What is the rating (volts/amps) of these circuits?

If they're 15/20A 120V I don't see anything wrong with using them for lighting as well if you aren't overloading the circuit.
There are safety concerns for light placement with regard to pools. Directly over the water for instance, you can't have a light unless it's more than 12' above the water line. That goes down to 5' once you're not directly over the water (but it is required that it be GFCI protected at that point).

Thanks for responding. Both circuits are 20 amp 120volt. The light is inside an adjacent pool house, not out side.

Whether you can legally do it depend on your local electrical code however many people do this. So long as there is a neutral available (not direct drive 220v pumps) then you have what you need. Just be sure that when you tap into it, you do so in a safe and legal fashion.

Sorry SwimingPoolSteve, but most likely that is NOT legal by anybody's electrical code. Every pool pump I've seen is at least 30A and you can't tap in a lighting outlet on that whether or not it has a neutral.

Ron, almost all pool pumps are either 15A or 20A. Seldom would you ever find a 30A pump. Actually, I am not sure if there is such as thing as a 30 amp pump draw in residential applications. Double check your pump info and I think you will see that you are mistaken about pumps being on 30A breakers.

In terms of code, it is all about how you make this connection. For example if you have a sub panel in the pool shed that runs the pump you can add a new circuit for lighting no problem at all.

Yeah most of the pool pumps I've installed have been 20 amp