Mark Ode, NEC/UL expert, wrote an article in Electrical Contractor Magazine, "In the Drink
The article states that when the 2014 NEC goes into effect, there will be no minimum distance for installing low voltage lighting near pools (as long as all components have the proper listings).
From the article,
The proposed new 680.22(B)(6) states: “Low-Voltage Luminaires. Listed low-voltage luminaires not requiring grounding, not exceeding the low-*voltage contact limit, and supplied by listed transformers or power supplies that comply with 680.23(A)(2) are permitted to be located less than 1.5 m (5 ft) from the inside walls of the pool.”