a 30 foot by 40 foot backyard with a pool could look like: Imagine a rectangular backyard, 30 feet wide and 40 feet long. In the center, a sleek, rectangular pool, perhaps 15 feet by 30 feet, leaving a good amount of space on all sides. Around the pool, there would be a paved patio area, perfect for lounge chairs and umbrellas. In one corner, you could envision a small outdoor dining set, and in another, a built-in fire pit with comfortable seating. See more