A diurnal water demand pattern was considered for the two networks, as shown in Figure 4. The daily maximum hourly demand had a peaking factor of 1.5 from 6 to 7 pm while the minimum hourly demand had a peaking factor of 0.6 at 2 am. A typical electricity tariff structure (Table 2) with three discrete periods was applied to both networks to calculate the pump energy cost. The electricity unit cost was 3.25 times higher during the peak hours than during the lowest tariff hours. Avoiding pumping during peak hours (6 am–3 pm) reduced energy costs; however, this was difficult to achieve because of the high water demand during this period. For the calculation of the POC, the optimal diurnal pump operation was assumed to be repeated over the planning period (20 years).