What are the main causes leading to meter under-registration?

The use of private water storage or buffer tanks is a major contributor to meter under-registration. These challenges are further augmented in water networks such as Malta, where consumers use private water storage tanks to cope with irregular water supply. In contrast to a direct plumbing system, where water is fed directly from the main supply to the different outflow points (such as washing machine, flushing, water heater tank etc.), the use of private cold water storage tank creates an indirect plumbing system [1,2]. Cobacho et al [3], concludes that the bigger the surface area of the water tank, the lower would be the starting flow rate, hence, the higher the meter under-registration.

Water tanks on roofs tops are a major contributor to meter under-registration

Another major factor affecting meter performance (assuming appropriate meter sizing and no manufacturing faults) is meter age [5]. This result is reconfirmed by a local study [4], which found that domestic meter performance reduction (under/non-registration) was primarily attributed to ageing.


1.       A. Criminisi, C. Fontanazza, G. Freni, and G. La Loggia, "Evaluation of the apparent losses caused by water meter under-registration in intermittent water supply," Water Science and Technology, vol. 60, pp. 2373-2382, 2009.

2.       M. Fantozzi, A. Criminisi, C. Fontanazza, G. Freni, and A. Lambert, "Investigations into under-registration of customer meters in Palermo (Italy) and the effect of introducing Unmeasured Flow Reducers," Fantozzi% 20et% 20Al% 20Palermo% 20case% 20study% 20V4, vol. 20030309, 2009.

3.       R. Cobacho, F. Arregui, and E. Cabrera, "Private water storage tanks: evaluating their inefficiencies," Water Practice and Technology, vol. 3, p. wpt2008025, 2008.

4.       W. S. C. (WSC), "A Research project aimesat Improving the Water Metering Policy of the Water Services Corporation of Malta," Water Services Corporation (WSC), MaltaMarch 2017 2008.

5.       J. W. Male, R. R. Noss, and I. C. Moore, "Identifying and reducing losses in water distribution systems," Noyes Publications, Park Ridge New Jersey. 1985. 156, 1985.