Typically, an outdoor water spigot can last for years without servicing until it would eventually see water starting to continuously spray from its handle or drip from its spout, and you will have no choice but to repair it. For the handle, you can try tightening its packing nut with a wrench or remove its valve stem assembly if the first step fails to stop the leak. If the problem comes from the spout, you will also have to remove the valve stem assembly.
Well, this job can be easy as long as the spigot is not too corroded for you to disassemble; otherwise, it can be difficult. Basically, a spigot has a basic compression valve that tightens a washer onto its seat when you turn its handle, and leaks happen when such a washer or the packing around its handle wears out. All in all, when you are replacing either the handle or the spout, you have to remove the packing nut. Here are the steps to follow:
1. Turn off the water to the spigot, either by turning off the main water supply for your home or by turning off an inline valve that is controlling the water line to the area where the spigot is attached.
2. Unscrew the spigot’s packing nut under its handle using a wrench. If it does not turn, spray it first with a lubricant, which you might have to perform more than once after every few minutes to make it lose corrosion. Then, hold the spigot steady with a pair of adjustable pliers if you need to bear down on a problem nut that is frozen by rust and other corrosive elements.
3. Pull off the nut and the valve out of the housing of the spigot. You can do this by turning the valve over and unscrewing the washer on the end using a Phillips screwdriver. Then, with a flat-head screwdriver, pry the washer out and replace it with a new one.
4. Unscrew the valve handle and pull off the packing nut if the spigot was leaking from this component. It there is a packing washer, then replace it. If there is a packing string, then pull off the old string and wind the new one around the packing threads.
5. Push the valve back into the housing of the spigot, screw the packing nut and then tighten it with a wrench. Replace the handle and tighten the screw. Afterwards, you can turn the water on.
More Useful Tips
If your spigot has an anti-siphon valve screwed to its spout, and water is spraying from it, unscrew the component and replace it. If the problem involves only a small amount of water leaking from the handle, you might be able to fix it by tightening the packing nut with a wrench.
If you have a frost-free valve stem, then the leak can be more difficult to repair, especially if it is coming from inside the wall or if the valve stem is soldered onto the water supply line, instead of being screwed into it. If this is your case, then you can consult a plumbing supply store for advice.