This method entails that roof gutters and downpipes deliver water from the house roof to a nearby storage tank. Systems often include a debris trap or a small filter. At a rain event, the first flush of (polluted) precipitation is to be diverted as it may contain leaves or bird droppings from the roof. Gutters often feature a trapezoidal shape with a slight slope made of wood, bamboo, galvanized iron or PVC.
In Kwale school project in Kenya it was found that gutters need to be of good quality and well mounted. For a supply to a 100 m3 tank, the capital investment and works arrived at USD 6.000.
Caretaker needed for regular system check and for diverting first flush of precipitation, checking on cleanliness and leakages of piping. If case of communal use: elected committee for finances and O&M activities. External follow-up support for water quality, training needed. Access provision to credit facilities required.
Risk for contamination should be considered. It is an ecologically sustainable water winning option. Possible in almost every climate, but not always adequate to cover year-round needs. Seasonal changes in precipitation may also require alternative water sources.
First ~20L of rainfall to be diverted to avoid roof contaminants (dust, leaves, insects and bird droppings). Gutters, debris trap or filter media (gravel or charcoal) needs regular cleaning. Occasionally, gutters and pipes need to be checked for leakages. Gutter design and construction requires skills.
Lack of widespread use and operational activities require local awareness-raising programs. Organization at household or shared household level is recommended. Costs may be decisive in finding optimal implementation level. Regular cleaning of gutters and filters ensures no adverse health effects.
No relevant remarks for Gravitational roof catchment gutters and pipes.