Notes

Saving projects

Every project is a tab, and every tab is saved in this browser as you work. Clearing your browser data deletes them all, so keep your work in a file: File, Save as. An asterisk on a tab means it holds changes that are not in a file. Nothing is ever written to a file unless you ask. In some browsers a project connects to the file you save it to, and File, Save writes back to that same file from then on; in others no connection is possible, so Save is disabled and only Save as is available. When a project file is kept on a shared drive, this page tells you if a colleague already has it open, so that two people do not write over each other.

Pump curve

A pump follows H = H₀ − aQ^b, where H is the head the pump adds and Q is the flow through it. Enter one, two, or three points from the manufacturer’s curve. Three points, the head at zero flow, the normal working point, and the point of highest flow, fit H₀, a and b directly, and follow a published curve most closely. Two points fit a parabola (b = 2) with its peak at zero flow. One point uses a common rule: the head at zero flow is 1.33 × the head you enter, and the highest flow is 2 × the flow you enter, which again gives b = 2. A pump with no points entered adds no head at all. The curve is not cut off where the head reaches zero, so asking a pump for more flow than its curve can deliver gives a negative head. The fix is a bigger pump or a smaller demand, not a different curve fit. A curve can hold more than three points, and every point you gave it is read.

Color band boundaries stay the same

Color band boundaries are set when you choose a data classification method. They are not set again at each time step, because that would make the colors mean something new at every step, and that is not helpful for visualizing your system. EPANET works the same way. To get new boundaries, choose a method again or enter your own boundaries.

Hazen-Williams constants match EPANET

In August 2026 the Hazen-Williams coefficient and exponent were changed to match EPANET. Head loss results differ from earlier versions of this page by up to 0.1 percent, which is far smaller than the uncertainty in the C value itself.

Which EPANET this page runs

The EPANET solver on this page is OWA-EPANET 2.3.5, released on 20 February 2025. EPANET is developed by Open Water Analytics, a community that works with the United States Environmental Protection Agency, which released version 2.2.0 in December 2019. The run report calls it 2.3.05 because the engine writes the last number in two digits. It reaches this page through epanet-js 0.9.0 by Luke Butler, under the MIT licence, and it runs inside your browser: your network is never sent anywhere to be solved.

Tables

Table columns help

Select column	Click heading
Add or extend column selection	Ctrl+click or Shift+click another heading
Move (reorder) selected column(s)	Drag or use Manage columns… in right-click or ⋮ menu
Menu ⋮ and sort arrow.	Hover a heading's top corner, or select or Tab into a heading
Hide, Show all, or Manage visibility and order	Right-click heading or ⋮ menu in heading top right corner
Sort by column	Arrow icon in heading top right corner
Paste as new rows at end of table	Right-click, ⋮ menu in heading top right corner, or Ctrl+Shift+V

Table keyboard shortcuts

Arrow keys	Navigate.
Tab, Enter	Finish entry and navigate across / down one cell.
Shift+Tab, Shift+Enter	Navigate backward.
Shift+arrow keys	Extend the selection.
Ctrl+C	Copy the selection.
Ctrl+D	Fill the selection down from its top row.
Ctrl+Enter	Fill the selection with the active cell's value.
Ctrl+A	Select the whole table.
Ctrl+Shift+V	Paste as new rows at end of table.
Ctrl+Shift+PageDown, Ctrl+Shift+PageUp	Switch to the next or previous tab, whether a table or a graph.
Delete	Clear a cell.
F2	Open a cell to edit it.
Esc	Cancel an edit.

Map

Map keyboard shortcuts

1 or Esc	Select.
2	Add a junction.
3	Add a reservoir.
4	Add a tank.
5	Add a pipe.
6	Add a pump.
7	Add a valve.
8	Add a customer.
9	Add text.
Delete	Delete the selection.
Ctrl+Z	Undo the last change.
+ or =	Zoom in.
-	Zoom out.

Menus

Menu keyboard shortcuts

Alt+Shift+letter	Open the menu with that letter, then press a row's letter to choose it. The letters show while you use the keyboard. On a Mac, use Ctrl+Option.
F10	Go to the menu bar.