tank [10]. Fig. 2 shows a schematic of a rooftop
catchment system in Jordan. The collection area
in most cases is the roof of a house or a building.
The effective roof area and the material used in
constructing the roof influence the efficiency of
collection and the water quality. Smoother,
cleaner and more impervious roofing materials
are preferred; they contribute to better water
quality and greater quantity. Tiled roofs or roofs
sheeted with corrugated mild steel etc., are preferable
since they are the easiest to use and give the
cleanest water [11].
Cement and tiled roofs are the most common
roofs used in Jordan. These types of roofs have
good durability, relatively low price, and provide
good quality water. Regardless of the roof material,
many designers assume about a 20% loss of
annual rainfall. These losses are due to roofing
material texture, evaporation, losses occurring in
gutters and storage tanks, and inefficiencies in the
collection process.
A conveyance system usually consists of
gutters or pipes that deliver rainwater falling on
the rooftop to cisterns or tanks. Gutters or pipes
must be properly sized, sloped and installed in
order to maximize the quantity of harvested
water the most common materials of gutters are