The pool's tiles were "pretty well shot", he said.
A report is being prepared on the state of the pool and the estimated cost of upgrading it, but Mr Taylor said it was not possible to confirm costs for all the work required as there were various options that needed to be investigated fully.
However, when asked if the options might run to hundreds of thousands of dollars, he said that was potentially the case.
The pool, in Castle St, Dunedin, commonly known as the physio pool, is maintained by the board but operated by the Otago Therapeutic Pool Trust.
Annual maintenance over the Christmas period cost $25,591, similar to previous years, but there has been concern for at least a year that the pool has reached the stage where it will need significant work to retain an acceptable level of safety.
Among the options being considered were making the pool shallower at the deep end, dropping the 35deg C temperature and changing the ventilation system to reduce the effect of the steam.
It was clear when the pool was drained over the Christmas break that the deterioration had got steadily worse, he said.
There are about 50,000 visits to the pool each year by patients and members of the public.
