THE EFFECT OF TYPE OF WATER-SUPPLY ON WATER-QUALITY IN A DEVELOPING COMMUNITY IN SOUTH-AFRICA

Efforts to provide water to developing communities in South Africa hav e resulted in various types of water supplies being used. This study e xamined the relationship between the type of water supply and the qual ity of water used. Source (communal taps, private outdoor and indoor t aps) and point-of-use water samples were examined for heterotrophic pl ate counts (HPC), total and faecal coliforms, E. coil, and coliphages. Ten percent of samples were also analysed for enteric viruses, Giardi a and Cryptosporidium. Approximately 320 households were included in a case-control study. In addition, a cross-sectional study was conducte d. Both studies examined the relationship between different types of w ater facilities and diarrhoea among pre-school children. The source wa ter was of good microbial quality, but water quality was found to have deteriorated significantly after handling and storage in both case an d control households, exceeding drinking water quality guideline value s by 1-6 orders of magnitude. Coliphage counts were low for all water samples tested. Enteric viruses and Cryptosporidium oocysts were not d etected. Giardia cysts were detected on one occasion in case and contr ol in-house samples. Comparisons of whether in-house water, after hand ling and storage, complied with water quality guideline values demonst rated households using communal taps to have significantly poorer qual ity than households using private outdoor or indoor taps for HPC and E . coli (chi(2)=14.9, P = 0.001; chi(2) = 6.6, P = 0.04 respectively). A similar trend (although not statistically significant) was observed for the other microbial indicators. The cross-sectional study demonstr ated an apparent decrease in health risk associated with private outdo or taps in comparison to communal taps, This study suggests that a pri vate outdoor tap is the minimum level of water supply in order to ensu re the supply of safe water to developing communities. (C) 1997 IAWQ. Published by Elsevier Science Ltd.