For sink sprayer leaks, turn the water on and pull out the sprayer. make sure the slide nut is screwed on tightly. Test the sprayer to test for leaks. If there are no leaks, remove the spray head and the slide nut. Turn the faucet on again and check for a leak around the crimp sleeve. If that is where the leak is, you'll need to replace both the hose and the head. If not, just replace the head.