Since the production of drinking water requires high costs, a large amount of water leakage affects the management of the water utilities.

Although the effective water ratio, the proportion of water used effectively without leaking, recorded less than 80% in the 1970s, the ratio at present is as high as 92%, through the water utilities’ efforts for the reduction of leakage.

Water leakage is not detected immediately in many cases because water pipes are laid underground.

It is therefore necessary to inspect pipes, based on a plan, for the detection of leakage and for the repair of leakage points, as well as to systematically make rehabilitation of aged pipes for leakage prevention.

The effects of the reduction of water leakage include not only reduction in the distributed amount, but also making new development of water sources unnecessary and contributing to cost reduction, which leads to improvement in management.

In addition, reduction in water leakage results in constant appropriate water pressure, which is essential for the supply of safe water.

■　National average of effective water ratio* is 92.7%. (Leakage is 7.3%).

■　The national goals of this ratio are set to be 98% for large utilities and 95% for small utilities.

■　Leakage Prevention in Tokyo

• System of leakage prevention measures

• Planned replacement of water pipes and improvement of materials for pipes

• Leak detection technology and early repairs

• Relationship between material of pipes and leakage rate

■　Water leakage improvement in other countries through Japanese technology.

• Effect of water leakage prevention measure

Advantages of pipe network management technologies such as network planning, water distribution control and water leakage minimization are reductions of energy consumption and leakage water caused by overloaded pumping pressure.

In addition, maintenance cost for electricity, water leakage measures and workforce can be also reduced.

As a result, water volume, pressure and quality are stabilized, contributing to safe and sustainable water supply operation.

■　Effect of Water Distribution Control System Application

• Increase of water volume and revenue

An application of the system increase the distribution water volume by decreasing water leakage.

• Reduction of Total Cost

An application of the system reduces total cost hence operational efficiency

Reduction of Running Cost

Distribution control matching demand reduces electricity charges.

On-line system reduces workforce for O&M.

Reduction of water leakage amount results in purification costs such as machinery engine and chemicals.

Reduction of Initial Cost

Proper network planning reduces pipe installation and pump equipment costs.

• Environmental Effect

○An extra energy consumption by overloaded pumping pressure is reduced.

○Water resource is reserved by reduction of leakage.

• Services

○Improvement of water supply service

High quality of service such as stable water pressure and quality is provided to customer in all service area.