a step back, and the dormer rising from the middle of the hipped roof marks the axis of the symmetrical front.

The displays are arranged around three characters associated with water: 源 (source), 澄 (clarity) and 涵 (nurture). The first section shows the building's own design drawings and a 1928 map of Morioka, in the room that served as the original office. The second uses photographs to show how the waterworks were built when there were few machines and poor roads. The third covers the protection of the forests that feed the river and the cherry trees planted to mark the founding of the waterworks.

A ramp gives step-free access, and there is a multipurpose toilet beside the car park.

Visiting the Yonai Water Purification Plant Waterworks Memorial Hall

For the Yonai Water Purification Plant Waterworks Memorial Hall, the waterworks bureau lists an opening season from 16 April to 30 November, 9:30 a.m. to 4:30 p.m. (with some exceptions), closed on Saturdays, Sundays and public holidays. Admission is free, but visitors are asked to apply in advance by calling 019-667-2280. Since the plant grounds are otherwise closed, book ahead and confirm the arrangements.

The hall also opens during the spring cherry blossom opening. In 2026 that ran from 22 April to 6 May, with the grounds open from 9:00 a.m. to 4:30 p.m. and the hall until 4:00 p.m. No photography policy for the interior is published, so ask the staff. The nearest station is Kami-Yonai on the JR Yamada Line, about a 2-minute walk from the plant gate.

📍 Plan Your Visit to Iwate
Find tours, activities & transport passes near Yonai Water Purification Plant Waterworks Memorial Hall
Klook.com

Q&A

QWhat was the Yonai Water Purification Plant Waterworks Memorial Hall originally?
AIt was built in 1934 as the plant's administration office and the caretaker's home, and became the Waterworks Memorial Hall in 1984 for the 50th anniversary of Morioka's water supply.
QWhat are the architectural features of the Yonai Water Purification Plant Waterworks Memorial Hall?
AA single-storey timber building with a hipped tile roof, a squared U-shaped plan with wings projecting at the front and a dormer at the center of the roof. The Agency for Cultural Affairs notes its scratch tile as typical of the period.
QWhat can you see inside the Yonai Water Purification Plant Waterworks Memorial Hall?
ADisplays under three themes: source, clarity and nurture. They include the building's design drawings, a 1928 map of Morioka, photographs of the original construction work and material on forest protection and the plant's cherry trees.
QWhat are the opening hours and admission for the Yonai Water Purification Plant Waterworks Memorial Hall?
AThe bureau lists weekdays from 16 April to 30 November, 9:30 a.m. to 4:30 p.m., with some exceptions. Admission is free, and visitors should apply in advance.
QWhen was the Yonai Water Purification Plant Waterworks Memorial Hall registered?
AIt was listed as a Registered Tangible Cultural Property on 23 August 1999, as No. 03-0019. It is the only timber building among the eight registered structures at the plant.

Basic Information

NameYonai Water Purification Plant Waterworks Memorial Hall
Location49 Nakai, Kamiyonai, Morioka City, Iwate Prefecture
DesignationRegistered Tangible Cultural Property (building)
Year DesignatedRegistered 23 August 1999 (Heisei 11)
Quantity1 building
DimensionsSingle-storey timber building, tiled roof, building area 157 square meters
OwnerMorioka City Waterworks Manager
Public AccessOpen on weekdays 16 April to 30 November (9:30 a.m. to 4:30 p.m., free, advance application required); also open during the spring cherry blossom opening

References

Database of National Cultural Properties: 米内浄水場水道記念館 (Agency for Cultural Affairs)
https://kunishitei.bunka.go.jp/bsys/maindetails/101/00001221
Cultural Heritage Online: 米内浄水場水道記念館
https://online.bunka.go.jp/heritages/detail/138491
Waterworks Memorial Hall (Morioka City Waterworks and Sewerage Bureau)
https://www.morioka-water.jp/about/kinenkan.html
Landscape Important Building: Yonai Water Purification Plant (Morioka City)
https://www.city.morioka.iwate.jp/kanko_sports_bunka/rkeishi_bunkazai/kenzobutsu/1009401.html
Press release: public opening of the Yonai plant cherry trees, 13 April 2026 (Morioka City, PDF)
https://www.city.morioka.iwate.jp/_res/projects/default_project/_page_/001/056/053/0413josui.pdf

Last verified: 2026.10.02