Legislative Assembly for the ACT: 1998 Week 5 Hansard (27 August) . . Page.. 1576 ..
Period Number of Disruptions per Hundred
Note: Each individual blockage is assumed to disrupt sewerage services to an average of 1.8 properties. To obtain the blockage rate, the disruptions need to be divided by 1.8.
(4) Over the period from 1992 to 1998 the overall expenditure on preventative and reactive maintenance has increased by 50%. The balance of expenditure between preventative maintenance and reactive maintenance has been determined more by particular circumstances at a given time than by any other factor.
In this period a number of different maintenance techniques and equipment have been trialed. By and large more efficient, less hazardous, mechanically assisted methods have replaced the labour intensive manual methods of the past.
There seems to be little correlation between expenditure on preventative maintenance and the number of blockages experienced in the following year. Indeed the highest number of blockages in the period occurred in 1997/98, the year immediately following the largest expenditure on preventative maintenance.
A range of other external factors, in particular weather and ground conditions, seem to have the most significant influence on blockage rates. With this in mind ACTEW endeavours to apply its maintenance resources in the most efficient way to ensure minimal customer disruption.