Building surveyor, when is cause of action?

[Jasonands]

My building surveyor provided a negliglent certificate, several months later I realized this as leakage began.

In the context of statue of limitations, is the cause of action the date the surveyors certificate was provided, or when I knew a claim could be brought (only when the leakage began I knew that the surveyor certificate was negliglent, before this I would not have known)

Thanks in advance