Main characteristics Rooftop WH:

• consists of roof, gutters, ‘first flush’ device and above or below ground storage tank
• useful in areas with rainfall between 200 and 1000 mm. Especially good in areas with two separate rainy seasons (bimodal)
• high runoff coefficient (0.5 to 0.9)
• mainly used for domestic purposes
• may recharge groundwater if an infiltration well is built
• quality of water can be controlled by flushing away the first collection (from a dirty roof) filtration and simple disinfection techniques
• collected water is normally acceptable both in terms of taste and appearance
• provides water next to homes
• the user has control

Main characteristics Courtyard WH:

• consist of catchment area, retention and conveyance structures and above or below ground storage tanks;
• useful in arid and semi-arid region (rainfall between 200 and 750 mm) – even semi-desert (< 200 mm)
• for domestic use and livestock consumption mainly
• quality of water can be controlled by flushing away the first collection (from a dirty roof) filtration and simple disinfection techniques
• provides water next to homes
• the user has control

Main benefits

• Increased availability of relatively clean, reliable and affordable water for drinking, domestic use, sanitation, animal consumption, irrigating kitchen gardens and other income generating activities
• Reduced workload especially for women, who are responsible for many household tasks and thus reduced women’s health problems connected to carrying water
• Possibility of storing water during the rainy season and using it during the dry season
• Management of water at household level and therefore avoiding water conflicts related to water management at the community level

Main disadvantages

• Possible danger of contamination of water such as high level of phosphate from bird drops and dust accumulated on a house roof, which is washed into the storage vessel
• Reliance on relatively reliable rainfall and adequate storage capacity

(Mekdaschi & Liniger 2013, African Development Bank 2009; Oweis et al. 2012)