HEC-WAT has been developed for use by the U.S. Army Corps of Engineers (USACE) in their specific needs regarding watershed planning studies. Software developed at the Hydrologic Engineering Center (HEC) is made available to the public whenever appropriate. Use of HEC-WAT is not restricted, and individuals outside of USACE may use the software without charge, however HEC cannot provide user assistance or support for this software to non-USACE users. Downloading this software indicates full acceptance of the user's responsibility in the use of this software. Please see the distribution policy for more details.
HEC-WAT 1.1 (April 2026):
Download HEC-WAT 1.1 (portable package for Windows (1.1 GB) Release Notes.
The HEC-WAT 1.1 has been tested with HEC-HMS 4.13, HEC-ResSim 3.5.1, HEC-RAS 6.5, and HEC-FIA 3.3, however it is possible for the user to update individual programs to the necessary version for their project.
Please see the Documentation page for the latest HEC-WAT user manuals, guides, example data, release notes and technical documentation.
Legacy Version (HEC-WAT 1.0):
We strongly recommend users upgrade to the current release version of HEC-WAT 1.1 as we cannot provide any support for HEC-WAT 1.0.
The install package includes HEC-WAT Version 1.0; HEC-HMS (4.2.1), HEC-ResSim (3.3), HEC-FIA (Version 3.0.1), and HEC-SSP (2.2.1).
Download HEC-WAT 1.0 (portable package) for Windows (788 MB)