How are we tracking?
Indicator: Number of properties that experience unplanned water interruptions
Water main breaks can cause significant disruption to our customers. They often result from moisture changes in the soil causing movement in the pipes, accidental damage by third parties and loss of strength from long-term corrosion. We have programs to minimise unplanned water interruptions and to respond quickly when they do occur.
Our Operating Licence 2010–15 requires that:
no more than 40,000 properties in a year experience an unplanned water interruption of more than five hours
no more than 14,000 properties in a year experience three or more unplanned water interruptions of more than one hour.
In 2011–12, we met these conditions. There were 28,386 properties that experienced unplanned water interruption for longer than five hours, and 4,171 properties that experienced three or more unplanned water interruptions of more than one hour.
The number of properties affected by unplanned water interruptions is closely linked to the number of faults or instances of broken mains that require the water supply to be isolated so we can fix them.
Indicator: Response times for water main breaks
We respond to water main breaks and leaks reported by customers based on priority. The priority system ranges from 1 (least urgent) to 6 (most urgent). Our Operating Licence 2010–15 sets targets for the percentage of jobs we must finish within set response times for Priority 4, 5 and 6 breaks and leaks.
In 2011–12, we met all response time targets. We measure the response time from when we receive notification of a break or leak to the time water loss stops.
To reduce the impact of water main breaks and leaks, we:
assign maintenance crews to the areas of highest workload
assign staff from lower priority work to maintenance crews and use contractors for low-risk repairs.
Table 12 – Response times for water main breaks 2011–12
Indicator: Low water pressure
Water pressure is the force at which water moves from our mains into customers’ pipes. Our Operating Licence 2010–15 specifies that no more than 6,000 properties a year should experience water pressure (at the connection point to our main) below a set level. Water pressure is considered low if less than 15 metres pressure head (the height a spurt from a main would shoot into the air) for a continuous period of 15 minutes or more.
In 2011–12, 572 properties experienced low water pressure, compared with 832 properties last year. Most of these were due to a customer drawing a large amount of water from the Macarthur system, which affected pressure for 376 properties. We spoke with the customer to try to prevent this from happening again and are investigating ways to maintain pressure within the system.
The number of properties affected by low water pressure has been consistently well below the Operating Licence standard of 6,000 properties since 2006–07.
Table 13 – Number of properties that experienced low water pressure 2007–08 to 2011–12