Water Pressure Testing Explained
The single fastest way to confirm whether a leak exists at all, before spending time or money on anything else.
The Logic Behind a Pressure Test
A closed, leak-free plumbing system holds pressure. If you seal off a section of pipe, pressurize it, and the pressure holds steady over time, there’s no leak in that section. If the pressure drops, water is escaping somewhere within it. That’s the entire principle — simple in concept, but it requires isolating the right sections to actually pinpoint where the problem is.
In practice: a gauge goes on an outdoor hose bib while the water is still on, recording the baseline city pressure — typically somewhere around 70–90 psi. The water is then shut off at the meter, and the gauge is checked again after 15–20 minutes. Any drop confirms a leak somewhere between the meter and the point where the gauge is attached. From there, isolating specific sections — irrigation vs. house, hot vs. cold, upstairs vs. downstairs — narrows down where within that system the leak actually is.
Why This Comes Before Everything Else
Pressure testing tells us whether there’s a leak and roughly which section it’s in. It doesn’t tell us the exact spot — that’s what acoustic listening and thermal imaging are for. Doing it in this order avoids wasted time: no point running detailed detection equipment over a section of plumbing that isn’t actually where the problem is.