Page Top

Start Content

Ochiai Water Reclamation Center

Photo:Ochiai Water Reclamation Center

Located very close to the subcenter of the Shinjuku area, Ochiai Water Reclamation Center is environment-friendly and thoroughly controlled as a water reclamation center surrounded by residential districts. The treatment area is in the Ochiai Treatment District (3,506 ha). It comprises Nakano-ku, and parts of Shinjuku, Setagaya, Shibuya, Suginami, Toshima and Nerima Ward.

The treated water is discharged to Kanda River, with some part used effectively for toilet water in buildings of Nishi-shinjuku and Nakano-sakaue districts and for restoration of streams in three rivers which nearly dried up in the southern downtown area of Tokyo.

The generated sludge is pumped through pressure pipelines to Tobu sludge plant for treatment.

graph:Water quality of Kanda River

Treatment area map

(April, 2020)

Operation started March 1964
Site area 85,143m2
Treatment capacity 450,000m3/day
Wastewater treatment facilitiesGrit chamber 8
Primary sedimentation tank 10
Reaction tank 10
Secondary sedimentation tank 12
Sand filtration tank 33
Storage tank in wet weather 10,260m3

Average quality of intfluent and final effluent

The quality of water discharged from the plant complies completely with the water quality standards of the Tokyo Metropolitan Environmental Security Ordinance and is sufficiently clean for the fish to live in.


ItemInfluentFinal effluentRegional water quality standards
Extra-low stageHigh stageHigh stage
BOD 290 210 2 25 or bellow
COD(Mn) 120 120 8
Total nitrogen 41.5 37.7 14.1 30 or bellow
Total phosphorus 4.7 3.8 2.1 3.0 or bellow

Average values of 24-hour test conducted in FY2018

※ The higher values of BOD and COD indicate the higher levels of water contamination. BOD describes the amount of oxygen required by microorganisms to eat organic material in water, and COD describes the amount of oxygen required by oxidizer to decompose organic material in water. The quality levels of discharged water are specified in terms of BOD for rivers and COD for seas. Total nitrogen and total phosphorus are closely related to the generation of red tides.

Sewerage Components

The sewerage system is principally made up of 3 facilities.
Sewers, which collect and carry sewage.
Pumping stations, where sewage is pumped up so that the sewers do not get too deep.
Water reclamation centers, where sewage is treated to be clean water.
Inspections, cleaning, and repairs are done daily in order to make sure each of these facilities works properly.

Illustration:Sewerage System Components

The Role of Tokyo Sewerage

Improvement of Living Environment through Sewage Treatment

Sewage discharged from homes and factories is treated to ensure a comfortable living environment.

Illustration:Improvement of Living Environment through Sewage Treatment

Preventing Flooding through the Removal of Rainwater

The city is protected from flooding through the speedy drainage of stormwater which falls on land surface.

Illustration:Preventing Flooding through the Removal of Rainwater

Protecting the Global Environment

We treat sewage and release cleaned water, to carefully protect the water quality of rivers and the sea. We also recycle treated water and sludge, and utilize unused energy, as we work to build a recycling city.

Illustration:Protecting the Global Environment

Ground plan

Illustration:Ground plan

Features of Ochiai Water Reclamation Center

Contribution to urban water environment

The treated water is abundant in volume and steady in quality, and can be effectively used as the water for miscellaneous use in buildings. Ochiai Water Reclamation Center uses a sand filtration method for advanced water treatment. It sends reclaimed water to the Shinjuku Subcenter Water Recycle Center in Nishi- Shinjuku. The reclaimed water is effectively used as water flushing toilets in buildings in Nishi-Shinjuku and Nakano-Sakaue districts.

Illustration:POchiai Water Reclamation Center uses a sand filtration method for advanced water treatment

Restoration of streams in three rivers in the southern downtown area of Tokyo

The reclaimed water after advanced wastewater treatment in Ochiai Water Reclamation Center is fed into the three streams - Shibuya & Furu River, Meguro River and Nomi River, where water was stagnated and stream environment deteriorated in the past. This has contributed to the increase of water volume and recuperation of affluent water environment in the streams.

Photo:Recuperated Meguro River

Recuperated Meguro River with reclaimed water

RO Membrane Filtration Facility

In Ochiai Water Reclamation Center, the treated wastewater from the secondary sedimentation tank is all subjected to advanced treatment in the sand filtration tank. Further, 50 m3/day of advanced-treated water is subjected to Reverse Osmosis membrane filtration to supply hygienic and safe water to "Seseragi no Sato Public Garden" for children to play with the water.

Photo:RO Membrane Filtration Facility

Distance Monitoring and Control using Optical Fiber Communication Network

The operation control of the wastewater treatment facilities in Nakano Water Reclamation Center about 3 km away is carried out by using the optical fiber communication network installed inside sewer pipes.

Illustration:Distance Monitoring and Control using Optical Fiber Communication Network

Ochiai Summer Festa

We aim to be a water reclamation center loved by the local community. We hold this festival each year during summer vacation.


Ochiai Chuo Park

Ochiai Chuo Park is the first park in Japan which was built using the upper part of a water treatment plant in 1964. This park is equipped with baseball park, tennis courts, etc. A large number of people visit and enjoy the parks.

Photo:ochiai chuo park

Seseragi no SatoPublic Garden

Seseragi no Sato Public Garden has a chilidren's square with playground equipment, and  the  treated sewage through membrane filtration process flows in the waterway and the pond, providing the Garden with a comfortable waterside environment.

Photo:Seseragi no Sato Public Garden

Guide map


1-2-40 Kami-ochiai, Shinjuku-ku, Tokyo
Phone: 03-3366-6964 MAP


5-minute walk from Shimo-ochiai Station on Seibu Shinjuku Line.

Illustration of a guide map

Tokyo Sewerage Museum "Rainbow"

Tokyo Sewerage Museum Rainbow logo
There is a facility to enjoy the experience of learning about the sewerage system, its roles, and the importance of water environment.

  • Hours nine half o'clock to sixteen half o'clock
  • Entry Fee Free
  • Closed Mondays(open on holiday Mondays, closed the next day)and the New Year's season
  • Address 2-3-5 Ariake, Koto-ku Ariake Water Reclamation Center Management office(A-tower)5th floor
  • Telephone 03-5564-2458
  • Website Tokyo Sewerage Museum "Rainbow"

Tokyo Bureau of Sewerage

Tokyo Amesh

Tokyo Amesh is the system that shows rainfall in and around Tokyo in real time. The rainfall is measured by radars and ground rain gauges.

※ Tokyo Amesh is the registered trademark of the Tokyo Metropolitan Government.

Tokyo Amesh screen image

Virtual Sewer

Animation and video are used to allow people to experience the sewer system and wastewater treatment system in a fun way that would not be normally possible.

click Virtual Sewer

Beware of croocked dealer who pretend to be related to the Bureau of Sewerage!

The Bureau of Sewerage does not rely on businesses to repair or clean drainage facilities in housing.

Facility tours of Water Reclamation Centers

Facility tours of water reclamation centers are available except weekends, holidays, and the New Year's season.
Please contact us about reservations and details.


End Content

Start User Guide

End User Guide