Preheat oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish.
In a large skillet over medium heat, cook the ground beef until browned. Drain excess fat.
Add taco seasoning and water to the beef, stir well, and simmer for 5 minutes.
Stir in refried beans and salsa until well combined, then remove from heat.
Place 2 tortillas at the bottom of the baking dish. Spread 1/3 of the beef mixture over tortillas, then sprinkle with 1/3 of the cheese.
Repeat layers two more times, finishing with cheese on top.
Bake uncovered for 25-30 minutes, until cheese is melted and bubbly.
Let sit for 5 minutes before slicing. Serve with sour cream and toppings if desired.