Leakage Management in the United Kingdom

This section refers to England and Wales when talking about the United Kingdom, since those are the two regions with the most structured leakage management regulations in the United Kingdom.

An interesting contrast can be drawn between the proactive system addressing water loss in England and Wales and the current conditions in the United States. A number of factors contributed to the establishment of England's progressive demand and leakage management structure in the 1990s. The reorganization, privatization, and regulation of the small number of large water companies in 1989 created an important change in the business model used for water supply. With revenue growth potential limited due to government regulation of customer rates or tariffs, leakage reduction was one of many efficiency improvements targeted by the companies to cut costs and improve their bottom line. The National Leakage Initiative of the early 1990s was a major research project underwritten by the water companies to determine the best methods to employ to reduce leakage. The severe drought of the mid-1990s prompted mandatory targets for leakage reduction from the government's economic regulator,

Office of Water Services (Ofwat); which most companies have achieved due to their ability to quickly implement the recommendations of their leakage reduction research. Enormous efforts to control water losses were undertaken in the United Kingdom since the early 1990s, with water loss reduction being a major operational task for water utilities. Today, water companies in the United Kingdom have a detailed understanding of their components of water losses and the economic optimum of their losses. The water companies now operate "transparently" in calculating and publicizing data on their water loss volumes. Most companies claim that they have reached, or will reach soon, their economic optimum level of leakage. Total leakage in England and Wales was reduced from 1350 mgd (5112 ML/d) in 1994-95 to 856 mgd (3243 ML/d) in 2000-01. This represents a reduction of 37% in leakage or a volume of 528 mgd (2000 ML/d), enough water to supply more than 12 million people.

A rise in leakage volume during the 2001-02 year (see Fig. 4.4) was caused by increasing leakage volumes at Thames Water, which have continued to increase against the general downward trend seen from all other England and Wales water companies. In 2002-03, Severn Trent Water showed a rise in its leakage volumes as well. Both companies are under strict scrutiny by Ofwat to ensure that they improve their performance according to their set targets. Thames Water and Severn Trent Water aside, leakage volumes for all of the remaining water companies have continued to fall further.

Severe drought in the United Kingdom in the mid-1990s prompted mandatory leakage reduction—a scenario that could materialize in the United States given its many drought-stricken regions.

Total Leakage England and Wales from 1994 95 to 2005 06

6000

2000

1000

5112

3367

4980

□ Total leakage England and Wales

□ Total leakage without Thames and Severn Trent

3238

4528

2968

3989

2684

3551

2437

3306 3243

3414

3605 3649 3608 3604

2305

2215

2207

2148

2191

2191

2169

94/95 95/96 96/97 97/98 98/99 99/00 00/01 01/02 02/03 03/04 04/05 05/06

Figure 4.4 Leakage reduction in England and Wales between 1994-95 and 2005-06. (Source: Ofwat, compiled from annual leakage reports—in public domain.)

Regulations for Leakage Management

After the privatization of the water supply industry in England and Wales in 1989, 10 large regional water supply and sewerage companies were formed, which, together with 16 statutory water supply only companies, cover the entire water supply of England and Wales regulated by the Water Act of 1991. U.K. governance features two primary regulatory bodies for the water industry, Ofwat and the Environment Agency (EA). Ofwat serves as the economic regulator and the EA as the environmental regulator. Each water company is required by Ofwat to produce a detailed annual report on the volume of water supplied, consumed, and lost in each component part of the network, using a standardized water balance (similar to the standard IWA water balance). The water balance results have to be cross checked via minimum hour flow analysis of data from DMA, which are discrete zones established to distinguish leakage events from customer consumption.

The results of these reports are used by Ofwat to assess the performance of each utility, to set performance targets and for intercompany comparisons. The mandatory leakage targets set by Ofwat for each water company (in ML/d) must be met by the company in order to avoid sanctions by Ofwat.

Overall, the assessment, reporting and management of water losses are highly regulated in England and Wales. This is paired with clear definitions, measures, and standards for assessing and evaluating water losses. The two regulatory agencies monitor the performance of all water companies closely and set performance and efficiency targets driven by an economic optimum volume of leakage established for each water company.

Leakage Management Practices

Developments of the past 20 years have resulted in a detailed understanding of the interaction between the four fundamental leakage management practices:

• Infrastructure management

• Pressure management

• Active leakage control

• Speed and quality of repair

The understanding and accurate assessment of the economic optimum volume of leakage is another major development and forms an integral part of a utility's water loss management strategy. Coherent leakage management strategies and oversight by regulatory bodies rely upon a uniform way of assessing water losses and setting economically and environmentally justified loss reduction targets. The main pillars of the highly successful leakage management practices used in England and Wales are

• Improved business focus: Departments and teams were created with the sole purpose of managing and reducing water losses to an optimum volume.

• Improved data quality: It was realized that the quality of data used for the water audits and establishment of targets was fundamental for a successful leakage management strategy.

• Routine calculation of water balances and performance indicators: In order to define and refine intervention targets and measures, standardized water balances and performance indicators are calculated routinely. These calculations are supported by DMA minimum hour flow analysis.

• Network zoning and DMA establishment: It was acknowledged that one of the most efficient ways to reduce the volume of real losses is by reducing the runtime of leaks. DMAs and the related minimum hour flow measurements allow the leakage manager to deploy the leakage reduction recourses to those areas where leakage levels have reached a volume that justifies intervention.

• Pressure management: It is now a well-known fact that pressure management is the most effective and efficient way of reducing leakage. The general benefits of pressure management are threefold: reduction of background leakage, reduction of break rates on mains, and service connections and reduction of flow rate from any leak.

• Reduced response time to repair leaks: Once it was recognized that the run time of a leak is major factor contributing to the overall real loss volume; steps were taken to ensure that the average repair times were drastically reduced.

• Customer side leakage: After it was understood that a significant portion of the leakage volumes can occur on customers side of the service pipe, effective management of this leakage component was included in the over all leakage reduction strategy.

• Improved leak detection efforts: A leakage reduction program is only as good as its field personnel finding the leaks. Therefore, comprehensive training programs were developed in order to increase the skill level of the leak detection personnel.

• Asset management: It was realized that leakage management is an integral part of asset management. Infrastructure replacement is the most comprehensive improvement to an asset, but this action is also the most expensive step of the four management practices. A concentrated effort was launched to develop sophisticated asset management techniques to plan infrastructure investments and replacements on a strategic basis.

These leakage management practices are discussed in further detail in Chaps. 10 to 14.

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