I have a customer that has pointed out that they have a bathroom exhaust fan mounted on the ceiling in the tub area. It has a metal Pull chain.

Does this fan need relocated if i get rid of the pull chain and install a wall switch.

I don't know of a rule against a fan within a certain distance of a tub.

America- NEC- 410.10(D)

Is there a luminaire associated with this fan?
(My spell check hates Luminaire- Oh well)

If there is,this will affect your code.

No Light

I was on a job where the fan got installed above the tub (wasn't me ). Inspector didn't make us move it... and he doesn't miss much.

I wouldn't install one in a tub, but I also wouldn't relocate one out of a tub either, unless I was told to by customer or inspector.
Are you good at drywall?

I had a look through the book and came across

22-102 (4)(5) ....

So, if a bathtub area is considered a class 1 location, then any equipment installed in the tub would have to be drip proof, weatherproof, watertight. But one could argue that the fan is actually in the attic....

Fan grills are designed to minimize splashing aswell.

GFIing the circuit is a possibility too.

I don't think a bathtub is a classified area. It's probably a pool.