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Water supply business outline

Final update date March 23, 2021

Outline of Yokohama City Water Supply Business in 2020

With Yokohama-shi water supply business summary, we gather every year to provide information about water supply business of Motoichi to visitor including introduction of water supply facility, financial situation and result of water examination.

We are pleased to inform you that the contents have been partially revised. The posted data has already been replaced, but if you have downloaded it by March 31, 2021, please download it again.
errata (PDF: 436KB)


The regulations about setting of Yokohama-shi water supply business and industrial water supply business


Chapter 1 Overview of Yokohama Water Supply

Summary of Chapter 1 Yokohama water supply (PDF: 2,694KB)
(1)History of Water Supply Business
(2)Water Supply System in Yokohama
(3)Yokohama City Water Supply Business Overview
(4)Changes in Water Supply Demand
(5)Water sources owned by Yokohama City
(6)Water sources owned by each company in joint development
(7)Water supply by year and month

Chapter 2 Introduction of Water Supply Facilities in Yokohama

Chapter 2 Introduction of water supply facilities in Yokohama City (PDF: 1,747KB)
(1)Transition of Water Supply Business
(2)Dam facilities
(3)Intake facility
(4)Water supply facilities
(5)Water purification facilities
(6)Distribution and distribution facilities
A: Water distribution block map
A: Water distribution blocks and reservoirs
C: Distribution pump
E: Water pipe extension by pipe type
(7)Waterworks Flow Sheet

Chapter 3 Major Business of Yokohama Water Supply

Chapter 3 Main business of Yokohama water supply (PDF: 1,766KB)
(1)Development of Yokohama Water Supply Long-Term Vision and Medium-Term Management Plan
(2)Basic facility development business
(3)Water pipe maintenance business
A: Summary Table
A: Pipeline network maintenance measures
C: Measures against aging pipes
E: Water pipe control measures for corrosive soil
O: Prevention of water leakage
(4)Sagami Reservoir Large-scale Construction Improvement Project

Chapter 4 Overview of Water Supply

Summary of Chapter 4 water supply finance (PDF: 1,065KB)
(1)Overview of Financial Statements
(2)Statement of Income
(3)Balance Sheets
(4)Personnel and staff
(5)Financial Analysis Ratio
(6)Issuance of bonds
A: Overview of Issues
A: Unpaid balance of corporate bonds (end of each fiscal year)
C: Unpaid balance by interest rate
(7)Results of National Treasury Subsidy and Grants

Chapter 5 Water Charges in Yokohama

Chapter 5 Yokohama City Water Charges (PDF: 1,183KB)
(1)April 2001 Rate Revision
A: Comparison before and after the revision of the water rate system
A: Overview of Rate Revisions
(2)Medium-term management plan (Reiwa 2 to Reiwa 5) Fiscal balance plan and performance comparison
(3)Water subscription unit price
(4)Number of water supply units by use and year, amount of water received, toll revenue
(5)Number of water supply units by use and stage, amount of water received, toll revenue
(6)Amount of water received by use or excess or excess

Chapter 6: Creating Water Resistant to Disasters

Chapter 6 Making Water Resistant to Disasters (PDF: 2,121KB)
(1)Emergency water supply plan
(2)Breakdown of Disaster Underground Water Tanks by Administrative District
(3)Disaster Water Station (Disaster Underground Water Tank) and Reservoir
(4)Emergency hydrant installation list
(5)disaster drill To Prepare Disasters
A: disaster drill in the Community (Emergency Water Supply Training)
A: Joint disaster drill
(6)Efforts to Stock up on Drinking Water
A: Sales of Yokohama Water Cans
A: Efforts to promote stockpiling
(7)Maintenance of water supply facilities for disasters
(8)Efforts to secure repair materials in the event of a disaster
(9)Development of emergency power generation facilities
(10)Efforts to secure fuel
(11)Measurement of radioactive materials
(12)Support for Great East Japan Earthquake affected areas

Chapter 7 To deliver safe and high quality water

Chapter 7 (1) to (3) to deliver safe and high quality water (PDF: 1,677KB)
(1)Water quality improvement measures
A: Environmental Improvement Projects and Maintenance Projects for Lake Sagami and Lake Tsukui
A: Installation of Aoko fence at Sagamiko intake
C: Water use burden related to the Sagami River basin sewerage around Lake Sagami and Lake Tsukui
E: Subsidy for Doshimura Wastewater Treatment Business
O: Improvement of water quality by injecting activated carbon
Ca: Nishitani Water Purification Plant Water Treatment Experiment
K: Cryptosporidium countermeasures (turbidity control measures)
(2)Water quality standards and water quality items
(3)Plan and results of water quality inspection
A: Water quality inspection point
A: City water quality inspection point
C: Aging of water quality
E: Water Quality Overview
Chapter 7 To deliver safe and high quality water (4) to (6) (PDF: 1,674KB)
(4)Management status of water supply equipment and water tank water supply
A: Improvement of management level of water tank water supply
A: Management classification by receiving tank capacity (Yokohama)
C: Inspection organization for water tank
E: Water tank water supply patrol inspection
(5)Aging water pipe improvement promotion project in the road
(6)Promotion of direct water supply

Chapter 8 Industrial Water Supply Business

About Chapter 8 industrial water supply business (PDF: 1,025KB)
(1)History of Industrial Water Supply Business
(2)Business Overview
A: Retained water sources (water rights)
A: Construction and Construction Fund Overview
C: Water supply capacity
E: Water supply area and distribution pipe extension
O: Water quality standards for industrial water
Ca: Number of staff
(3)Financial status
A: Overview of Financial Statements
A: Statement of Income
C: Balance Sheets
(4)Revision of Industrial Water Charges
A: Outline of Industrial Water Rate Revision
A: Industrial Water Charges
C: Medium-term management plan (Reiwa 2 to Reiwa 5) Fiscal balance plan and performance comparison

Chapter 9: Kanagawa Prefecture Wide Area Water Supply Corporation

About Chapter 9 Kanagawa wide area water supply corporation (PDF: 1,074KB)
(1)Outline of Founding Business
(2)Outline of Sagami River Water System Construction Project (Phase 1)
(3)Water supply breakdown
(4)Water rate breakdown
(5)Breakdown of Water Supply Fees from Enterprises
(6)Breakdown of water received by corporate associations
(7)Financial Statements by Element and Budget


Reference (PDF: 947KB)
(1)Water Works Bureau Organization List
(2)Water Works Bureau organization and division of affairs

back cover

Open Data

2020 Yokohama City Water Supply Business Overview Open Data

Information on population served, water supply, toll revenue, etc.

Listed the maximum water supply, load, average water supply, etc.

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For inquiries about water supply, please contact Water Works Bureau Customer Service Center.

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Telephone: 045-847-6262 Fax: 045-848-4281
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Corporate Planning Division, Water Works Bureau Business Planning Division

Telephone: 045-671-3127

Telephone: 045-671-3127

Fax: 045-212-1157

Email address: [email protected]

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