I am having trouble to sign in this forum so, I joined this one tortoise forum. Thank u everyone for great advicesI recommend them having both water and UVB lighting available at all times. While they can be healthy for a time without them (maybe a week for water, a month or so for UVB), they will absolutely need them to survive in the long run. Both are essential for your turtle. Sunlight can provide UVB, but the turtle will need to spend all day outside in a deep pond with partial shade. UVB and clean, plentiful, and oxygenated water are needed for all aquatic turtles. This is what happens when a turtle gets too little UVB, whether from the sun or not. This is called Metabolic Bone Disease (MBD). Very unhealthy for the animal, as UVB is needed for shell growth and the turtle's internal functions.
That being said, I'm not a turtle expert. I highly recommend joining this forum, the folks over there will be able to help you much more. Roofed turtles are very uncommon in the U.S. (I don't believe I've ever seen one here), but I think that there are a few folks here from India who have them, as well as breeders and conservationists who know more. Hope this helps!
Turtle Forum
www.turtleforum.com