American Rainwater Catchment Systems Association, ARCSA, A non-profit organization founded to promote rainwater catchment systems in the United States.

Rain Water Systems in partnership with the not for profit organization No Thirsty Child has installed eleven hundred gallon systems in seventeen locations in the Western part of Rwanda around Lake Kivu. Their goal is to do 98 more in the Karongi district. The rain water is primarily used as a source of clean drinking water and Sawyer filters are also provided.
In addition to the rain water harvesting systems No Thirsty Child provides health and hygiene training. The locations are usually at churches where there are larger roof structures. The area we work in gets 43" of rain annually but there is no safe water to drink and even in the capital of Kigali residents are warned to boil there water.
We see people walk for miles carrying heavy containers with contaminated water and many children die every year from water borne illness. A typical church gathering water from half its roof area provides an average of forty thousand gallons of rain water per year.
You can see more images here.