Roof Water Testing (Hose Test)

Sometimes a leak only shows up under specific conditions — heavy rain, wind-driven rain from a certain direction, or water pooling at a particular spot. A hose test recreates those conditions in a controlled way: we run water over a specific, isolated section of the roof — usually starting at the lowest point and working upward — while someone checks the interior for signs of intrusion.

This method is especially useful for confirming a suspected leak point before cutting into the roof, and for ruling out sections that looked suspicious but turn out to be sound. It’s slower than scanning or infrared, but it gives a direct, visible confirmation rather than an inference from a meter reading.

We use a hose test selectively — usually after scanning or infrared has narrowed down the likely area — rather than as a first step, since testing the entire roof section by section can take significant time.

How We Keep a Hose Test Controlled and Safe

A hose test isn’t just spraying water around and seeing what happens — done properly, it’s a controlled, methodical process. We isolate a specific, limited section of the roof, run water at a modest, realistic flow rate (not a high-pressure blast that could force water somewhere it wouldn’t naturally go), and have someone monitoring the interior the entire time. If no intrusion appears after a reasonable test period, we move to the next suspected section.

This controlled approach is what distinguishes a proper hose test from just hosing down the whole roof and hoping to see something — the latter can actually make diagnosis harder by introducing water in ways that don’t reflect how rain naturally behaves on that roof.