Break up and brown the ground beef in a large soup pot over medium high heat. When just browned and no longer pink, add the water, tomato paste and taco seasoning and stir well. Bring to a boil, stir well, and lower heat. Stirring frequently, simmer for about 30 minutes, or until very thick. The goal for simmering this is to create a thick meat filling that holds together when scooped onto a bun. It should not have sauce running off it, but should still be very moist.