Comparative study of rainwater quality in urban Zambia

Five rainwater harvesting systems were installed in two peri-urban areas of Lusaka, the capital city of Zambia, consisting of six ferrocement tanks. Water samples were collected from the direct rain, roof and tank. In order to compare the rainwater quality with water from other sources, samples were also collected from piped water, boreholes and shallow wells. Rainwater was of higher quality than catchment and storage rainwater. However, harvested rainwater in tanks showed the best bacteriological quality probably due to the elimination of contamination by the first flush. The pH in the storage water was higher than that in rainwater and catchment water due to the reaction with the ferrocement tank. However, it was expected that as the ferrocement tanks matured, pH would drop in the storage water and probably meet the World Health Organisation (WHO) guidelines.