Well, it just depends on how hot, and how dry. An inch of water a week is usually adequate for nearly any lawn. If your climate is humid and/or you live somewhere that gets some summer rain, then you may not need to water that much.
There are a lot of factors involved, but the bottom line is that you just need to give it as much water as it needs to stay green. If you water once a week and the grass is turning brown, then water twice a week. Or water twice as long. If the grass is really lush and you have soggy spots in the lawn, then you might be able to cut back on water. If you're really interested in how much water you're applying, place a small pan or can on the lawn when you water and see how much water accumulates during watering. Truth is, though, you can pretty easily adjust your watering by trial and error so that you give the lawn just enough to stay green. If the weather is unusually hot and dry, you'll have to increase watering. If it's cool and rainy, you can cut back.
For feeding, bermuda typically needs fertilizing when it starts to green up in spring, and another one or two feedings during the growing season. Depending on where you live and how long the growing season is, that might mean feeding in april/june/August. Be sure to use a turf fertilizer, not a general purpose fertilizer.