How to start rainwater harvesting in an existing building?
Currently a lot of existing buildings do not have systems through which they can harvest rainwater but can start doing so easily with a few simple steps.
Step 1: Identify a suitable catchment area
- In most of the cases, the roof of an existing structure is best suited as a catchment area for rainwater harvesting.
Step 2: Estimate Rainwater Harvesting Potential
- Estimating the rainwater harvesting potential from the catchment area helps fashion and install a correct storage or collection tank for the harvested rainfall.
- Formula to estimate Rainwater Harvesting Potential = Surface Area of catchment (sq. ft.) x Runoff Co-Efficient of Catchment Surface x Amount of Rainfall (mm)
- Or the following calculator can also be used to estimate the rainwater harvesting potential:
Step 3: Select or Design Water Storage or Collection Tank
- It is difficult to select the correct size of a storage or collection tank in an existing building.
- Size of tank is affected by:
- Available Space
- Estimated Rainwater Harvesting Potential
- Purpose of the harvested rainwater
Step 4: Connect existing Plumbing services of the building to selected tank
- Every structure installs plumbing services such as PVC pipes to direct rainwater falling on the rooftops to the catch basins of buildings.
- In most cases, the same pipelines can be used to direct the rainwater from the roof to the designed or selected water storage/collection tank.
Step 5: Start Rainwater Harvesting