RCC Unit year space garden saving number Demand inches masonry Plastic gallons Security watering GI sheet rooftops Concrete chemicals 500 liters variations Fiberglass 240 liters indoor use UV exposure outlet pipe square feet ferrocement algae growth distribution ground tanks larger tanks higher level welded seams indoor supply proper lining Surface tanks potable water various sizes Tank Placement family members Catchment Area Stainless Steel allegianceindia rainwater tanks various factors raised platform water use habits intended purpose shorter lifespan Common materials specific coating higher elevation Galvanized Steel conversion factor cleaning purposes sole water source small rain barrels polyethylene tanks potential rainwater event rainfall depth Allegiance Enterprise average annual rainfall waterproofing materials reliable water availability Allegiance Water Management Æ Water Management Tank Size local environmental conditions Rain Water Harvesting Storage Tanks