Rainwater harvesting calculator
A rainwater harvesting calculator calculator helps you estimate how much water can be collected from a roof over the course of a year. By taking location, roof area, roof material and precipitation into account, you can get a clearer picture of how much rainwater is actually available.
Roof area affects how much water you can collect
The larger your roof area, the more rainwater can be collected. A roof acts as a natural collection surface where rain is directed to gutters and downpipes. From there, the water can be collected in a barrel, tank or other container.
Roof material also matters
Different roof materials allow different proportions of precipitation to run off. A good rainwater calculator therefore needs to take the roof material into account. Metal and slate roofs, for example, can provide higher runoff than some other roofing materials.
Precipitation varies between locations
How much rainwater can be collected depends on more than just the roof. Precipitation can vary greatly between cities, regions and countries. The calculation is therefore more relevant when it is based on precipitation data for the actual location of the roof.
See the results month by month
It is also useful to see how the amount of rainwater varies throughout the year. Rainfall is rarely distributed evenly between the months. A monthly calculation makes it easier to understand when rainwater availability is normally higher or lower.
Use a rainwater harvesting calculator before choosing a tank
A calculation can be a good first step before deciding how you want to collect and store rainwater. With RainTact, you can enter the location, roof area and roof material and receive a report showing the estimated amount of rainwater per year and month. This gives you a clearer basis for planning your collection system.