Download of Sewers2 2013.10.08 was on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most frequent installation filename for the program is: Sewers2.exe.
We recommend checking the downloaded files with any free antivirus. The most popular version among Sewers2 users is 2013.10.08. The actual developer of the software is BJSoftware & Rules of Thumb, inc. The software is included in Development Tools.
From the developer:
Sewers2 is a major rewrite of the old Sewers program. It uses a whole new framework for building septic systems. This tool lets you specify a primary treatment (the septic tank), a secondary treatment (the sand mound itself), disinfection (not needed), and a discharge method (the sand mound again).
You may want to check out more software, such as Evil In Sewers 2, which might be similar to Sewers2.