Comparison
How AquaSWMM compares
AquaSWMM is a desktop editor for EPA SWMM 5 models. It runs EPA’s own engine and adds 2D overland flow and storm-sewer design. This page sets it beside the programs engineers most often ask about: EPA SWMM 5 itself, PCSWMM, XPSWMM and StormWise. It covers where they are the same, where AquaSWMM is different, and where the others are ahead.
AquaSWMM is described as of release 0.12.6. Facts about the other programs are from the sources linked below, as of October 2026. Check current terms with each vendor.
| AquaSWMM | EPA SWMM 5 | PCSWMM | XPSWMM | StormWise | |
|---|---|---|---|---|---|
| Maker | HydroComplete LLC | U.S. EPA | CHI | Autodesk | Streamline Technologies |
| 1D engine | EPA SWMM 5, run unmodified | EPA SWMM 5 | Its own build of SWMM 5 | Based on SWMM, with proprietary enhancements | Its own (formerly ICPR4) |
| Model file | EPA .inp, kept byte for byte | .inp | .inp, plus a project database | Its own; exports to SWMM 5 | Its own |
| 2D overland flow | DEM grid solver coupled to EPA’s engine | None | Professional 2D: a network of junctions and conduits | Through TUFLOW | Expert: finite volume, flexible mesh |
| 2D groundwater | No; SWMM’s lumped groundwater | No; lumped groundwater | Not stated | Not stated | Expert: finite element |
| FEMA hydraulic model list | Not listed; its 1D results are EPA SWMM 5’s, which is | 1D national; 2D local | Not listed by name | 1D and 2D national | 1D national; 2D local |
| Price per seat per year | $490 | Free | $1,600; $2,400 with 2D | $7,500 (one agency’s 2024 figure) | $1,800 Pro; $3,600 Expert |
| Runs on | Windows, macOS, Linux | Windows (EPA’s program) | Not covered here; check with the vendor | ||
Sources: PCSWMM pricing; PCSWMM 2D from Abdelrahman et al., JWMM 26: C454 (2018); XPSWMM from Innovyze’s documentation and a Bassett Creek WMC planning table (see the XPSWMM guide); StormWise product page; FEMA’s list of hydraulic models. FEMA lists StormWise’s 2D for Florida and parts of South Carolina, Texas and Indiana, and SWMM 5’s 2D for local use.
Where they are the same
- Four of the five speak SWMM. EPA SWMM 5, PCSWMM and AquaSWMM all work on a SWMM 5
.inp, and XPSWMM can export one. A SWMM 5 model moves between EPA SWMM, PCSWMM and AquaSWMM without conversion. StormWise is the exception: it has its own engine and file. - The 1D hydraulics are the same equations. In AquaSWMM, EPA SWMM and PCSWMM the network is routed by SWMM 5’s dynamic wave, with SWMM’s Horton, Green–Ampt and Curve Number infiltration. The same model gives the same answer to within floating-point order.
- The commercial programs all couple the pipes to the ground. PCSWMM, XPSWMM, StormWise and AquaSWMM all send water that leaves the network over a 2D surface and back. EPA SWMM 5 does not model a 2D surface.
Where AquaSWMM is different
- The numbers are EPA’s. AquaSWMM contains no SWMM solver of its own. It runs EPA’s
runswmmunmodified and stamps every run with the engine version and the SHA-256 of the executable. A reviewer can rerun the model in the free EPA program and get the same results. - The file stays EPA’s. Every comment, blank line and unknown section survives a save byte for byte. The 2D settings live in a separate file beside the model, so the
.inpstill opens in EPA’s program and in PCSWMM. - Storm-sewer design on the same model. Rational method, Manning, standard-step HGL, HEC-22 access-hole losses and inlets, and catalog sizing on the model’s own conduits, with a submittal-shaped PDF and LandXML that Civil 3D imports as a pipe network.
- Storm Replay. From a latitude, a longitude and two dates, AquaSWMM downloads the terrain from USGS 3DEP and the hourly rain NOAA measured (MRMS), and runs that storm over the ground on a 2D grid. It is rain on terrain only: no pipes or inlets, so depths are an upper bound where a drainage system was working. New in 0.12.6 for Windows.
- Python, free. A Python terminal beside the model, and the engine as a free Python library (
pip install aquaswmm). - Windows, macOS and Linux, for $490 a seat per year, or $1,200 a year for five seats.
- Published checks. The 2D solver is tested against analytic solutions and the UK Environment Agency’s 2D benchmarks, and the results are on the validation page.
Where the others are ahead
- Acceptance and track record. XPSWMM’s 2D is on FEMA’s national list and StormWise’s is accepted in Florida and several other places. AquaSWMM’s own 2D solver is on no list, and it has been checked against benchmarks, not yet against a measured real-world flood. Each of the others has many years of projects behind it; AquaSWMM is new.
- StormWise’s 2D and groundwater. It has a flexible mesh, 2D groundwater by finite elements with seepage and leakage, and continuous simulation with soil moisture. AquaSWMM’s 2D surface is a rectangular grid with refinement round structures, and its groundwater is SWMM’s lumped store. For a job that turns on groundwater or on the Florida acceptance, StormWise is the stronger tool.
- XPSWMM’s 2D runs on TUFLOW, a long-established 2D engine.
- PCSWMM is an established product with a large user community, training and its own GIS and project tools. If a firm’s projects already live in it, there is no need to move them. Open the
.inpin AquaSWMM alongside it. - A larger company behind them. HydroComplete is small, and AquaSWMM’s installers are not yet code-signed.
Choosing
- EPA SWMM 5 if you only need the engine and the free program’s editor is enough.
- AquaSWMM if the reviewer wants SWMM and you want 2D, pipe design and a reproducible run in one program at a small-firm price. The 30-day trial is the full app.
- Moving a model? See Moving from PCSWMM and Moving from XPSWMM.
Spotted something out of date about another product? Email michael@hydrocomplete.com and I’ll correct it.
PCSWMM is a trademark of Computational Hydraulics International (CHI). XPSWMM, XPSTORM and InfoWorks ICM are trademarks of Autodesk, Inc. TUFLOW is a trademark of BMT. StormWise is a product of Streamline Technologies. AquaSWMM is independent software from HydroComplete LLC and is not affiliated with or endorsed by any of these companies or by the U.S. EPA. FEMA’s lists are FEMA’s; inclusion there is not an endorsement by FEMA of any product.