Next to replacing the toilet flapper doohickey, the leaky faucet is probably the most common household plumbing repair. Kitchen and bathroom faucets come in an astonishing selection of styles and a bewildering array of valve types, but once you've gone through the repair process once (or twice), shutting down a leak with a new washer or a cartridge rebuild is actually pretty easy. That's for indoor faucets, however: those tough, utilitarian outdoor faucets (actual names, hose bibs or bibbs) are different, however. When one of them leaks, it may not be a worn-out washer: it might be the valve packing.
"The what?" you may ask.
A hose bibb consists of a simple valve, usually brass, that screws into a molded metal body. To prevent leakage around the valve stem, bibbs are designed so that soft, waterproof material seals against the stem. This is what's called valve packing. When packing wears out, which it eventually does, the bibb starts leaking at the stem. Leaky packing is different from a worn-out washer, which allows water to leak out of the spout.
"The what?" you may ask.
Valve Packing
A hose bibb consists of a simple valve, usually brass, that screws into a molded metal body. To prevent leakage around the valve stem, bibbs are designed so that soft, waterproof material seals against the stem. This is what's called valve packing. When packing wears out, which it eventually does, the bibb starts leaking at the stem. Leaky packing is different from a worn-out washer, which allows water to leak out of the spout.