In a large saucepan, melt the butter over medium-high heat. Mix in the flour and cook for around 1 minutes. Pour in 1 cup of water and whisk until smooth and begins to thicken. Slowly pour in the remaining water and milk, stiring until evenly combined.
Meanwhile, cook the bacon until crispy. Crumble in a small bowl. Set aside.
Mix in the pasta, salt and garlic powder into the milk mixture, stiring occasionally until the mixture begins to simmer. Reduce heat and allow to simmer for around 9-10 minutes, or until the pasta is al-dente.
Remove from heat and mix in the cheese until melted. Fold in the bacon and serve immediately.