Download of HydroOffice 2012 was on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The actual developer of the free software is HydroOffice.org.
The following version: 2012 is the most frequently downloaded one by the program users. The program lies within Education Tools, more precisely Science Tools. The default filename for the program's installer is HydroOffice.exe. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
HydroOffice is a comprehensive software package designed for hydrology, hydrogeology, meteorology and environmental engineers. The HydroOffice package contains a number of separate installable tools which are distributed as freeware or are priced.
You may want to check out more software, such as StatPlus 2007, Avantage BPM Foundation or Adding Machine, which might be similar to HydroOffice.