Short answer
A damp ring that appears around the faucet base while the water runs is a seal failure inside the faucet, not a sink or drain fault. On a deck-mounted faucet the base gasket or the spout O-rings have hardened, and both are cheap parts a plumber changes in under an hour. On a wall-mounted faucet, water showing up where the faucet meets the wall points to the seal behind the cover plate or the threaded joint inside the wall. Replace the whole faucet only when the body is corroded at the base or no parts match the brand.
Tell a base seal from a supply leak in five minutes
- Dry everything. Wipe the counter around the base, the faucet body, and the cabinet floor underneath.
- Lay a dry paper towel around the base and a second one under the sink on the cabinet floor.
- Run the faucet for 30 seconds, hot then cold, then shut it off.
- Check the top towel. Water on it with the lower towel dry puts the leak above the counter, at the base.
- Grab the spout and rock it gently side to side. Movement means the mounting nut under the counter has loosened and broken the base seal.
- Watch the base again for an hour with the faucet off and nobody using the sink.
- On a wall-mounted faucet, feel the wall just under the cover plate right after a run. Wet there and dry at the spout puts the leak at the wall joint.
If the ring only shows while water runs and the cabinet below stays dry, the base seals are the fault and the fix is a gasket, not a faucet. If water appears with the faucet off, or the cabinet floor is wet, shut both valves under the sink now and treat it as a supply leak.
Repair or replace
| Situation | What to do |
|---|---|
| Damp ring at the base, spout solid, faucet under 10 years old | Repair. New base gasket and spout O-rings. |
| Spout wobbles when you rock it | Repair. Tighten the mounting nut under the counter, then reseal the base. |
| Ring at the base and water in the cabinet below | Fix the supply side first. A wet cabinet is a hose or a valve, and it runs all day. |
| Faucet body pitted or corroded where it meets the counter | Replace. A new seal on a pitted body leaks again. |
| Brand unknown and no gasket matches | Replace. An afternoon of parts hunting costs more than the faucet. |
| Wall-mounted faucet leaking where it meets the wall | Repair, from the front. The joint behind the tile is what failed, so plan on a patch. |
What it costs
Runhome contractor estimates for a faucet leaking at its base ran from $180 to $498 as of October 2026, covering the trip, the assessment, new base seals on the faucet you have, or the work to fit a faucet you supply.
| Option | Range |
|---|---|
| Reseal the base, new gasket and hose on your faucet | $256 to $498 |
| Fit a replacement faucet you supply, seals included | $180 to $425 |
Can I do it myself?
Yes, on a deck-mounted faucet, if you have the right gasket in hand. Shut both valves under the sink, open the faucet to drain the pressure, back the mounting nut off from inside the cabinet, lift the faucet clear, fit the new gasket, and set it back down. Budget an hour and a headlamp.
Hire someone for a wall-mounted faucet, because the joint that leaks sits inside a finished wall and the tile in front of it has to come off and go back. Hire someone too if the shutoff valves under the sink will not close, since nothing gets opened up until the water stops.
What a contractor will ask you
Have these ready and you skip the back-and-forth.
- Where the water shows up: around the base on the counter, under the handle, where the faucet meets the wall, or underneath the sink.
- Whether it is a slow damp ring or water that pools and runs across the counter while the tap is on.
- When it started, in days, weeks, or longer.
- Whether the spout moves at all when you grab it and rock it side to side.
- The age of the faucet: under 5 years, 5 to 10, or older.
- Any part you already bought, with the number off the packet, and whether the gasket goes under the base or under the sink.
- A wide photo of the whole sink and faucet, plus one of the cabinet underneath.
Common questions
- Why does water pool around the faucet base only when I run the water?
The seal between the faucet and the counter has failed. Water under pressure escapes inside the faucet body and runs out at the lowest opening, which is the base. With the tap off there is no pressure at that seal, so the ring dries up.
- Can I just caulk around the base to stop it?
No, caulk traps the water instead of stopping it. The leak starts under the faucet, so a bead around the outside hides the ring while the counter keeps soaking. Caulk after the gasket is replaced, not instead of it.
- Will a leak at the base ruin the countertop?
It can, and laminate over particleboard is the top at risk. Water sits in the mounting hole and swells the core, which shows up later as a soft or raised edge around the base. Stone and quartz shrug it off, but the cabinet below still gets wet.
- I bought the gasket myself, will a plumber fit it?
Yes, most will fit a part you supply. Keep the packet so the tech can check the gasket is the base seal and not an under-sink connector. A slow damp ring with a solid spout is usually the base gasket and the supply hose together, and both are stock items on the van.
- My faucet leaks where it meets the wall, is that the same repair?
No, it is the same symptom with a different repair. A wall-mounted faucet leaks at the threaded joint or the seal behind the cover plate, and both sit inside the wall. Expect the tile or drywall in front of that joint to be opened and patched.