Every millimetre of rain that falls on one square metre of roof equals one litre of water.
Enter your roof size below to estimate how much rainwater you could collect in a typical year, how many Wade 23,000 litre tankfuls that represents, and what it could be worth.
Use the approximate horizontal area of the roof that will drain into your tank.
Enter a reliable long-term annual rainfall figure for your location.
Includes an allowance for normal rainwater collection losses.
Equivalent to potentially filling a Wade 23,000 L tank 8.4 times across the year, provided water is being used and storage capacity is available.
How do you currently get your water?
Replace the example figures with the price and load size charged by your water supplier.
Starting figure based on Dargaville's variable water charge. Replace this with the variable water-use charge shown on your bill.
Approximate equivalent cost at the water price entered above.
This is an indicative comparison only. It assumes collected rainwater is used and would otherwise have been purchased at the cost entered above. Actual savings depend on rainfall, water use and available storage.
Every millimetre of rain falling on one square metre of roof produces approximately one litre of water.
The 85% collection allowance accounts for water that may be lost through first flush systems, gutters, overflow and other normal collection losses.
This calculator provides indicative estimates only. Annual rainfall varies from year to year and throughout Northland. Actual rainwater collection will depend on roof area, roof configuration, rainfall intensity, guttering, first flush systems, overflow, tank capacity and water usage. Financial estimates do not include delivery, earthworks, pumps, plumbing, electrical work or other installation costs.
Rainfall figures use selected NIWA 1981–2010 climate station normals and may differ from conditions at your individual property.
The Wade 23,000 L Oval Water Tank gives you substantial storage for rainwater collected from your roof. Its oval shape also keeps the tank narrow for easier transport.
