Opening an existing project

You can open your existing EPANET models into epanet-js using the standard INP file format. This lets you view, edit, and run simulations right in your browser –no extra software needed.

You can access this option from the Welcome modal or from the Create new… dropdown in the main toolbar.

Click Open INP and select an .inp file.
The network loads onto the map.

Tips for a successful import

1. Nodes must have coordinates

All nodes (junctions, reservoirs, tanks) defined in your INP file must have corresponding entries in the [COORDINATES] section to be properly imported and visualized. If coordinates are missing for some nodes, you will receive a warning, and those nodes will not be included in the imported model.

2. WGS84 projection (latitude/longitude) required

epanet-js needs your network to be projected in the standard WSG 84 projection system. If that’s not the case, the application will warn you about this and won’t be able to open it.

However, you can reproject your network with one of our EPANET utilities.

How to reproject your network

3. Import issues & warnings

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We're actively developing epanet-js to enhance INP file support and add more features. You can follow progress in our changelog and roadmap.

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When you import an INP file, epanet-js checks its contents. If it finds sections that aren't supported (e.g. options that differ from the default settings or water quality) it will list them as issues.

These issues appear in a dialog after the import finishes.
They're there to help you understand which parts of your model might not be fully supported or used in epanet-js.
It's a good idea to review them so you’re aware of any differences between your original EPANET model and what’s shown in epanet-js.

When you save the model, epanet-js will ask you to save a copy so your original file stays unchanged.