A dripping faucet is like a tiny metronome of wasted money. One drip per second adds up to five gallons a day — over three thousand gallons a year. That is not a drip. That is a small pond.

I put off fixing my bathroom faucet for months because I was intimidated. When I finally opened it up, I realized it was one screw, one cartridge, and ten minutes of work. Here is how to do it, whether you have a compression faucet (the old kind with two handles) or a cartridge faucet (the modern single-handle kind).

First: Figure Out What You Have

Look under your sink. There should be shutoff valves on the hot and cold water lines. Turn both clockwise until they stop. Then turn on the faucet to confirm the water is off.

Now close the drain stopper or put a rag in the drain. You will drop a screw. Everyone drops a screw.

Compression Faucet (Two Handles)

1. Pry off the decorative cap on top of the handle (the “H” or “C” indicator). There is a screw underneath.
2. Unscrew and pull the handle off.
3. Use an adjustable wrench to unscrew the packing nut. The valve stem will come out.
4. At the bottom of the stem, there is a rubber washer held by a brass screw. This is the culprit 90% of the time. Replace it.
5. Optional but smart: replace the O-ring around the stem too. They dry out and crack over time.
6. Reassemble in reverse order. Do not overtighten — snug is enough.

Cartridge Faucet (Single Handle)

1. Locate the set screw — usually under the handle, sometimes hidden behind a small plug or under a cap.
2. Loosen the set screw with an Allen wrench and pull the handle off.
3. Unscrew the retaining nut (you may need pliers).
4. Pull the cartridge straight out. If it is stuck — and old cartridges often are — there is a cartridge-pulling tool for about ten dollars. Worth it. Do not yank with pliers or you will break the cartridge inside the faucet body and then you will need a plumber.
5. Take the old cartridge to the hardware store. Buy the exact match. There are about a thousand different cartridge shapes and sizes.
6. Insert the new cartridge, aligning any tabs with the slots in the faucet body. Reassemble.

Turn the water back on slowly and test. No drip? You just saved yourself a $150 plumber visit and about 3,000 gallons of water a year. That is a good trade for ten minutes.