The fastest, easiest way to build and use hydraulic models.
From GIS data to a running model in minutes — then calibrate, plan, and operate your water network with confidence. Powered by the EPANET engine you trust, modernised for the way you work today.
Classic EPANET is powerful — but clunky and outdated. Workarounds become your workflow — slow and cumbersome.
Big-name platforms look polished, but they're overpriced and bloated with features you don't need to analyze your network quickly.
Modern browser-based tools exist — but they force your data into the cloud, raising privacy and compliance concerns. Plus, they offer little for those doing long-term planning and analysis.
You shouldn't have to choose between speed, security, and affordability just to understand your water networks.
Work faster, with more confidence, from first model to daily use
An intuitive, modern interface that gets you to answers quickly — local-first and secure, all on top of the trusted EPANET engine.
Your data, your control
epanet-js works directly with files on your local computer and is cloud-optional. By default, your projects are run and saved locally — giving you full control, security, and privacy.
Choose the cloud only if and when you need it.
The EPANET you know, enhanced
epanet-js keeps the core functionality you're familiar with but adds a smoother, faster experience with modern touches like undo/redo, automatic elevations, quick drawing of elements, and basemaps like satellite view.
Import your network or build from scratch with intuitive tools that make it easy to update, draw, connect, and edit.
Everything you need to work quicker — without having to learn a new tool.
Built for working, not troubleshooting
Draw visually. Click to add nodes, pipes, and reservoirs — with auto-junctions and auto-elevations.
Run simulations instantly. Shift+Enter, and you're done.
See results fast. View pressures, flow paths, and velocity at a glance — all color-coded.
Make mistakes without starting over. Undo/redo is finally here!
Use satellite map overlays. Sketch and analyze your networks against a real-world layout.
EPANET file compatible. Compatible with .inp files — no conversion required.
Works on Mac, Linux and Windows. Use any modern browser. No virtual machines. No installs.
Who epanet-js is for:
Utilities & consultants Build fast, run local. Everything you need to just get the job done, none of the feature bloat.
Educators & professors Teach new modelers the concepts without fighting software. Watch students draw real networks and run sims in minutes — not hours.
Students & new engineers Focus on learning, not software quirks. Undo/redo, auto-elevation, visual overlays — built to help you learn water modeling quickly.
Model water networks instantly.
No setup or downloads — just instant access right in your browser.
EPANET was a gift to the industry — free, open-source water modeling for all. But commercial vendors built on it, locked away improvements, and left the community behind.
epanet-js is our answer: a faster, simpler, affordable water modeling tool that protects your privacy and sustains the open-source future of water modeling.
We're proud to be part of the next chapter — and we're just getting started.
When you support epanet-js, you support EPANET.
When you purchase more features in epanet-js, you're investing in the future of open-source EPANET development.
Our open-source model balances innovation and accessibility:
Anyone can build on our code. The two-year commercial-use delay gives us the incentive to keep pushing forward — and that fuels progress for everyone.
That means when you support us, you support more affordable hydraulic modeling software for the entire community.
Simple, transparent pricing for every kind of modeler.
Choose the plan that works for you
Free
For everyone.$0 /yr
Web-based EPANET model
Legacy model builder
The new Pro model builder adds pipe year & materials, projection preservation and multiple languages, with custom attributes and null values coming soon. The Legacy builder is kept for maintenance only.
The new Pro model builder adds pipe year & materials, projection preservation and multiple languages, with custom attributes and null values coming soon. The Legacy builder is kept for maintenance only.
You may not know this, but for decades, the U.S. EPA has given the water industry an extraordinary gift: the free and open-source hydraulic modeling software EPANET. Odds are, if you've used any commercial hydraulic modeling software today, it was built on the EPANET engine.
The problem is, instead of giving back to their open-source roots like other industries do, big-name software vendors took EPANET's open code, built private tools on top of the engine, and then locked those improvements behind patents and proprietary licenses.
Some vendors even pressured the EPA to focus only on the engine — discouraging any effort to improve the interface or user experience for everyone else.
Those vendors now charge you exorbitant prices to use their software while EPANET lags behind — and utilities, engineers, and educators with smaller budgets suffer.
We think this is backwards — and we're on a mission to change it. We're focused on creating a better experience for the entire hydraulic modeling community.
That's why we built epanet-js under an FSL license — because we want to give you an affordable, easy-to-use water modeling option that creates a sustainable future for open-source EPANET development.
Support EPANET by using software that supports it back.
A better future for water modeling.
Simple, quick, and useful right out of the gate — designed to open-and-go.
