Water Supply and Access

Why is water supply important?

As a result of a number of past studies we began to develop a body of evidence which suggested that programs to improve water quality only are unlikely to have a significant health impact. Instead these studies suggested that a much greater health impact could be achieved by improving hygiene. One of the most simple and obvious ways to do so is to make it more water use more convenient and easy to access.

Being able to access water at a nearby location offers various other non-health benefits. It can often result in time savings – time that could instead be invested in education or increased work productivity.  Secondly having a water point closer to home can potentially mitigate the security risks and vulnerability women and children often face when collecting water.

Our key contributions and research in this area:

The Water Use Plateau

This theory, which describes the relationship between the distance an individual must travel to reach a water source and the amount of water they consume, has been utilised by the EHG and others since the 1970s and was documented by Cairncross and Feacham in 1993.plateau

According to this model, when water sources are more than half an hour’s return journey away from home, then provision of water closer to the home will lead almost automatically to water consumption increases, but sources less than a 30 minute round-trip away will be used for almost the same amount of water whether the distance is 1000 metres or 100 metres. Despite this inelasticity of demand, when water is piped into the house or yard, the convenience of access results in consumption rising dramatically. Based on this simple diagram, interventions to improve water supply should be targeted at those people who are ‘off the end of the plateau’ since closer water supplies will lead their consumption to increase – hence their hygiene to improve – and they will therefore be more likely to show a health benefit. For those on the ‘plateau’ it is only the installation of house connections that is likely to yield an increases in consumption and therefore a health benefit.

Measuring distance and access as criteria for ‘improved’ water sources water carry

Despite acknowledging that water quantity is important to health, to date the Joint Monitoring Programme (JMP) which assesses progress towards the Millennium Development Goals on water and sanitation, only considers water quality as an indicator of an ‘improved water source’. This study utilised existing Demographic Health Survey (DHS) and Multiple Indicator Cluster Survey (MICS) data from 39 countries in sub-Saharan Africa to consider progress against the MDG indicator should distance to water source also be considered. The study found that with the subsequent inclusion of water collection time, the number of people with access to improved water sources within 30 minutes of their residence was 90 million, down from 160 million. This implies that 70 million people, roughly 10% of the region’s population, supposedly had access to ‘‘improved’’ water sources but had to spend well over 30 minutes to collect water from those water sources. It is arguable that those 70 million people effectively did not have access to water.

Our current projects in this area:

Bore hole provision in Pakistan

Currently we are collaborating with Osman Dar and Mishal Khan on a project in Pakistan which hopes to measure the health and non-health impacts of improving water access to those who are ‘off the edge of the plateau’ – those who travel for more than a 30-minute round trip to collect water. This will be an randomised intervention study which will provide bore holes in conjunction with a local Pakistani NGO.

Evaluation of household water connection program in Vietnam

This was an evaluation of Watershed’s piped water supply program in Vietnam. The study assessed the drinking water quality and health impacts of piped water systems where access to ‘improved’ water sources is already good. This was a longitudinal, prospective cohort study followed 300 households in seven project areas in Da Nang province, Vietnam. 224 households of these households paid for an on-plot piped water connection and 76 control households from the same areas rely on the existing ‘improved’ water sources outside the home. The evaluation found that households connected to a piped water supply had consistently better drinking water quality than those relying on other sources, experienced less diarrhoea.

Full list of publications related to water supply


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