This data indicates that the majority of the problem is in cast iron pipe installed in the 1950s. Perhaps this pipe was not manufactured well or was installed incorrectly or was installed in an area with harsh soil conditions.
This type of detailed analysis of operational data is only possible if data is collected on an individual asset basis or at least by asset class. The more detailed the data, the more advanced and detailed the analysis of costs can be.
This type of data collection will be easier if the data is stored electronically, but data on work orders can also be kept on paper. If the total time for repairs, parts used, and personnel and vehicles involved are kept on the work order, along with information regarding the specific asset on which the work was performed, an estimate can be made of the cost for each type of activity completed on the asset. The work orders can then be sorted by asset and associated asset costs can be tracked. The work orders can also be sorted by asset class (i.e., pipe, hydrants, wells) to determine costs by class. If the utility has very few assets and a limited number of work orders per year, this method can work well. The more assets and work orders you have, the more important it is to keep an electronic version of the data or at least examine the data more frequently to prevent data review from being overwhelming.
Beyond operation and maintenance costs, there are other types of cost data to collect on assets: initial capital cost, costs related to energy use, repair costs not included on work orders, and any other costs associated with the asset (environmental, social, legal). Initial capital cost can be obtained at the time the asset was installed, or the cost information may come from historical records. If no other data is available costs can be estimated. Costs related to energy can be obtained from estimates of energy use as discussed in Chapter 3. The Energy Inventory forms in Appendix A can also be used for this purpose.
Records of all of these costs should be kept on the individual assets in the most sophisticated system available to the utility, be it hard copy or electronic. The more asset-specific the cost data is, the easier it will be to make good decisions on the management of the assets.