Cistern capacity calculator
Use your measured daily consumption and the period you want to cover between refills. Include the reserve you have chosen for possible delays.
Result
Enter daily use and days of coverage to see the estimate.
How to use the result
Required capacity = daily use × days of coverage. For example, 500 L per day for 7 days requires 3,500 usable liters. With 5,000 usable liters and the same consumption, the capacity-to-use ratio is 10 days.
That ratio helps with volume planning. It does not measure the age of all the water or establish drinking-water safety, because water from different refills can mix. Changes in occupancy, irrigation, pool use and leaks also affect the calculation.
Before buying or building, review usable capacity, available space, structural requirements, maintenance access and delivery volumes with the person designing the installation. Follow the selected model’s instructions.
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