If you’ve ever turned on a tap and wondered how the water gets there—or why pressure drops during a fire hydrant test—you’ve brushed up against the complex world of water distribution systems. Designing and managing these hidden networks is no small feat. That’s where EPANET comes in.

Have you used EPANET on a real project? What was your biggest modeling surprise? Let me know in the comments below!

And because it’s free, the only investment is your time. Download it, model a simple loop system, and watch how pressure balances across two parallel pipes. Once you see that first color-coded pressure contour map, you’ll understand why EPANET has been quietly keeping our taps flowing for 25+ years. Download EPANET from the EPA’s official website. For tutorials, check out the free EPANET Beginner’s Guide PDF or the YouTube series by the Open Water Analytics community.