There was a download of Drains 2018.01 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The program's installer files are commonly found as Drains.exe or Drains64.exe etc.
We recommend checking the downloaded files with any free antivirus. This PC software can be installed on Windows XP/Vista/7/8/10/11 environment, 32-bit version. This program is a product of Watercom. The most popular versions of the software are 2012.0 and 1.0. The software lies within Photo & Graphics Tools, more precisely 3D Design.
From the developer:
DRAINS is a Stormwater Drainage System design and analysis program. It provides a much enhanced successor to the ILSAX program which has been widely used for urban stormwater system design and analysis in Australia and New Zealand. It is co-developed by Watercom and Dr. Geoffrey O'Loughlin, developer of the ILSAX program.
You may want to check out more software, such as HY12, Evil In Sewers 2 or MB Free Biorhythm Chart Software, which might be related to Drains.