Miya is a leading global provider of comprehensive solutions for urban water efficiency. Miya's solution is based on best-practice methodology developed by the International Water Association (IWA).

Overview

In 1996, the IWA formed the Water Loss Task Force (WLTF). The Task Force was mandated with the task of standardizing the terminology and procedures used to carry out a water balance audit, as well as to develop clear and meaningful performance indicators to assess both the operational and financial performance of a water utility with respect to water loss.

The outputs of the WLTF's activities involved:

• A standard water balance using international terminology
• Performance indicators to assess the functioning of the water utility
• Strategies for water loss reduction

Many international standards have been developed using the IWA approach to water loss management. In addition, the strategies advocated by the WLTF became the best "practical approach" to reducing water losses in many countries.

A Standard Water Balance

The major challenge facing water utilities and municipalities is how to deal with high levels of Non-Revenue Water (NRW). NRW is the gap between the amount of water put into the distribution system and the amount of water for which customers are actually billed. High levels of NRW reflect huge volumes of water being lost through leaks (real/physical losses), water not being invoiced or not being accurately measured (apparent/ commercial losses) or both.

A water balance audit details how much of each type of loss is occurring and how much it is costing the water utility. The key concept behind this approach is that water should not be "unaccounted-for". In conducting a water balance audit, a quantity is determined for the major components of water consumption and water loss, and a price is placed on each component in order to assess its financial impact on the water utility. A detailed and accurate water balance forms the basis for an effective NRW management strategy.

The 4-Component Approach

The 4-Component diagram, shown below, is widely used to explain the types of activities that are effective in managing real and apparent losses.

Managing Real Losses

Real losses cannot be completely eliminated. The lowest technically achievable annual volume of real losses - for well-maintained and well-managed systems - is known as Unavoidable Annual Real Losses (UARL). Based on an appropriate combination of all four activities involved in leakage management (shown as arrows in the diagram), real losses can be kept to a minimum. In modern systems three of these methods have proved themselves to be more cost-effective in the short term than pipeline and asset management:

• Active leakage control
• Improvement of speed and quality of repairs
• Optimization of the pressure management in the system

In systems which were built from poor quality materials or which suffer from substandard installation practices, it is often necessary to consider medium and long term solutions which include pipeline and asset management.

Managing Apparent Losses

The following four components make up the IWA management strategy for apparent loss:

• Customer meter inaccuracies
• Unauthorized consumption, illegal connections, theft and fraud
• Data analysis errors, between archived data and data used for billing
• Data collection and transfer errors between meter and the billing system

Commercial losses should be no more than a few percentiles of authorized consumption. Combating commercial losses does not require substantial financial resources, but rather demands a firm commitment on the part of the utility management, political will, community support and incentives.

Dealing with all four components in a coordinated fashion will result in reducing the annual quantity of apparent losses to an economic level.

In some cases it is recommended that commercial loss reduction be the first step in an NRW reduction strategy, since it requires a relatively low investment and can result in immediate payback.