Do red eared sliders need a dry area?

Yes, red-eared sliders need a dry area to get out of the water. Above this area should be a turtle basking lamp. Aquatic turtles will bask daily. Basking keeps the turtle's skin and shell health from fungus while the UV in the light is needed for the turtles growth. Without a dry area and a basking light your turtle will not be healthy and happy.