What is ponding water?

Ponding water refers to water that collects and sits on a flat roof surface for more than 48 hours without draining. This standing water pools in low spots or depressed areas across the roof plane, either because the roof lacks sufficient slope to shed water or because gutters, drains, and scuppers are clogged or blocked.

Ponding signals a drainage problem that demands attention. Water that remains stagnant gradually deteriorates roofing materials, especially membrane surfaces common on commercial buildings. The weight of accumulated water stresses the structure itself, and prolonged moisture exposure accelerates deterioration of insulation, decking, and fasteners. In winter conditions, ponded water freezes and thaws repeatedly, creating additional pressure on the roof assembly.

For property owners in Connecticut, ponding water also creates liability and operational concerns. Stagnant water attracts mosquitoes and debris accumulates, compromising the roof's integrity over time. Contractors specializing in flat roofing and commercial roof systems can diagnose ponding by inspecting slope, drain placement, and blockages, then recommend solutions such as re-sloping, drain relocation, or installing additional drainage capacity to ensure water runs off within the 48-hour window.