Due to scarcity of potable water, rainwater harvesting from rooftop has been
favoured as an alternative source of water supply by most rural communities in Nigeria. This
study investigated the physicochemical and bacteriological characteristics of rainwater
harvested from three different rooftop sheets in Esan West Local Government Area, Edo State.
Parameters investigated include pH, TSS, TDS, Turbidity, Acidity, Ca2+, Fe, Pb, Cr, TBC, TCC
and
E-coli
. The results showed that mean values of harvested rainwater from all sampled
rooftops are acidic especially at the onset of the raining season. TSS and TDS were highest in
samples collected from Asbestos rooftop, followed by Aluminum rooftop while samples from
galvanized Iron had the least irrespective of the rainfall event. Rainwater samples collected at
the onset of rain had higher Ca
2+ concentration than those collected at the peak of rain for all
roof type with galvanized Iron rooftop catchment recording the highest concentration. Samples
collected at the onset of the rain for all roof type had Fe concentrations above the WHO limit of
0.1mg/l while those collected at the peak of rain had lesser values. Values of pb, Cr were within
WHO permissible limit. Analysis of microbial parameters revealed that samples collected from
all rooftop and for both seasons exceeded WHO limit of <100cfu/ml for TBC. Rainwater
samples collected from corrugated Asbestos rooftop had the highest bacterial load for both onset
and peak of rain, followed by samples collected from Aluminum rooftop for the onset on rain.
E-coli count was highest in water sample collected from corrugated Asbestos rooftop for onset
and peak of rain. The Analysis of variance (ANOVA) shows that quality of rainwater harvested
from galvanized Iron, Aluminum and Asbestos rooftop catchments does not significantly differ
at 0.05 statistical thresholds among rooftop catchment although samples from asbestos rooftop
catchment recorded highest contamination level. In view of the physicochemical and
bacteriological results, harvested rainwater can be put to all forms of domestic use except for
direct ingestion unless treated. © JASEM
