Question
How soon should I report a burst pipe?
Report a burst pipe as soon as you know about it. The conditions ask for a report without delay, and in practice that means the same week rather than the same hour.
With a burst pipe the useful photograph is the one taken before the water is cleared, and the useful note is the time the water was shut off.
An emergency plumber writes an invoice saying what failed and where. That invoice does more work than any description written afterwards.