Mirab is a free, cross-platform desktop application for modeling water distribution and stormwater systems. It puts several established solvers behind one interface, so you pick the engine and keep working in the same project, on the same map, with the same tools.
| Engine | Use it for | Provider |
|---|---|---|
| EPA EPANET 2.2 | Regulatory-standard pressurized network hydraulics and water quality | U.S. EPA |
| OWA EPANET 2.3 | Pressure-driven demand, FAVAD pipe leakage, PCV valves, extra units | Open Water Analytics |
| EPANET-MSX 2.0 | Multi-species reactions, on top of either EPANET engine | U.S. EPA |
| EPA SWMM 5.2 | Urban drainage, runoff, hydraulics and pollutants | U.S. EPA |
| SWMM5+ 1.0 | Finite-volume dynamic-wave routing (optional add-on) | CIMM, UT Austin |
Mirab runs on Windows, macOS and Linux. It needs no Python, no QGIS and no other software on the user's machine.
- Build and edit networks in a clean, light interface with a start page, a project tree, a searchable property editor and context menus: junctions, tanks, reservoirs, pipes, pumps and valves for EPANET; junctions, outfalls, storage, conduits, orifices, weirs, outlets, subcatchments and rain gages for SWMM.
- Edit every part of a SWMM model without the text view: pollutants and land uses with buildup and washoff, inflows, dry weather flow, RDII, groundwater, snow packs, streets and inlets in forms, and dedicated editors for LID controls (with a drawing of the layers), LID usage, transects, unit hydrographs and control rules (checked as you type). A simulation options dialog covers every SWMM and EPANET option.
- Switch engines from a drop-down. Mirab checks the project against each engine's capability manifest and tells you what will be ignored or cannot run. Data an engine does not support is greyed out in the property editor.
- Run simulations in an isolated solver process, so a solver crash can never close the application. The map, time slider and charts fill in while the engine runs, and every engine can be paused, resumed or stopped with its partial results kept.
- Work on real maps: OpenStreetMap, satellite, topographic and light basemaps or your own WMS, WMTS and tile services under the network, in any of about 1,950 coordinate systems (UTM, State Plane, national grids, or a
.prjfile). Show GeoTIFF elevation models as hillshade and set node elevations from them. - Select and trace with rectangles, polygons and queries such as
Diameter < 200 AND Pressure < 20; trace upstream and downstream (following the flows of the results), select connected parts and shortest paths, edit many elements at once, split pipes and conduits, and measure distances and areas. - Import GIS and CAD data from shapefiles, DXF drawings and CSV tables, with field mapping, endpoint snapping and reprojection.
- Explore results with map coloring, flow arrows, an animated time slider, hover read-outs and time-series charts.
- Report with network tables (sortable, with filters such as
Pressure < 20), multi-element time series, profile plots, frequency and variability plots, system flow balances, pump energy audits and the engine's status report; every report exports CSV. - Model water and wastewater together: turn the water use of an EPANET model into dry-weather sewer inflows of a SWMM model of the same area, with return factors per demand category and hourly, daily and weekend patterns, and see the water network as a layer on the sewer map.
- Calibrate against field measurements: load observed pressures, flows or depths from CSV or calibration files, see NSE, KGE, PBIAS, RMSE and R² per series with charts and 1:1 plots, and let Mirab search roughness, imperviousness or any other parameter automatically (Dynamically Dimensioned Search, runs in parallel).
- Compare alternatives with scenarios: pipe upsizing, demand growth or a larger storm are stored as changes to the base model, edited anywhere in the interface, run several at a time and compared in a report and on a difference map.
- Deliver print layouts (PDF, PNG or a printer) with legend, scale bar and north arrow, complete report documents (PDF with a table of contents, or HTML), and animated GIFs of the results.
- Edit patterns, curves and time series in tabs with live charts.
- Evaluate resilience with native implementations of the Todini index, water service availability, network topology (bridges and articulation points), pipe criticality and fire-flow capacity.
- Exchange data as GeoPackage or GeoJSON for QGIS and other GIS tools, and as WNTR JSON for the Python water community. "Open in QGIS" exports and launches QGIS in one step.
- Edit the input file directly in a syntax-highlighted text view. The
.inpfile stays the master copy, and Mirab preserves every comment and line you did not change. - Work in your language: English, Persian, Arabic, Hebrew, Spanish, Brazilian Portuguese, French, Italian, German, Simplified and Traditional Chinese, with right-to-left layouts for Persian, Arabic and Hebrew.
- Extend Mirab with C++ plugins built against Qt 6.
Installers for Windows (.exe and .zip), macOS (.dmg for Apple silicon and Intel) and Linux (.AppImage and .tar.gz) are attached to each release, with SHA-256 checksums. To confirm that a download was built by this repository's release workflow, run gh attestation verify <file> --repo ehsanMa86/Mirab with the GitHub CLI. Example models are installed with the application and are also in examples/.
SWMM5+ is an optional engine for Windows, macOS and Linux, published separately by swmm5plus-capi. Install it from Project > Simulation engines > Install SWMM5+, with mirab --install-engine swmm5plus in a deployment script, or with mirab-cli engines install <manifest.json> for offline use. See docs/engines.md.
Every capability is also available from mirab-cli, which ships next to the application:
mirab-cli engines
mirab-cli run examples/epanet/mirab-demo.inp --engine epanet-2.3-owa
mirab-cli run examples/epanet/mirab-demo.inp --engine epanet-msx-2.0-owa23 --msx examples/msx/mirab-demo.msx
mirab-cli results examples/epanet/mirab-demo.anr --table node --variable Pressure --element J5
mirab-cli batch examples/epanet/mirab-demo.inp --all --jobs 4
mirab-cli resilience fireflow examples/epanet/mirab-demo.inp --flow 30 --residual 14
mirab-cli export gpkg examples/swmm/mirab-urban.inp --out urban.gpkg --crs EPSG:32614
mirab-cli model set examples/epanet/mirab-demo.inp --id J1 --column Elevation --value 21 --out j1.inp
Run mirab-cli --help for the full list. Every command has a --json form, described in docs/cli.md.
The mirab Python package in integrations/python scripts Mirab through mirab-cli: open a model, read and change element values, run simulations with live results, read result files into NumPy or pandas and run many variants in parallel. The desktop application itself does not need Python. See docs/python.md.
You need CMake 3.21 or newer, a C++17 compiler and Qt 6.5 or newer. The engines are downloaded at pinned versions during the first configure.
cmake --preset release
cmake --build --preset release
ctest --preset release
cmake --build --preset release --target package
Use the headless preset to build the command-line tool and libraries without Qt. Platform notes are in docs/building.md.
The documentation is also published as a website: https://ehsanma86.github.io/Mirab/.
- User guide
- Engines and compatibility
- Resilience tools
- Architecture
- File formats and the solver protocol
- Command line and JSON output
- Python scripting
- Building and packaging
- Writing plugins
Report problems and suggest features in Issues. Code contributions are welcome as pull requests; CONTRIBUTING.md explains how to build, test and submit them. Report security problems privately as described in SECURITY.md. Thanks to Robert Dickinson for the review of the engine integration behind release 0.2.5; everyone who helped is named in AUTHORS.
Each release from 0.2.6 on is archived on Zenodo. Cite the version you used, or all versions with 10.5281/zenodo.23679047; GitHub's Cite this repository button gives the reference from CITATION.cff. Please also cite the simulation engines your results come from.
Mirab is free software, licensed under the GNU General Public License, version 3 or later. Copyright (C) 2026 Ehsan Madadi.
The simulation engines keep their own licenses and copyright notices; see THIRD_PARTY_NOTICES.md. Mirab is not affiliated with or endorsed by the U.S. EPA, Open Water Analytics or CIMM.