RainTank2 4.1 can be downloaded from our website for free. The following version: 4.1 is the most frequently downloaded one by the program users. The program's installer file is commonly found as RainTank2.exe. The actual developer of the free software is Dept. of Agriculture and Food. The software belongs to Education Tools.
From the developer:
RainTank 2 is an interactive software tool that has been provided to assist rural communities to estimate water storage and collection needs applicable to a desired level of supply reliability.
RainTank 2 uses actual rainfall data and a simple water balance model to simulate rainfall collection and continuous use over the period of the supplied rainfall data (53 years).
You may want to check out more software, such as StatPlus 2007, Avantage BPM Foundation or QPlot, which might be similar to RainTank2.