1) Fiberglass tubs are notorious for getting hairline cracks that usually open up when someone is standing in it with the water running.
2) Also it might be a leak from upstream (plumbing behind the w ... read more
ConsultĀ a professional.
Whether it's 12" or 12' off the ground there are too many safety and code issues for the average homeowner to tackle. Better to do it right than to regret it later.