Cost-benefit analysis - leakage reduction by rehabilitating old water pipelines: Case study of Oslo (Norway)

Water saving is not just the responsibility of the consumer. While demand-side management prescribes several good practices for water-consumers, the supplier also understands that leakage reduction on its part is a more effective mode of saving large quantities of water, by having to abstract, treat and supply less. It is not just water which is saved, but money spent on chemicals and energy expended on treatment and pumping. The economic aspect apart, this also means that there are possibilities of significant reductions of environmental impacts upstream in the chemicals production and energy generation processes. However, it is not an easy task to perform a comprehensive cost-benefit analysis, by taking into account all the direct and indirect costs and benefits. Benefits besides are not just multi-pronged but also distributed over time. In this paper, the author compares the direct costs incurred in rehabilitating old water pipelines in Oslo, with the direct benefits of leakage reduction which accrue therefrom, for the period 2011-2020. Avoided greenhouse gas emissions by virtue of savings in energy and chemicals are compared with the greenhouse gas emissions which occur due to the rehabilitation operations. It is seen that it often becomes difficult to justify rehabilitation economically, if the direct and indirect monetary benefits in addition those accruing from leakage reduction alone are not taken into consideration. Interestingly, the net savings in GHG emissions are significant, even over the 10-year study period.