Practical
Rainwater Harvesting Calculator
Calculate annual rainwater collection potential from roof area and local rainfall
Rainwater harvesting collects roof runoff for garden irrigation, toilet flushing, and laundry. UK average rainfall of 600-1,200mm annually can supply 30-50% of non-potable water needs.
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Tip: A simple water butt connected to a downpipe is the easiest and cheapest way to start harvesting rainwater - no plumber required.
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Fun Fact
Sydney, Australia mandates rainwater tanks in all new construction. In some regions, collected rainwater supplies 40-60% of household needs.
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