Household water filter use in Ahmedabad

Safe drinking water, a scarce resource (Source: Wikimedia Commons)
Safe drinking water, a scarce resource (Source: Wikimedia Commons)

76 million people lack access to safe drinking water in India thus increasing their risk to mortality from water-borne diseases such as diarrhoea, typhoid, and cholera. The poor are much more likely to be affected by unsafe drinking water than those who are financially better off.

The report titled 'Household water filter evaluation, Ahmedabad, India' published by the Comprehensive Initiative on Technology Evaluation (CITE) at the Massachusetts Institute of Technology (MIT), informs that in such a situation, household water filters could serve as a useful frontline tool in ensuring safe drinking water, and have the potential to improve the quality of water when used correctly, consistently, and continuously. However, it is important to understand the factors that influence the choice and consistent use of effective filter designs available in the market by the consumers.

The report presents the findings of a study that explores factors affecting household filter use in the city of Ahmedabad, Gujarat. Ahmedabad Municipal Corporation, a local government body responsible for providing civic infrastructure, has gone at great lengths to provide clean water to its residents, and piped water is often supplied for free to the poorest sections of the population in the city. However, piped water supply faces a number of challenges and requires frequent repair and maintenance due to leakages, pump failures and electrical outrages. These interruptions in water supply have been found to be linked to frequent outbreaks of cholera and other waterborne diseases. The surface water and groundwater in the city is also found to be highly contaminated.

Although water filters are widely available in the markets, there seems to be a considerable lack of demand and information on the usefulness and effectiveness of the different type of filters. This study thus aimed at exploring:

  • the kinds of water filters available in the market in Ahmedabad and their use by the people from different sections of society;
  • the effectiveness of the filters; and
  • factors affecting the choice of filters

The study used a variety of methods to collect data for evaluation including laboratory and field tests of the water filter performance, surveys of water filter retailers and households in Ahmedabad and semi-structured interviews with original equipment manufacturers and distributors in Ahmedabad and Gandhinagar.

Findings of the study

  • Although over 100 models of household water filters were available in Ahmedabad, three types were most commonly used--conventional particle filters such as jali or mesh cloth, gravity non-electrical water filters and reverse osmosis filters.
  • Ahmedabad’s poorest families most commonly used conventional particle filters such as jali mesh or cloth as these were low cost and most widely available.
  • However, jali and mesh cloth filters were largely found to be ineffective at removing harmful elements such as E.coli and total coliform. Jali mesh filters proved even less effective than cloth filters and many a times, these filters actually led to contamination of clean water entering the filter with total coliform.
  • Users of cloth or jali mesh filters had very little or no information about other, better performing water filters that might be affordable at their income levels.
  • The performance of gravity non-electric filter models far surpassed that of cloth and jali mesh filters, but varied by models in terms of E.coli removal, turbidity removal, flow rate, and filter lifetime.
  • The purchase price for even the most affordable water filters in terms of total cost of ownership amounted to several months of income for Ahmedabad’s poorest families. Monthly payment options or interest free financing were offered by less than 20% of retailers, and the purchase price for gravity non-electric products was below the minimum amount for third party creditors. This posed as a serious barrier to filter adoption among users with limited or no savings.
  • Low priced products did not reach rural populations. For example, the relatively more affordable gravity non-electric filters were not readily available in rural areas outside of Ahmedabad, while the more expensive reverse osmosis models were more prevalent in this area.
  • Reverse osmosis filters were the most effective of the three and were found to dramatically reduce total dissolved solids and also remove more than 99.99% E.coli. The Dolphin brand was the most popular one among these.
  • Despite the appeal of clean water produced by reverse osmosis filters, these filters produced a large volume of wastewater, which was thought to be environmentally unsustainable for Ahmedabad, or other water-stressed regions of India.

The report ends by making some recommendations to bring about a change in the current situation that includes the following:

  • Need for information sharing to help Ahmedabad’s poor better understand their water quality and water filter effectiveness.
  • Further exploration of creating new water filters designed for the poor.
  • Improving accessability of gravity non-electric filters to the poor.
  • Need to explore the Dolphin filter supply chain further.
  • Have another look at the environmental effects of reverse osmosis filters.

A copy of the paper can be downloaded below.