Speed and quality of repairs
Many Water Utilities have a good reputation for ensuring that 'reported' mains breaks are promptly repaired. However, many are not aware that such events usually account for only a small part (typically 15% or less) of the Current Annual Real Losses volume. The majority of Annual Real Losses volume consists of:
* background leakage (small hidden undetectable leaks at joints and fittings, running continuously), which are sensitive to pressure
* unreported leaks and breaks (see 'Active Leakage Control')
* known leaks which are not repaired for various reasons (often because of their low flow rates)
Consider the relative influence on known un-repaired small leaks on annual Real Losses volume. An un-repaired small leak running at 0.25 m3/hr for 1 year will lose around 2200 m3, or almost 5 times the volume of a reported mains break running at 20 m3/hour for 1 day (480 m3 lost). It is not only the flow rate of an individual leak that matters, but also the run-time. Speed and quality of repair of ALL detectable leaks – reported and unreported – is a prerequisite for effective leakage management.