Liquids is a continuation of the EPANET and EPASWMM projects developed by Lew Rossman of the USEPA.

This software is made available to everyone under the terms of the GNU General Public License v3.0. A commercial license is also available. Companies with annual revenues below US$100k may apply for a free commercial license. Companies with higher annual revenues must contact us for a paid commercial license, or use Liquids under the terms of the GPLv3.0.

Any contributions, bug reports, patches, feature suggestions, etc you make to Liquids are made under the following terms:

• You grant me perpetual, worldwide, non-exclusive, cost-free and irrevocable copyright and patent license to use, relicense, build on and distribute your contribution.
• You represent that you are legally entitled to grant such copyright and patent license.