Hydraulic and process simulation software covers water-distribution, wastewater, stormwater, flood, and treatment-process modeling for utilities and civil teams.
This comparison table lets you scan verdict, composite score, price signal, agent access, and supported formats before opening the full profile.
Last updated 2026-07-19.
Free, public-domain stormwater, wastewater, and combined sewer system simulation model by the US Environmental Protection Agency -- dynamic hydrology-hydraulic-water quality simulation for single-event or continuous modeling of rainfall-runoff, pipe/channel routing, green infrastructure/LID controls, and pollutant loads; the industry-standard computational engine used worldwide for drainage design, CSO/SSO mitigation, floodplain mapping, and regulatory compliance (NPDES, CMOM, TMDL).
C1 5/5 reflects free public-domain licensing, and C2 3/5 reflects the open-source C toolkit plus community Python wrappers rather than a managed vendor API or CLI service. C4 5/5 reflects INP-native workflows with CSV and DXF export, and C5 2/5 reflects a lighter integration surface centered on ArcGIS, QGIS, PCSWMM, AutoCAD, and MicroStation.
Free tier + from $0 Agent access: API Firm fit: Solo, Small team, Growing firm
Free, public-domain water distribution system modeling software by the US Environmental Protection Agency -- performs extended-period simulation of hydraulic and water-quality behavior within pressurized pipe networks (pipes, pumps, valves, tanks), tracking flow, pressure, water age, chlorine residuals, and contaminant transport; provides a C Programmer's Toolkit (DLL with 50+ functions) for custom integration; the industry-standard computational engine underlying most commercial water-distribution modeling packages worldwide.
C1 5/5 reflects free public-domain licensing, and C2 3/5 reflects the C Programmer's Toolkit plus community Python wrappers rather than a managed vendor API or CLI service. C4 5/5 reflects INP-native workflows with CSV and DXF export, and C5 2/5 reflects a lighter integration surface centered on ArcGIS, QGIS, InfoWater Pro, and WaterGEMS.
Free tier + from $0 Agent access: API Firm fit: Solo, Small team, Growing firm
Integrated catchment modeling software for stormwater, wastewater, and flood network analysis -- 1D/2D hydraulic and hydrologic simulation, cloud or local compute, collaborative scenario management, and rule-based network design for sewer and stormwater engineers at utilities and engineering consultancies.
C1 4/5 reflects published annual pricing, C2 3/5 reflects the Ruby scripting API plus Autodesk cloud endpoints, and C5 3/5 reflects AutoCAD, Autodesk Storm and Sanitary Analysis, and Autodesk Water Infrastructure integrations. The documented file surface centers on CSV, GIS, and SWMM import for stormwater, wastewater, and flood modeling.
Free trial Agent access: API Firm fit: Growing firm
Water distribution system modeling and simulation software for hydraulic analysis, water quality modeling, fire flow analysis, energy management, and pipe network calibration -- part of Bentley's OpenFlows portfolio, serving municipal water utilities and engineering consultants.
C1 4/5 reflects published Essentials-through-Ultimate pricing, C2 3/5 reflects the WaterGEMS .NET API and iTwin Platform API, C4 2/5 reflects the proprietary WHM native format, and C5 3/5 reflects Bentley OpenFlows, iTwin, ProjectWise, and ArcGIS integrations.
subscription (Virtuosity/SELECT) or perpetual with annual maintenance Agent access: API Firm fit: Growing firm
Hydraulic transient and surge-analysis software for water distribution and wastewater piping systems. Bentley now licenses HAMMER through the OpenFlows Water family, where the current Standard, Advanced, and Ultimate tiers include the named HAMMER transient-analysis capability.
C1 3/5 reflects the $3,354 Standard tier that first includes HAMMER, C2 2/5 reflects desktop model authoring with no public standalone API, and C5 4/5 reflects OpenFlows WaterCAD, OpenFlows WaterGEMS, ArcGIS, MicroStation, AutoCAD, and ProjectWise integrations. C4 3/5 reflects INP, DGN, DXF, GIS, and CSV interoperability.
from $3,354 Agent access: API Firm fit: Growing firm
Advanced stormwater, wastewater, watershed, and water distribution modeling software by Computational Hydraulics International (CHI) -- built on the EPA SWMM5 engine with a powerful GIS interface, 1D/2D hydraulic modeling, intelligent scenario management, model calibration tools, and green infrastructure/LID design; used worldwide by engineering consultants, municipalities, and utilities for drainage design, floodplain mapping, CSO/SSO analysis, and water quality modeling.
C1 4/5 reflects published annual pricing from USD 1,600 to USD 4,400 plus a 30-day trial, and RF2 keeps C2 1/5 because no public REST API or CLI is documented for the desktop application. C4 3/5 reflects INP, SHP, CSV, DXF, and DWG workflows, and C5 2/5 reflects EPA SWMM5, EPA EPANET2, ArcGIS, and QGIS integration.
from $1,600 Agent access: API Firm fit: Small team, Growing firm
Agent-hostile
Standalone Windows stormwater hydrology and hydraulics modeler (TR-20, TR-55, SBUH; ponds, outlets, routing) in use since 1986. Licensed perpetually by node count (5-node $275 to 40-node $1,100; 20-node $825 is the most common) with an annual-license option and a free sample version. Direct CAD watershed import (v10+); desktop-only with no API.
C1 4/5 reflects published perpetual node-based pricing plus a free sample version, while C2 1/5 reflects no public API, CLI, MCP, webhook, or scripting surface. C4 3/5 reflects DWG and DXF watershed import as the documented file interface.
from $275 Agent access: API Firm fit: Solo, Small team
Water distribution system modeling and management software built on ArcGIS Pro -- provides hydraulic analysis, criticality analysis, pressure transient modeling, leakage detection, fire flow analysis, and what-if scenario simulation for water utilities and engineering firms planning, designing, and operating water distribution networks with spatial analysis and GIS integration.
RF1 keeps C1 2/5 because pricing is quote-only, and C2 2/5 reflects Ruby scripting plus Autodesk-linked simulation endpoints rather than a broadly accessible standalone API or CLI. C4 3/5 reflects GIS, SHP, and CSV workflows with INP export, and C5 3/5 reflects ArcGIS Pro, ArcGIS Online, Autodesk Water Infrastructure, and AutoCAD integration.
Quote-only Agent access: API Firm fit: Growing firm
Hidden price
Wastewater treatment plant modeling and simulation software by Hydromantis (a Hatch company) -- the first commercially released dynamic wastewater treatment plant simulator, providing a drag-and-drop interface with the industry's largest library of unit process models (Mantis2 biological model, carbon/nitrogen/phosphorous removal, sulfur/selenium, GHG carbon footprint) for designing, optimizing, and managing municipal and industrial wastewater treatment plants; includes steady-state and dynamic simulation, sensitivity analysis, process optimization, scenario management, and Python scripting (Pro+ tier).
C1 3/5 reflects published annual pricing from USD 3,700 to USD 10,400 plus a trial, and C2 2/5 reflects Python scripting plus Model-as-a-Service access only on the Pro+ tier rather than a broadly accessible API or CLI. RF2 remains attached because delivery is desktop-first, and C4 3/5 reflects CSV import and export while C5 2/5 reflects a narrow documented integration surface centered on Python.
from $3,700 Agent access: API Firm fit: Small team, Growing firm
Agent-hostile