?The quantity of available stored water is limited by the size of the rainfall Catchment area and storage
capacity.
?The user/s must learn to ration use of water during dry seasons
?Inadequate maintenance can lead to contamination of the stored water
WHY FERRO CEMENT?
Ferro cement technology is extremely simple to implement and semi skilled workers can learn it with ease.
It can be used to construct a tank for storage of safe drinking water. It has a high degree of impermeability
and resistance to cracking and has a long life. Ferro cement requires only a few easily available basic
materials: cement, sand, Galvanized Iron (GI) wire mesh and Mild steel (MS) bars in small amounts and is
cost-effective. Ferro cement is thinner and lighter than poured concrete and has greater tensile strength
and flexibility than ordinary concrete because it has wire reinforcement distributed throughout the
structure. It is relatively more economical than steel or concrete. Its maintenance is minimal and less
costly and easy to repair in case of local damage. The Ferro cement rainwater harvesting tank detailed in
this document consists of a skeletal cage that is overlaid externally and internally with a cement rendering
CONDITIONS FOR ADOPTION
?Rainwater harvesting from roof tops is most suited to areas of water scarcity. This may be due to
low annual rainfall or potable water sources being too distant from users and sometimes difficult or
expensive to carry or transport.
?Adequate seasonal rainfall must be available in the area. For example during the monsoon period/s.
?The roof must be adequately sloped RCC flat roof (20), clay tile (min. 300), and corrugated sheet
roofing (min. 100). Thatch roof is unsuitable because of problems of dirt and other contamination.
?A catchment area (roof) of 160 to 215 sq. ft. (15 to 20 sq. mtrs) or above is sufficient.
?Roof gutters must be adequately sloped to facilitate flow of run off water from roof to down pipes
that lead to rainwater collection tank. Gutters must be at a higher level than the mouth of the tank.
?Simple water diversion mechanism must be used to direct unclean water away from the collection
tank as and when needed.
OPERATIONAL PRECAUTIONS
In order to have potable drinking water, the following precautions must be taken:
?Smooth roof surface without excess debris (leaves etc.) is desirable for easy flow of water
?The roof should not be under trees or to close to overhanging branches of trees to prevent dirty
leaves and bird droppings from falling on it.
?Gutters must be kept free of dirty leaves etc. to promote free flow of run-off water
?The tank must be properly sealed to keep out mosquitoes, lizards and other insects and vermin.
?Ensure that sunlight does not enter the tank
?Before the onset of the monsoon or rainy period or after two rains, the roof and gutters should be
properly cleaned and water diverted away from the storage tank when cleaning. Also the rainwater
must be briefly diverted at the time the rain begins to fall at the start of the rainy period. This will
ensure that only clean water is collected.
?Filters must be cleaned periodically to remove impurities and dirt etc.
?The Ferro cement tank must be cleaned periodically, at least before each rainy season
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