Rainwater Tank Selection Tool for Industrial and Residential Applications
The tool enables users to select the optimal solution from GRAF’s wide range of underground rainwater harvesting tanks in just a few simple steps. It supports the selection of flat tanks with capacities ranging from 1,500 to 25,000 litres and cylindrical tanks from 2,700 to 56,000 litres. By combining real rainfall data with project-specific parameters, users can accurately determine the required storage capacity and select a rainwater harvesting system tailored to the needs of their project.
The application supports the design of rainwater harvesting systems for a wide range of projects, from single-family homes and residential developments to commercial and industrial facilities. It takes into account various intended uses of harvested rainwater, including garden and landscape irrigation, toilet flushing, laundry, and other non-potable applications. The tool helps determine the optimal tank size while also estimating the potential water and cost savings resulting from efficient rainwater use.
Once the selection process is complete, users receive a summary of the key technical parameters of the recommended solution, including the selected tank capacity and the estimated utilisation of harvested rainwater. They can also generate a comprehensive PDF report containing the selection summary, a functional system diagram, and essential information about the recommended tank.
The application available in Poland.
Rainwater Harvesting Tank Capacity Calculation
How do you determine the required rainwater tank capacity using the selection tool?
To select a GRAF underground rainwater harvesting tank, users need to provide a set of basic project parameters describing the site conditions, the intended use of harvested rainwater, and the catchment area from which rainwater will be collected. The tool considers both local site conditions and individual project requirements, making it possible to select a solution that ensures efficient rainwater storage and utilisation.
The following information is required to perform the calculation:
- Tank installation parameters: maximum available installation length and width, minimum soil cover depth, tank inlet elevation, and inlet diameter.
- Site conditions: site type and groundwater level.
- Intended use of harvested rainwater: garden irrigation, laundry, toilet flushing, and other non-potable applications.
- Water demand parameters: garden area, irrigation intensity and frequency, and irrigation period.
- Catchment parameters: roof area and roof surface type, defined using the runoff coefficient (CN).
In addition, users can take advantage of an interactive map, which allows them to quickly determine the roof area or the area intended for irrigation without the need for manual measurements.
Based on the entered data, the tool analyses the balance between available rainfall and the projected rainwater demand, then recommends the most suitable GRAF tank configuration for the project.
Rainwater Harvesting Tank Selection Results
Based on the provided project data, the tool calculates:
- the optimal rainwater tank capacity, matched to the local rainfall balance and the projected water demand,
- the recommended GRAF tank configuration that meets the project requirements,
- rainfall parameters for the selected location, including total rainfall and the effective rainfall available for harvesting,
- the projected water deficit and losses resulting from the system’s limited storage capacity,
- the potential savings in potable water consumption achieved through the use of harvested rainwater,
- the technical parameters of the selected solution, including total storage capacity, number of tank segments, number of rows, installation dimensions, and installation depth,
- a storage capacity balance, allowing users to evaluate how well the selected tank matches the actual water demand.
For indoor non-potable applications such as toilet flushing, laundry, and other utility uses, rainwater can be most effectively managed using rainwater management units, which provide a complete solution for the distribution and control of harvested rainwater. GRAF also offers free technical support in selecting the most suitable rainwater management unit for a given project.
The tool also presents the recommended GRAF rainwater tank options together with their key technical parameters, allowing users to compare available solutions and select the configuration best suited to the site conditions and the intended use of harvested rainwater.
The results can be saved or downloaded as a comprehensive PDF report containing a summary of the calculations, the technical specifications of the selected tank, and a preliminary product recommendation.
The generated report can serve as a valuable reference during the investment planning stage and as supporting documentation for projects involving sustainable stormwater management and rainwater harvesting systems.
