On low-slope asphalt roofs, ponding water allows the oil solvent components of the asphalt to leach out and evaporate, leaving the roof membrane brittle and susceptible to cracking and leaking in the ponding location.
[5] When a scupper or drain is clogged or fails for other reasons, storm water tends to pool around that low area.
For roofs with a slope less than 1/4 inch per foot [1.19 degrees (0.0208 rad)], the design calculations shall include verification of adequate stiffness to preclude progressive deflection in accordance with Section 8.4 of ASCE 7.
[10] A municipality in New Zealand has noted that "groundwater ponding is a chronic problem, that results in damp housing and waterlogged sections.
[11] Ponding that forms on paved surfaces, like streets or parking lots that are not properly pitched, will cause issues such as deep puddles and crocodile cracking.