Start with the retaining nut, then look for other problems
Leaky, dripping exterior faucets not only waste water but also dump it next to the foundation, right where you don't want it. Luckily, they're easy to fix. If you have a frost-proof faucet like the one we show here, check out these fixes for the most common problems.
If the faucet leaks from around the handle just when the water is turned on, the stem packing may be leaking. In some cases, you can fix this by simply tightening the retaining nut that's under the handle. Remove the screw in the center of the handle and pull the handle off. Try tightening the nut slightly (Photo 1). You'll have to experiment to see which direction to turn the nut, since some faucets have reversed threads that tighten counterclockwise.
If simple tightening doesn't solve the problem, you'll have to remove the faucet stem (Photo 2) and replace the packing gasket. Turn off the water to the exterior faucet by locating the valve inside the house and closing it (or the main water valve). Buy a repair kit that matches your faucet brand and use the packing from the kit. If your faucet still leaks, the stem may be leaking and you should replace the faucet.
If your faucet leaks out of the spout when it's turned off, the washer is bad. On frost-proof faucets, the washer is located on the end of the long faucet stem. Remove the handle and nut (Photo 1) and pull the stem from the faucet (Photo 2). You may have to turn the stem to “unscrew” it before it'll come out. Getting the faucet apart is the hard part. After that, you simply replace the old parts with new ones. Pay close attention when you take the parts off (or snap a photo) so you can put the new ones back the same way. Snap off or unscrew the washer assembly and replace it (Photo 3). Then reassemble the faucet in the reverse order. If you find that the faucet starts leaking again after a short time, the valve seat is worn and you should replace the entire frostproof faucet. If the faucet is attached with threads, you can simply turn off the water, unscrew the faucet and replace it with one that's the same length. If it's soldered on, you'll have to break out your torch and soldering tools.
Most frost-proof faucets have a built-in vacuum breaker located on top of the faucet (Photo 4). If you see water dribbling out from under the cap when the water is running, it's leaking. Photos 4 and 5 show how to replace a leaking vacuum breaker. Some repair kits include the parts for this. If not, you'll have to purchase them separately.