Place 1 lb lean ground beef into a large deep skillet or saucepan.
Add enough water to the pan to just cover the meat.
Turn the heat to medium and break the meat apart with a wooden spoon so it is in small crumbles.
Bring the pot slowly to a gentle boil, stirring often to keep the meat separated.
Lower the heat to a simmer, cover, and cook until the meat is fully browned and cooked through, about 15–20 minutes.
Drain the cooked meat in a colander to remove excess liquid.
Return the drained meat to the pan and stir in 1 oz taco seasoning, if using; heat briefly to combine.