March 2022 – Ask for Water GmbH

Corrosion is the attack of the surface of materials by chemical processes and affects concrete, glass, plastic and materials that contain iron. In water supply distribution systems, corrosion is the partial dissolution of the materials that make up the treatment and supply systems. In certain circumstances, all water can be corrosive. Corrosion may lead to structural failure and leaks, as well as deterioration of chemical and microbial water quality. The World Health Organization (WHO) does not provide guideline values for iron in drinking water. The WHO acknowledge that corrosion control is an important aspect of the management of a drinking water system but does not explicitly refer to corrosion concerns in the case of handpumps or sources that rely on other groundwater water-lifting technologies.

Rusted pipe on an India Mark II handpump (Source: Larry Bentley)

Research into corrosion in West Africa within the Handpumps Project of the World Bank in the 1980s concluded that: (i) total iron concentration in natural groundwater is rarely greater than 1 mg/l; (ii) corrosion is usually the cause of the red water (iron) problem in handpump-equipped wells; (iii) galvanisation does not protect rising mains and pump rods from corrosion under the prevailing groundwater conditions in the subregion (pH < 6.5); and (iv) the less a corrosion-affected handpump is used, the more serious the iron problem becomes. All of these observations still hold true. In addition to low pH levels, high salinity and high chloride levels can also accelerate handpump corrosion, but less documentation on these phenomena is available. Recent research indicates that there may also be leaching of lead into groundwater from brass/bronze components.

This study finds that communities in over 20 countries in SSA still face the problem of rapidly corroding handpumps (see Figure S1 below). Evidence includes academic research, reports (both old and more recent) and observations that have been shared. To date, there have been relatively few systematic studies of this problem.

There may be cause for optimism in some countries where, despite aggressive groundwaters, the ‘iron problem’ seems to have been addressed (notably The Gambia and Ghana). In some countries governments are taking action to prevent rapid corrosion, such as by banning or trying to prevent the use of galvanised iron (GI) pipes (e.g. Uganda, Zambia and Chad). However, the problem seems to be continuing in many other countries, with varying levels of documentation and research. In Niger, for example, there was a corrosion problem in the past but the current status is simply not known. In Burkina Faso the rapid corrosion problem is well documented but there is a lack of action. There are numerous other countries where the phenomenon has been observed and documented to a limited extent.

The combination of GI pipes or rods and water with low pH will cause the GI components to rapidly corrode. There have been observations of components requiring replacement within a few months to a couple of years, whereas they should last eight to 10 years. While there has been confusion about whether iron observed in groundwater is coming from the aquifer, or caused by the corrosion of the pump itself, simple tests do exist to determine the source. These involve measuring the change of colour in the pumped water.

Preventing rapid corrosion of handpumps may not be as simple as it may appear. A key aspect is ensuring that materials other than GI for riser pipes and pump rods are used in water with low pH levels. Alternatives include certain grades of stainless steel (SS) or, for riser pipes only, unplasticised polyvinyl chloride (PVC). However, the International Specifications and Indian Standards for the India Mark pumps do not include these options and so guidance is quite limited. Furthermore, there are indications that the SS option may cause rapid corrosion of the water tank, while PVC can break and problems are faced with maintenance due to rethreading challenges. Where water levels allow, the corrosion-resistant option of the Afridev pump provides an alternative to the India Mark pump. There are also alternative corrosion-resistant propriety handpumps on the market (i.e. designs that are not in the public domain). Motorised pumps may also be an option, provided that non-corrosive riser pipes are installed. However, introducing a new pump into any setting requires consideration of capital and maintenance costs, supply chains for pumps, and spares and maintenance skills.

Despite its prevalence, rapid corrosion of handpumps is a topic that has remained on the margins of many in-country water supply policies and programmes. Despite the fact that handpumps will continue to remain important for decades to come – particularly for remote, rural populations – the rapid corrosion problem barely features in global discourse. The realities faced by many users have simply not been sufficiently heard. If the ‘iron problem’ continues to be ignored, those living in areas where groundwater has a low pH, high salinity or high chloride will simply be left behind and countries where this is widespread may actually witness drinking water supply coverage levels declining over time.

Rapid corrosion is not only an issue for handpumps, but also potentially for the riser pipes in motorised pumps used for point sources, or which feed into reticulated systems. The realities of rapid corrosion of all groundwater systems need to be better understood and taken into consideration in project design and implementation. Notably, corrosion is not simply confined to rapid or early-life corrosion. All components that are submerged in, or and out of, water will eventually corrode, and so corrosion must be considered as part of the long-term maintenance of handpump (or motorised pump) water supplies.

In order to take the issues raised by this study forward, it is recommended that:

RWSN, other global platforms and international agencies should use the information in this report, as well as the other two reports from the Stop the Rot initiative, as a basis for raising awareness of:
- The ongoing reliance on handpumps in SSA, despite growing interest in groundwater systems that use other energy sources, including solar, and in piped supplies.
- The phenomenon of rapid handpump corrosion, including the causes, effects, impacts and mitigation measures (together with their ongoing challenges).
- The importance of determining whether rapid handpump corrosion takes place in all SSA countries.
- The need to consider corrosion as part of the long-term maintenance of all water supplies that rely on groundwater, including handpumps.
Donor/funding agencies should:
- Ensure that their grantees are aware of rapid corrosion of handpumps, report on it when it is observed or suspected (through monitoring or when undertaking rehabilitation programmes) and support the grantees to understand more about the extent of the problem and actively seek solutions.
- Support academic organisation(s) to develop a continental map and national maps that illustrate the likelihood of low pH values in SSA, incorporating data on population densities where this is available.
- Consider funding organisations and/or consultants to:
  - Document what has reduced or mitigated handpump corrosions in those countries where it has been addressed.
  - Investigate the performance of handpumps whereby components have been replaced in order to prevent rapid corrosion and examine whether the new solutions are viable in the short, medium and long term. Studies should include examination of possible galvanic corrosion of tanks and cylinders or failing UPVC.
  - Document what is happening in countries where there is limited evidence of rapid handpump corrosion, which may be currently ignored.
- In all cases, the information should be made available in the public domain.
National governments and their development partners, as well as other implementing organisations should:
- Ensure that assessment and post-construction monitoring mechanisms incorporate questions about user perceptions of water quality such as taste, smell and appearance and, if concerns are raised, follow up with studies to identify the cause of the problem (which may include rapid corrosion). Ensure that any studies are placed in the public domain.
- Consider the options available to prevent rapid corrosion or to mitigate its effects, such as installing a corrosion-resistant option of the Afridev pump (if required pump depth allows), installing another corrosion-resistant pump, use of SS pump rods and riser pipes or use of UPVC riser pipes and SS pump rods for the India Mark pumps, use of a motorised pump with non-corrosive riser pipes. If there is no option but to use GI pipes and rods, these need to be replaced more frequently.
- It may be necessary to review handpump standardisation policies and standards across the country. In case changes to the components are made that are not in the International Standards, there should be monitoring of pump performance before widescale rollout. Note that any changes in standardisation policy will require investments and support to ensure the availability of spare parts, and to ensure that handpump mechanics, drillers and pump caretakers are trained in the installation and maintenance of variants of existing pumps or new types of pump.
- In the case of new sources, or for rehabilitation, always undertake water quality testing (including pH, electrical conductivity and turbidity) prior to installation to determine whether the groundwater source is aggressive and likely to cause rapid corrosion of GI pipes, pump rods and the pump cylinder.
Lead international agencies should form an action group on handpumps (perhaps incorporating other groundwater lifting methods). The action group should comprise not only international agencies, but individuals and organisations that are trying to preventing rapid corrosion of handpumps in-country. The action group should:
- Provide a platform for learning and exchange on handpump issues (including corrosion) and advocate for investments into studies that examine the effectiveness of alternatives to the installation of GI riser pipe and pump rods.
- Engage in policy dialogue with governments, donor agencies, non-governmental organisations and academics that are working in the countries where rapid corrosion has been identified as a problem.
- Where appropriate, make policy recommendations.
The WHO should expand its guidance on corrosion control to include corrosion mitigation measures for handpumps (and other groundwater lifting installations) in their next update of the ‘Guidelines for drinking- water quality’ and incorporate this issue into the next edition of their ‘Guidelines for small drinking-water supplies’.

For more details, you can access the full report: Danert, K. (2022) ‘Stop the Rot Report II: Rapid corrosion of handpumps. Action research on handpump component quality and corrosion in sub-Saharan Africa’. Ask for Water GmbH, Skat Foundation and RWSN, St Gallen, Switzerland.

This is the second of a series of three reports to bring about action to Stop the Rot.

All three reports are also available in French.

Handpumps have revolutionised access to safe, reliable water supplies in low-income countries, particularly in rural areas. They provide a viable alternative to contaminated surface water, open wells and unprotected springs. The India Mark II pump and the Afridev pump are the two most common community handpumps in SSA, while the Vergnet pump is most likely the third most common handpump in SSA. The people of Zimbabwe rely on the Bush Pump. Based on analysis of the most recent data published by the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) through the Joint Monitoring Programme (JMP), it is estimated that almost 200 million people in SSA (18.5% of the total population) rely on about 700,000 handpumps to provide them with their main drinking water supply. Of this, urban reliance is estimated to be 7.3% whereas rural reliance is 25.9%. Reliance is highest in Malawi, South Sudan, Zimbabwe, Guinea and Burkina Faso, ranging from 42% to 61% of the population.

Figure: Percentage of rural population using a borehole or protected well as their main drinking water supply

Despite their merits, much criticism has been directed to handpumps. Limited ability to transport large quantities of water, coupled with a lack of storage capacity at the home, means that water from handpumps is usually fetched on a daily basis. Handpumps have also made the headlines: in 2010, only an estimated two out of three handpumps in SSA were working; a decade later it was estimated to have only improved to three out of four. When water services fail, there are negative impacts on health and other human development gains, not to mention the burden on users of finding alternative sources.

Interest in other technologies, particular solar pumps and motorised piped schemes for SSA, is growing. However, the handpump asset base in SSA remains considerable and makes a significant contribution to safe and reliable water supplies. An estimated 23% of the SSA population (about 230 million people) still rely on unsafe and distant water sources and many could benefit from a handpump. Moreover, not all hydrogeological settings can support abstraction rates that are much higher than that of a handpump; motorised schemes may consequently be even more challenging to maintain than handpumps. To avoid backsliding in terms of drinking water access, handpumps should be considered alongside alternatives.

There is ongoing interest in water point functionality, with a number of national estimates available that are based on different methods of collection and calculation. Despite the headline figures of non-functionality, there is need for caution in undertaking cross-country benchmarking. The headlines generated by the commonly used binary indicator (functional/non-functional) have stimulated interest and studies on handpump management and maintenance. However, functionality estimates do provide information on how handpumps are actually performing, or why sources are failing.

Tested ways of measuring performance include assessing a sample of sources and using a tiered approach that considers yield, reliability and water quality. In a sample from Ethiopia, for example, although 82% of pumps were working, and thus considered functional, only 59% provided sufficient yield and only 45% were also reliable. Grading water point sources in terms of water availability and other sub-categories is another means of measuring performance. In a sample from within Sierra Leone, 56% of water points were found to be functional, with 17% functioning poorly and in need of repairs or replacement of parts, and 27% of water points were without water and categorised as having a problem with either the pump or the well.

A handpump breaks down for a very specific technical reason (such as the breakage of the chain or an O-ring failing) whereas its repair depends on the ability of the community to raise funds, organise a mechanic and source spare parts. In turn, these depend on other factors within the locality and country.

Particular cause for concern is the sizeable drop in functionality in the first one to two years after installation, which is a common occurrence. This represents a premature technical failure, as even the fastest wearing parts in a handpump should last for the first year. Premature failure means that something went wrong with the engineering – such as the borehole siting, design and/or construction, pump quality or installation, or the pump use – or that there was vandalism or theft. Alternatively, the installation may have been rejected by the users from the outset (e.g. due to the handpump location, or the appearance or taste of the water).

There is a perception among sector stakeholders that handpumps, alongside community management, have not been performing as well as they should have, but to date there is no conclusive evidence or consensus as to which factors are most important for good performance. While there have been many studies into the causes of non-functionality, this report finds that engineering and hardware issues – handpump hardware issues in particular – have not been sufficiently considered in the literature. Based on anecdotal evidence shared by practitioners and some limited studies, premature handpump failure has continued to occur since the 1980s, with rapid corrosion and the installation of poor-quality handpump components among the key causes. However, these issues are not prominent in the global discourse on achieving universal access to safe water. Policy dialogue and political action to tackle these issues is lacking. Notable exceptions include Uganda, where the government has taken measures to militate rapid handpump corrosion.

Rigorous examination of the quality of handpump hardware is not within the scope of assessment tools used today. Removal of the handpump from the ground and its inspection, alongside follow-up of user perceptions of water quality (taste and appearance), would provide useful insights into component quality, rapid corrosion and whether a handpump has actually reached the end of its service life. Not doing so has significantly compounded our understanding of the extent of the problem.

This ongoing lack of emphasis on the physical condition of handpumps may be due to the shift of focus away from infrastructure towards service delivery in the rural water supply sector. With a few exceptions, handpump hardware quality seems to be largely taken for granted.

For more details, you can access the full report Stop the Rot Report I: Handpump reliance, functionality and technical failure. Action research on handpump component quality and corrosion in sub-Saharan Africa’. Ask for Water GmbH, Skat Foundation and RWSN, St Gallen, Switzerland

This is the first of a series of three reports to bring about action to Stop the Rot.

All three reports are also available in French.