EPANET — The Complete Guide: Free Water Distribution Network Analysis
EPANET was developed by the US Environmental Protection Agency (EPA), and it is the most widely accepted free software for analysing pressurised water distribution networks. Its engine sits at the core of quite a few commercial programs, and water utilities, consultants and researchers use it directly. Although it is American in origin, its hydraulic method is universal and suits any network.
EPANET
US Environmental Protection Agency
Water distribution network model — flows, pressures and water quality. The engine behind most commercial tools.
Get it from the vendorWhat EPANET calculates
- Hydraulics — pressure at every node and flow and velocity in every pipe, using Hazen-Williams, Darcy-Weisbach or Chezy-Manning.
- Extended period simulation — daily demand patterns, tank filling and draining, pumps switching on and off by rules.
- Components — pipes, junctions, reservoirs, tanks, pumps with curves, and several valve types (pressure reducing, check valves and more).
- Water quality — water age, chlorine decay and source tracing at every point in the network.
- Energy — electricity use and operating cost of the pumps.
How to build a model
1. Draw the network or import it — you can prepare the geometry in QGIS and export an .inp file with a suitable plugin. 2. Set node elevations and demands. 3. Set pipe diameters and roughness. 4. Add reservoirs, pumps and valves. 5. Run a steady-state analysis, then a 24-hour simulation with a demand pattern. 6. Check minimum and maximum pressures and pipe velocities.
QGIS
QGIS.org
Open-source GIS for spatial analysis, layer work and map production.
Get it from the vendorWhat's missing
The interface is old and simple, and runs on Windows only. There is no automatic pipe sizing, no water hammer (transient) analysis and no built-in calibration against measurements. There are no map backgrounds in the interface itself. All of these are available in commercial programs built on the same engine, or through open Python libraries such as WNTR.
Who it suits
Water and wastewater engineers, water utilities, designers of neighbourhood and facility networks, and civil and environmental engineering students — this is the tool in which network analysis is learned.
Companion tools
For drainage and sewers in free-surface flow — SWMM, also from EPA. For rivers and channels — HEC-RAS. For pump and pumping system calculations — Hydraulic Institute Tools.
SWMM
US Environmental Protection Agency
Urban drainage model — runoff, sewers, detention and infiltration, including runoff quality.
Get it from the vendor
HEC-RAS
US Army Corps of Engineers
1D/2D hydraulic model for rivers, bridges and culverts, with floodplain mapping. The world standard.
Get it from the vendorBottom line
EPANET is simple, proven and accurate. For most everyday water network work it is fully sufficient — and for the rest, it is the base every other tool relies on.