Ponding water on flat roofs — how long is too long?

Water that is still standing on a flat roof well after the rain ends points at failed drainage, and it telegraphs into ceiling stains two floors down. Inspectors read the stains inside units and trace them up. What is your roof inspection rhythm, and who on your team is allowed to say a roof is done?

A flat roof tells the truth about a building two days after the rain: the birdbaths mark every low spot, and the ceiling stains below mark the ones that have been leaking quietly for a season. The rhythm that works is boring — a roof walk on a schedule, drains cleared before they are a story, and one named person who can declare a roof work complete. How long does water stand on your flat roofs after rain — and who on your team has the final say that a roof is 'done'?