Área captação (m²)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
m² × mm × 0.8
About this calculator
The Rainwater Catchment Area calculator is an essential tool for optimizing water resource usage in construction projects. It calculates the required catchment area to collect a specific amount of rainwater, considering regional rainfall and a runoff coefficient. The formula used is straightforward: multiply the desired catchment area (in square meters) by rainfall (in millimeters) and an efficiency coefficient, usually 0.8.
The catchment area is vital in sustainable construction projects, as it enables the collection and storage of rainwater for non-potable uses, reducing demand for treated water and minimizing environmental impact. The calculator helps determine the necessary area to meet specific project needs, considering local rainfall and system efficiency.
When using the Catchment Area calculator, it's crucial to keep some precautions in mind. Rainfall can vary significantly from year to year and region to region, so it's essential to use reliable and up-to-date rainfall data. Additionally, the runoff coefficient can be affected by factors such as catchment surface type and obstacles.
With the Catchment Area calculated correctly, it's possible to design efficient rainwater collection and storage systems, contributing to sustainability and water efficiency in construction projects.
Frequently asked questions
What is the runoff coefficient?
The runoff coefficient represents the efficiency of the rainwater catchment system, considering losses due to evaporation, infiltration, and other factors.
How do I determine my region's rainfall?
Rainfall data can be obtained from historical records of nearby weather stations or specific rainfall studies for your region.
Can I use the calculator for any type of catchment surface?
The calculator provides a general estimate. However, different catchment surfaces (roofs, pavements, etc.) may have varying runoff coefficients, affecting system efficiency.
Is the calculated Catchment Area fixed or can it vary?
The calculated Catchment Area can vary according to changes in rainfall, runoff coefficient, or project water needs.
Does the calculator consider the quality of the captured water?
No, the calculator focuses solely on the quantity of water that can be captured. Water quality depends on other factors, such as catchment surface type and storage conditions.