5.0 Overview The water balance and all its components as developed by IWA are explained in detail. The practical determination/calculation of all the components is shown step by step. The WB-easyCalc software is presented for calculating the water balance. The software is available at the lesson and can be tested. An important point is the estimation of the accuracy of all data input to the water balance. WHAT WILL YOU LEARN?

A FREE water chemistry tool useful for achieving the desired mash pH and preferred water characteristics when brewing beer. The IWA water balance and developing a NRW reduction strategy 17 May 2012. WB -EasyCalc The Free Water Balance Software Version 4.04 (May 13, 2011).

The water balance and its components are understood. Information Strategy In Practice Elizabeth Orna Pdf. The different components of the water balance can be determined and their accuracy estimated. A specific software is known and can be used. 5.1 IWA International Standard Water Balance The first step in NRW management is to understand what happens to the water once it enters the network, using the correct Performance Indicators. The concept is based on the work of the IWA Water Loss Task Force (WLTF).

Drawing on best practice from many countries, the IWA WLTF produced an international ‘best practice’ standard approach for water balance calculations with definitions of all terms involved. The figure below shows the IWA standard international water balance and terminology. IWA standard international water balance and terminology] The definitions of the principal components of the IWA water balance are as follows: • System input volume is the annual volume input to that part of the water supply system • Authorised Consumption is the annual volume of metered and non-metered water taken by registered customers, the water supplier, and others who are implicitly or explicitly authorised to do so (e.g. Water used in government offices or fire hydrants). It includes exported water and the leaks and overflows after the point of customer metering. • Non-Revenue Water (NRW) is the difference between system input volume and billed authorised consumption. NRW consists of unbilled authorised consumption (usually a minor component of the water balance) and water Losses.

• Water Losses is the difference between System Input Volume and Authorised Consumption, and consists of apparent (commercial) losses and real (physical) losses. • Commercial Losses sometimes referred to as ‘apparent losses’, consist of unauthorised consumption and all types of metering inaccuracies • Physical Losses sometimes referred to as ‘real losses’, are the annual volumes lost through all types of leaks, bursts and overflows on mains, service reservoirs and service connections, up to the point of customer metering. 5.2 Calculating the Components The components of the water balance should always be calculated as volumes before any attempt is made to calculate performance indicators. The separation of non-revenue water into components • Unbilled authorised consumption • Commercial (apparent) losses and • Physical (real) losses should always be attempted. Sometimes even the most basic information, such as system input volume, average pressure, supply time, length of mains, and the number of service connections, is not initially available. The process of calculating each of the water balance components and performance indicators will reveal such deficiencies.