Page 76 - Water Loss Control

58 Cha pte r F i v e

apparent losses. Depending on the local situation the final apparent loss intervention
program may consist only of one or a combination of several or all intervention meth-
ods which will serve to bring the apparent losses down to the economic optimum
volume.

5.5 Implementation Phase
Once the right intervention methods have been identified its time to implement them.
The implementation is either carried out in-house or contracted out depending on the
resources and the expertise of the water utility. In many cases, you can see a combina-
tion of in-house implementation and outsourcing.

5.6 Evaluate the Results
The evaluation phase at the end of the water loss control program is necessary to assess
the results achieved by the program. Basically a new water balance complemented by a
component analysis is undertaken and if necessary DMA measurements are carried out
and the results are compared to the results before start of the water loss control pro-
gram. If the intervention program took place on a DMA level then it is best to repeat the
DMA measurements after completion of the intervention.
If a program extends over several years then it is advised to measure the results at
least on an annual base to see if the water loss reduction efforts are moving into the
right direction.
It is important to bear in mind that once the goals are achieved it is necessary to
continue with the water loss control efforts in order to maintain the economic optimum
volume of water losses. This is necessary because water losses increase over time if no
control measures are taken. However, the efforts necessary to maintain the optimum
point will be less than the efforts that were necessary to get to the optimum point.

5.7 Examples of Water Loss Control Program Costs in North America
Cost effectiveness of demand-side water conservation programs is expressed in a cost
per unit of water saved. Since demand-side conservation is already widely applied in
North America, especially the western parts of the Unites States, there is a wide set of
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demand-side water conservation cost figures available. In a paper written by the
authors of this manual, the cost effectiveness of several water loss control programs
carried out in North America was assessed in order to compare the cost effectiveness of
water loss control programs with demand-side conservation programs.
This analysis showed that water loss control program costs do vary from utility to
utility. A general guideline is that water loss control programs are cheaper when the
volume of real losses is high. The lower the volume of real losses the more effort is
required to reduce them and therefore the overall cost for the program increases. See
Fig. 5.5 for a cost comparison of several water loss control programs. It is important to
note that all of these programs only reduced real losses with no intervention against
apparent losses. The cost shown includes all components of a water loss control pro-
gram starting at the point of assessment (water audit) and including all costs to inter-
vene against real losses including the cost to repair the leaks.