You will have to turn water off to the hose bib and go underneath your home and look to see what type it is. Bring two wrenches either channel locks or an adjustable wrench. You may just screw it out with one wrench and use the other wrench as a holdback so you don't twist the pipe off. Take the old one to your local hardware store to match up a new one which will run anywhere from 10.00 to 20.00 dollars. Or it may be a bifferent type where you can just screw it off right outside but make sure you check under the house first cuz other wise you could make a bigger problem.