3.1. Nontrevenue water estimates for Cameroon
The overall national volume of NRW or water loss is estimated at 232,018 cubic meters per day or 84.7 million cubic meters per year (Table 2). This volume of NRW is unequally distributed according to the area of residence. Indeed, the volume of NRW in urban and peri-urban areas is 225,856 cubic meters per day (82.4 million cubic meters per year), while in rural areas, the volume of NRW is 6,162 cubic meters per day (2.2 million cubic meters per year). Assuming a value of 326 CFA francs (USD 0.54) per cubic meter in urban areas and 750 CFA francs (USD 1.25) per cubic meter in rural areas, the cost or value of the water lost per year was 28.6 billion CFA francs (USD 47.6 million). By cutting Cameroon’s NRW to half its present level, approximately 1.2 million people could be supplied, including 1.1 million in urban areas and 100,000 in rural areas (assuming a per capita consumption of 100 litres per day in urban areas and 30 litres per day in rural areas).
Table 2
NRW estimates for Cameroun
Areas | Volume of NRW | Average level of NRW (l/c/d) | Cost value of NRW |
m3/day | Million m3/year | Billion CFA francs/year | Million USD/year) |
Urban | 225,856 | 82.4 | 47.1 | 26.9 | 44.8 |
Rural | 6,162 | 2.2 | 6.9 | 1.7 | 2.8 |
National | 232,018 | 84.7 | | 28.6 | 47.6 |
A comparison of the model results to actual country data from the Camwater database reveals a very good correlation in urban areas. The average from the new NRW model is 82.4 million m3/year, compared with the 90.3 million m3/year estimated by Camwater (2023), which is a difference of only 8.7% (Table 3).
Table 3
Comparison of the NRW model results with data from Camwater
Areas | Volume of NRW (Million m3/year) | Difference | Percentage of difference |
Estimations/Model | Camwater (2023) |
Urban | 82.4 | 90.3 | 7.9 | 8.7 |
Rural | 2.2 | * | - | - |
National | 84.7 | * | - | - |
*Data not available |
The analysis of NRW volumes by region (Table 4) shows that approximately 50% of the NRW volume comes from the Yaoundé and Douala drinking water distribution networks. This is because approximately 40% of the population using drinking water distribution networks lives in Yaoundé and Douala. Table 4 also shows that, in addition to Yaoundé and Douala, the region with the highest NRW volume is the Far North region (17,431 m3/day), the Western region (17,002 m3/day), the North‒West region (15,043 m3/day), the South‒West region (12,969 m3/day), the North region (11,330 m3/day), the littoral region except Douala (8,877 m3/day), the central region except Yaoundé (8,279 m3/day), the Adamawa region (8,025 m3/day), the East region (6,611 m3/day), and the South region (5,337 m3/day).
The high level of NRW can be explained by the strategy adopted by the water supply company to manage water losses. In fact, water utilities (Camwater) practice passive leakage control, meaning that failures and related leakages are removed when they appear on the surface and are reported or when they cause limitations in the water supply. This is clearly not enough since 90% of the leaks are usually not visible on the surface (Frauendorfer & Liemberger 2010). This means that it takes far too long—often many years—before the Camwater is even aware that there is a leak. Since the amount of water lost from a pipe burst is primarily dependent on the duration of awareness, for example, a spectacular burst on a water main running at 20 m3/h (480 m3/day) would often be repaired on the same day. The total volume of water lost would be 480 m3. In comparison, a small leak on a service connection of only 20 m3/day may occur all year if there is no active leakage control. In this case, the volume of water lost would be 7,300 m3 (Frauendorfer & Liemberger 2010).
Table 4
NRW cost value estimates for the Cameroun region
Region | Volume of NRW | Cost value of NRW |
m3/day | Million m3/year | Billion CFA francs/year | Million USD/year |
Yaoundé | 59,762 | 21.8 | 7.1 | 11.9 |
Douala | 61,353 | 22.4 | 7.3 | 12.2 |
Adamawa | 8,025 | 2.9 | 1.0 | 1.7 |
Centre (except Yaoundé) | 8,279 | 3.0 | 1.1 | 1.8 |
East | 6,611 | 2.4 | 0.8 | 1.4 |
Far north | 17,431 | 6.4 | 2.3 | 3.9 |
Littoral (except Douala) | 8,877 | 3.2 | 1.1 | 1.8 |
North | 11,330 | 4.1 | 1.5 | 2.5 |
North‒west | 15,043 | 5.5 | 1.9 | 3.2 |
West | 17,002 | 6.2 | 2.1 | 3.5 |
South | 5,337 | 1.9 | 0.7 | 1.1 |
South‒west | 12,969 | 4.7 | 1.6 | 2.7 |
National | 232,018 | 84.7 | 28.6 | 47.6 |
3.2. Challenges of reducing nonrevenue water
A high level of nonrevenue water in Cameroon is influenced by several factors, such as rapid urbanization, outdated infrastructure, and a high level of poor operation and maintenance, including ineffective record keeping systems, water meter inaccuracies, and inadequate technical skills and technology. This has been highlighted by several authors (Farley et al. 2008; Frauendorfer & Liemberger 2010; AfWA & USAID 2015) and should be addressed to reduce nonrevenue water.
Rapid urbanization influences the scope of managing NRW. Indeed, the growth of cities is not controlled. In the city of Douala, for example, between 1980 and 2000, the city's population tripled, rising from one to three million inhabitants. During the same period, the spatial extent followed the same trend, increasing from 65 km2 to 185 km2 (CUD 2004; Hatcheu 2006). It is difficult to develop a master plan for hydraulics in such a context and to proceed today to find a balance between demand and supply. The third general census of population and housing since independence in 1960 took place in November 2005, more than 18 years after the second was carried out in April 1987. In such a context, it was difficult to establish a plan. It is worth mentioning that efforts are underway with the help of donors. However, they arrive late and remain insufficient insofar as the problem is structural.
The majority of Cameroon's drinking water distribution network infrastructure is outdated and uninformed, and there is no current map of the network that allows one to track its evolution in space and time. Several authors (Shamsaei et al. 2013; Mutikanga et al. 2009; Mvongo et al., 2023) indicate that controlling water loss and managing system operations in an "unplanned" water distribution network are complex and significant sources of nonrevenue water in cities. The majority of pipe materials (steel, cast iron, PVC, etc.) have deteriorated over time. Previous research (Rezaei et al. 2015; Hu & Hubble 2007) has shown that pipe age increases failure rates and water loss. However, age alone is a poor indicator of the necessity for replacement or rehabilitation (Mesalie et al. 2021). Several authors (Ciottoni 1983; O'Day 1983) have shown that age is not as important a factor in pipe breakage as might be expected and that higher failure rates are experienced in smaller-diameter pipes.
A high level of NRW in Cameroon is also influenced by a high level of poor operation and maintenance policies, including ineffective record keeping systems, inadequate technical skills and technology, and water meter inaccuracies. High levels of NRW cause an intermittent supply and therefore pose a significant public health risk. In fact, high water losses often lead to intermittent supplies, either because of limited raw water availability or because of water rationing, which may be needed to reduce supply hours per day. In addition, intermittent supply of water poses a significant health risk, as contaminated groundwater can enter leaking pipes during supply interruptions and very low-pressure periods. A study on pathogen intrusion in water distribution systems revealed that main breaks, despite best efforts to repair such breaks using good sanitary procedures, represent an opportunity for contaminants to enter the distribution system (Karim et al. 2003).
The NRW significantly reduces the amount of water available for allocation. It also impacts the financial viability of the water utility through lost revenue and increased operational costs. Indeed, as of December 31, 2020, a liquidity ratio of 0.89 indicates that Camwater's activities do not generate enough cash to meet short-term commitments, while a solvency ratio of 2.2 indicates high long-term debt relative to the level of equity (CTR 2021). This situation is partly explained by the administration of water prices in Cameroon, which generates a shortfall that is not systematically covered by the state. Thus, Camwater's performance could be improved by either applying the actual prices or systematically covering the loss of earnings linked to the administration of the said prices each year. In addition, unpaid consumption bills, starting with those of the state, hamper Camwater's performance. Indeed, although state receivables have fallen sharply since 2018, from 45.6 billion CFA francs (USD 70.8 million) to 15.4 billion CFA francs (USD 23.9 million) on December 31, 2020 (CTR 2021), they still remain significant.
The NRW also reduces a utility’s capacity to fund service expansion, especially for the poor, which is clearly unacceptable. NWR, or water loss, is not only an engineering problem but also reflects a sociocultural situation that requires changes in community behavior and attitudes toward water usage (Frauendorfer & Liemberger 2010). It is important to address the behavior of the community in the fight against water losses in the network. Certain community attitudes favour illegal connections to the network (fraud) and the theft of equipment such as meters and their accessories. Since the beginning of 2022, 750 subscriber water meters in Douala, 900 meters in Yaoundé, and approximately fifty meters in Mbalmayo and Maroua have been stolen.