3. Methodology
To accomplish the objectives specified above,
it was necessary to obtain rainfall data, potable
water supply, population and number and area
dwellings in each governorate. Then, the total
roof area in each governorate was calculated
based on the average area of different dwellings
and their number. The potential rainwater harvesting
volume is estimated based on the total
roof area, the average annual rainfall, and the
runoff coefficient. Then the potential saving
percentage is calculated by dividing the potential
volume of harvested rainfall by the annual
domestic demand. Moreover, water samples from
60 cisterns from Amman and Irbid governorates
were collected and then several physical, chemical
and biological tests were carried out.