Economy and population is growing at a healthy pace in the Maltese islands and it is unprecedented that the environmental, economic and social costs associated with water production, equally follow an increasing trend. Water utility companies seek more accurate and precise ways of quantifying water losses within their networks, and aim to achieve better comprehension with subsequent correct measurement with the understanding that what can be properly quantified can be managed and controlled. Understanding elements of Non-Revenue Water (NRW) is crucial for good governance of any water-supply. NRW refers to water which is not being billed and hence, no payment is received by the water entity for its consumption. The obvious consequence of NRW is the adverse financial consequences for the utility company, whereby the loss of funds results in poor reinvestments necessary to upgrade and keep a water network in a healthy state. Furthermore, significant NRW can lead to excessive water demands combined with requirements for more resources and operational expenses to supply additional water

Non-Revenue Water is composed of Apparent Losses (AL) and Real Losses (RL), which to date have proven relatively challenging to adequately quantify and were the centre of many a discussion. Vermesch et al [1], defines AL as the volume of water consumption that reach consumers, but is not billed. Moreover, RL refer to the actual physical water leakages in the water distribution network and storage facilities. Hence, in reducing RL the utility company can lower the overall cost of production, whilst in reducing AL, the utility company can increase the billing income without increasing the tariffs. Whilst utility companies strongly focus on reducing RL, AL are often overlooked due to the complexities of the topic, and this can lead to a scenario where the apparent loss index (ALI) is  higher in Real Losses Index usually referred to the infrastructure leakage index (ILI).

A. Criminisi et al [2], explains that in most cases AL are often attributed to meter under-registration/meter inaccuracies. Whereas with any measuring instrument, water meters unavoidably have a margin of error in registering a  true value, which becomes more significant with meter age. The measuring error of a meter at a given flow rate is defined as the difference between the volume registered by the water meter and the actual volume consumed.

Currently, there is a lacuna of knowledge in understanding the relationship among various factors affecting meter under-registration in Malta. Within this context, a large-scale testing of water meters is being planned through a joint collaboration between the Malta College of Arts, Science and Technology (MCAST) and the Water Services Corporation (WSC). This collaborative research aims to widen the knowledge on the specific meter under-registration portion of AL on the whole island meter population. The outcome results of meter under-registration will provide tangible results to WSC, namely:

  • Compare the performance of mechanical meters of different manufacturers;
  • Understand the degradation of mechanical meters currently in use by WSC as they age;
  • Understand the  degradation of mechanical meters currently in use at WSC  installed in different water-quality zones;
  • Understand how the performance of mechanical meters changes according to the number of people living in the household.
Figure 1: Research Gap – Factors affecting meter under-registration

Figure 1 presents the various factors that affect the performance of meter under-registration. By merging the factors, this research work aims to provide a holistic picture on meter under- oregistration. Furthermore, the study aims to reach the following objectives:

  • Produce a meter degradation profile for each meter manufacturer utilised locally;
  • Identify the best time at which a water meter should be replaced according to the manufacturer, water-quality zone, and number of people living in the household;
  • Establish whether other meter technologies or specifications should be included in future tenders when procuring.

The testing will be done using the ‘PT20 Test Rig for Water Meters’, specially designed and assembled by SENSUS® (SENSUS 2016), for installation and operation at the Institute of Applied Sciences (IAS) – MCAST. The main function of a water meter test bench/rig, as the name suggests, is to quantify accurately the operational efficiency for water meters (under certain variable conditions – temperature, pressure, water density, etc.), and thus determine whether water meters conform to specifications and standards and/or for research and development purposes (such as meter inaccuracy profiling).

The main basic concept behind the test bench is to pass a known volume/weight of water at a certain flow rate under certain parameters (temperature, pressure, etc.) through the water meter in order to differentiate quantitatively between the meter registered value and the actual measured (true) value of delivered water mass/volume. This test bench, seen in Figure 2, was tailor-made to simulate very low flows, like those induced by the predominant indirect plumbing systems (using roof tanks) found in the Maltese Islands, with the aim of accurately quantifying meter inaccuracies as a result.

Figure 2: PT20 Test rig for water meters

The proposed research study aims to evaluate water-meter under-registration, specifically the effect of ageing on the meter, controlled at different flow-rates. This joint collaboration can offer wide ranging benefits. Primarily it aims to actively contribute to research on the under registration portion  of apparent losses in Malta whilst also serving as a tool to assist  WSC in future savings in lost revenue.

Ing. Christian Camilleri* obtained the B. Eng. (Hons) degree in mechanical engineering from the University of Malta where he finalized his undergraduate study with a successful thesis focused on additive manufacturing of biomedical parts. Subsequently, he joined the Department of Industrial and Manufacturing Engineering (DIME) at the University of Malta, as a Research Assistant where he furthered his studies in micro manufacturing at postgraduate level. Since 2016, he works as Project & Research Engineer within the Research & Innovation Office. As academic, he is involved in research and lecturing of subjects primarily related to Apparent Losses, Biotechnology and Injection moulding. Christian is also an Editorial Board member of the MCAST Journal of Applied Research & Practice.

* Corresponding Author –

Inġ. Luke Pace graduated with Honours in Mechanical Engineering with Industrial and Materials Engineering from the University of Malta in 2013 and then read for a Master of Science in Engineering (Mechanical) following research at the Department of Industrial and Manufacturing Engineering at the University of Malta along with research at the Institut de Chimie de Clermont-Ferrand of the Ecole Nationale Supérieure de Chimie de Clermont-Ferrand (ENSCCF). As a professional within the Metering Section, Luke is responsible for the implementation of the smart metering project within the Maltese Islands. This includes the deployment and maintenance of RF modules on consumer water meters, be it residential or industrial, along with the monitoring and upkeep of the VHF receiver layer and any ancillary equipment and the timely issuing of consumer bills. Additionally, he is also responsible for the metering of agricultural boreholes within the islands, in order to measure and monitor the uptake of water from ground water sources.


Dr Alex Rizzo’s main areas of expertise are in vocational education & training (VET), alternative technologies, grounded theory research, and integrated water resources management. Alex presently acts as a Deputy Principal for the Applied Research Department at the Malta College of Arts, Science and Technology (MCAST). Prior to this he had set up and managed the MCAST Institute of Applied Sciences. Alex’s previous engagements included Deputy Chairman at the Malta Water Services Corporation (WSC), and various engineering and management roles within the water utilities sector where he has worked for over 15 years, taking on various engineering and management roles. Alex is a Fellow and Chartered Member of the Institution of Engineering & Technology, the Chartered Management Institute and the Chartered Institution for Water and Environmental Management.



  1. Vermersch, M., Carteado, F., Rizzo, A., Johnson, E., Arregui, F. and Lambert, A., 2016. Guidance notes on apparent losses and water loss reduction planning. Unpublished report.
  2. Criminisi, A., Fontanazza, C.M., Freni, G. and Loggia, G.L., 2009. Evaluation of the apparent losses caused by water meter under-registration in intermittent water supply. Water Science and Technology60(9), pp.2373-2382.

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