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A dripping faucet typically means a worn washer, O-ring, or cartridge inside the handle mechanism — not a broken pipe. The repair requires shutting off the local supply valve, disassembling the handle with a screwdriver or Allen wrench, replacing the worn part (available at hardware stores for under $5), and reassembling. A faucet dripping once per second wastes roughly 3,000 gallons of water per year.
Photograph each disassembly step on your phone so you know how to put it back together. Bring the old washer or cartridge to the hardware store to match the replacement exactly.
From your plumbing basics, you know that household water systems operate under continuous pressure — the municipal supply pushes water toward your fixtures at all times, and faucets are simply valves that control whether that pressurized water flows out or not. A dripping faucet means the valve is no longer sealing completely when closed. The drip is pressurized water finding its way past a worn seal, not water that somehow "got in" — it was always there, waiting. This framing immediately tells you where to look: the sealing components inside the valve mechanism.
The three common faucet types differ in how they create that seal. A compression faucet — found in older homes — uses a rubber washer on a threaded stem that physically compresses against a seat to stop flow. When you close the handle, you're literally screwing the washer down. When the washer wears out, it no longer seals. The repair is simple: unscrew the stem, pop off the old washer, replace it with one of the same size, and reassemble. Cartridge faucets (common in modern single-handle kitchen and bathroom faucets) use a removable plastic or brass cartridge containing internal seals. The entire cartridge is replaced as a unit — you pull out the old one and insert a matching replacement. Ball faucets use a rotating ball with spring-loaded rubber seats and O-rings; they have more parts and are correspondingly more complex but still DIY-repairable.
The universal first step — regardless of faucet type — is shutting off the local supply valve: the oval handle beneath the sink (or behind the toilet, for toilet faucets). Turn it clockwise until it stops, then open the faucet to release pressure and verify the water is actually off. This is a non-negotiable step. Skipping it and proceeding with disassembly will result in a minor plumbing problem becoming a minor flood. Once the supply is off, you can work as slowly as you need to without pressure — literally.
Your basic hand tools — screwdriver, Allen wrench, and adjustable pliers — handle most faucet repairs. The practical technique that prevents confusion during reassembly is to photograph each step as you disassemble, in sequence on your phone. Faucets have surprisingly few parts, but their specific arrangement matters for the valve to seal properly on reassembly. Bring the removed washer or cartridge to the hardware store in a small bag — matching it physically is far more reliable than matching by memory or model number alone. The parts cost under $5-15 and take minutes to install. Most people who pay a plumber $150 to fix a dripping faucet are paying for not knowing it was a $5 part and a 30-minute job.