Some 16 percent of water production was used but not billed last year because of faulty metering, according to WSC estimates. Another 18 percent were lost in leakages.
The figures were disclosed by the Auditor-General in a report to Parliament in which he urged the Water Services Corporation to intensify its efforts to reduce the level of water losses to one which is closer to what is considered as unavoidable.
He pointed out, however, that on the basis of available statistics, the corporation's initiatives to detect, monitor and record water losses have alrerady led to significant reductions in such losses.
The observations were made after a performance audit of how the WSC carried out its responsibilities to minimise water losses.
The auditor explained that due to a number of factors, a discrepancy between the system input volume and the amount of metered water materialised. These losses were categorized as real and apparent losses.
Real losses referred to physical water losses from the pressurized distribution system, up to the point of customer metering.
The WSC estimated that, in 2007, real losses amounted to over 18 percent (5.6 million cubic metres) of the system input volume.
On the other hand, apparent losses referred to the water that was consumed but was not properly measured, accounted or paid for. In 2007, the WSC estimated that apparent losses totalled around 23 percent (7.56 million cubic metres) of the system input volume.
"Through various initiatives over the years, the WSC has significantly reduced real losses mainly as a result of significant capital investment in the water distribution system," the auditor said.
"The corporation gauges the effectiveness of its management of real losses through an internationally recommended benchmark - the Infrastructure Leakage Index (ILI). An ILI close to 1.0 indicates that all aspects of a successful leakage management policy are being implemented. Generally, it is considered economically viable for the ILI of most systems to be between 1.5 and 2.5. The corporation is striving to attain an ILI of 2.0 within the hydrologically encapsulated zones by the end of this year. For zones in Malta, the ILI decreased from 5.0 in 2004 to 2.97 in 2008. The ILI for zones in Gozo has been stable at around 1.5 for the last five years."
The auditor said the WSC was increasingly shifting its focus to also deal with apparent losses. It was yet to determine the amount of such losses which were unavoidable.
It was pointed out that customer meter inaccuracies also contributed towards apparent losses, generally through the under registration of consumption.
"All meters of the mechanical type suffer from a reduction in performance over time. In 2008, a WSC internal study concluded that the corporation is not billing nearly 16 per cent of water consumption due to meter inaccuracies. Such a problem is mainly caused by meters which are aged 10 years and over, of which there are over 51 percent of the total meters installed. It has been announced that the corporation is in the process of making substantial investment in the purchase of modern meters which will render the meter reading process more efficient and reliable."
UNAUTHORISED CONSUMPTION
The auditor said apparent losses also resulted through unauthorised consumption.
"Although the issue of adequately addressing water theft seems not to have been given the very high priority it deserves, recently the WSC started to adopt a stricter stance towards water theft. Legal Notice 331 / 2008 states that whenever it is found that any tampering with or damage to the water communication has been made, the Corporation shall request the consumer to pay damages in an amount of not less than €1,500."
The auditor proposed the adoption of an economic leak intervention model to assist in the prioritisation of infrastructural works, maintenance and repairs, as well as to tackle water theft through a more proactive and aggressive approach.