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Published on: 01/03/2012

In 2010, RAIN commissioned a study, “Life-cycle costs of rainwater harvesting”, in order to determine the life-cycle costs of rainwater harvesting and assess the benefits of systems in comparison with other water sources. The study, published by IRC International Water and Sanitation Centre, found that rainwater harvesting has the potential to play an increasingly important role in sustaining water services delivery in many parts of the world. However, the study found that most existing cost data on rainwater harvesting and other water supply systems is limited to initial hardware costs of constructing the system.

Costs over time

Some essential cost information, related to system lifetime, capacity building, institutional development and establishment of micro-credit systems is hard to find. Martine Jeths works in Ethiopia for RAIN on small-scale rainwater harvesting projects and capacity building of local organisations. She finds that “understanding these costs is important for our advocacy because the upfront costs are quite high. But when you look at the entire life-cycle, it is not expensive.”

Charles Batchelor, one of the study’s authors, clarified that to make good comparisons between rainwater harvesting and other technological options, one needs to also get a feel for the longer term recurrent software and hardware costs per person per year. Some of these costs are the cost of providing direct support to those managing and using the systems and the cost of major rehabilitation, i.e. capital maintenance expenditure. Depending on circumstances, rainwater harvesting may be a good alternative to borewells or piped systems and can also be a good complementary system, but they are not necessarily less expensive. A crucial point for Charles Batchelor is that costs of supply should be calculated in terms of litres per person per day and not just total storage capacity.

Addressing the gap in information

For Robert Meerman of the RAIN Foundation, the use of evidence in advocacy is important. He explains “at the moment, we do not have enough ammunition, in the form of evidence, to make a convincing financial argument aimed at decision makers who might consider using rainwater harvesting. For example, at the moment, software costs are not readily available and there is not enough data collected globally to validate our rule of thumb that these software costs are around 10% of capital costs.”  A full financial comparison of water supply costs with other approaches in relation to services provided is simply not possible at the moment.

RAIN Foundation is now working with partners in order to start addressing the gap in life-cycle cost information of rain water harvesting in their programmes and partnerships. The life-cycle costs approach also seeks to improve sector understanding of why life-cycle costs assessment is central to improved and sustained water services delivery and to ensure life-cycle unit costs are mainstreamed into practice. 

Spreading the word

The Dutch WASH Alliance consortium with RAIN, Simavi, Akvo, AMREF, ICCO, and WASTE has defined five dimensions, referred to as FIETS, in their approach to sustainable WASH. The first of these is financial sustainability. “Financial sustainability refers to providing innovative financial concepts which minimize dependency on external subsidies. Business approaches and private sector involvement are used in an optimal way, strengthening the ‘in-country’ structural finance for WASH services.” According to Robert Meerman, financial sustainability should include the life-cycle costs approach to sustainable service delivery.

RAIN is also applying the life-cycle costs approach to new studies. RAIN is plugging the life-cycle costs information they have into cost-benefit analysis done within the context of the Water Recharge, Retention and Reuse (3R) consortium, which will be published as a 3R booklet.

To get more in-depth field data, IRC and RAIN have embarked on another study, under the MUStRAIN project, which aims to understand the costs and benefits of sand dams and sub-service dams for multiple-use water services (MUS) in Ethiopia. This study will both look at the few existing systems and their actual long term costs. It will also document the life-cycle costs of new pilot projects, with the purpose of estimating the costs and benefits of large scale implementation. A before and after evaluation of water service delivery levels and benefits will allow a more meaningful comparison of these systems with other approaches.

RAIN also focuses on knowledge exchange on rainwater harvesting on a global scale. Although studies like the one in Ethiopia help, Robert Meerman explained that RAIN has the ambition to play a central role in collecting and organising life-cycle cost information from around the world. Ultimately, it is only through combining information and knowledge in a larger global network that it will become possible to fill information gaps.

While the original study did not provide enough ammunition for advocacy, it is clear that there is an increased recognition of the need to collect and document life-cycle costs and measure the service delivered within RAIN and like-minded organisations. Within RAIN itself, there may be opportunities in the future to systematically collect more life-cycle costs and service level information with the development of new project management systems and standards like IATI. According to Robert, on the one hand, “we are not pro-actively using the outcomes of the original study in terms of advocacy, but on the other hand, we are now working with partners to improve cost information and we have a different perspective on the financial issues around rainwater harvesting.”

Nicolas Dickinson, 29 February 2012

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