If your faucet is wet at the base of the spout or around the handle — not dripping from the tip — the most likely cause is a set of worn spout O-rings. Those are the little rubber rings that seal the swivel spout to the faucet body. Water sneaks past them and shows up at the base whenever the water is running. The fix is cheap: shut off the water, pull the spout, and slip on new O-rings with a dab of silicone faucet grease. Fifteen-dollar part, half an hour, no plumber needed.
But “leaking at the base” covers a few different failures, and the right fix depends on exactly where the water shows up and what kind of faucet you have. Below I rank the causes by how often I actually see them, then walk the repair by faucet type. If instead your faucet only drips from the spout tip when it’s shut off, that’s a different problem — see our guide on how to fix a dripping faucet.
First, pin down where the water is really coming from
This takes two minutes and saves you buying the wrong part. Dry everything with a towel. Then wrap a dry paper towel around the base of the spout and a second one around the base of the handle. Run the faucet, work the handle hot and cold, and swivel the spout. Check which towel gets wet first.
- Wet at the spout collar (where the spout swivels): worn spout O-rings. Usually only leaks while water is running.
- Wet around the handle: a bad cartridge/cartridge O-rings, or on older two-handle faucets a loose packing nut.
- Water pooling on the deck under the whole faucet: a loose mounting nut or a failed base-plate gasket underneath — often the supply line or the sink itself, not the faucet valve at all.
Ranked likely causes
| Likelihood | Cause | Where it leaks | The fix |
|---|---|---|---|
| Most common | Worn spout O-rings (swivel-spout collar) | Spout base, only when running | Replace O-rings, grease them |
| Common | Bad cartridge or worn cartridge O-rings | Around the handle, running or off | Replace the cartridge |
| Common (older faucets) | Loose or worn packing nut / stem packing | Around the handle stem | Tighten the packing nut, or re-pack |
| Occasional | Loose mounting nut or failed base gasket | Pooling on the deck under the base | Tighten mount, replace gasket/putty |
| Occasional | Loose supply-line connection | Deck or in the cabinet below | Snug the supply nut, replace washer |
| Rare | Cracked faucet body | Anywhere, gets worse fast | Replace the faucet — no reliable patch |
Note the crossover: worn rubber (O-rings, packing) accounts for the large majority of base and handle leaks. Cracked bodies are rare, and epoxy or sealant on a cracked casting only buys you a few days before it fails again.
Know which faucet you have
Before you take anything apart, identify the type — it decides the parts and the steps. If you’re new to this, our faucet repair 101 walkthrough covers teardown basics.
- Compression: two handles, each turns several rotations and gets firm at the end. Older homes. Uses a stem, packing, and a seat washer.
- Cartridge: one or two handles that move smoothly through a quarter-to-half turn. Sealed cartridge inside.
- Ball: single handle that rotates over a dome (classic Delta/Peerless kitchen style). Ball rides on spring-loaded rubber seats.
- Ceramic disc: single lever, very smooth, short throw. Two ceramic discs inside a cylinder.
Always start every repair the same way: shut off both supply valves under the sink, open the faucet to bleed pressure, and plug the drain so small screws and clips don’t vanish.
Fix it, by faucet type
Compression (two-handle, older)
A leak around the handle stem on these is almost always the packing nut or the packing under it.
- Try the easy fix first: with the handle on, snug the packing nut (the nut directly under the handle) a quarter-turn with an adjustable wrench. Test. Overtightening makes the handle stiff, so go small.
- If it still weeps, shut off the water, pull the handle, and back off the packing nut fully.
- Replace the packing: modern faucets use a rubber packing washer or O-ring; older ones use graphite-impregnated string. For string, wrap two to three turns tightly around the stem in the direction the nut tightens, so it doesn’t unravel.
- Reassemble and test. While you’re in there, if the spout base also leaks, replace the stem O-rings too.
Cartridge (single- or two-handle)
A handle-base leak here means the cartridge seals or its O-rings are shot. A spout-base leak on a single-handle model usually means the spout O-rings under the spout sleeve.
- Pop the decorative cap and remove the handle screw (often a small hex/Allen screw). Lift the handle off.
- Remove the retaining clip or retaining nut that holds the cartridge, and pull the cartridge straight up. A stuck cartridge may need a puller tool — don’t pry with a screwdriver and crack the body.
- For a spout-base leak, slide off the spout sleeve and replace the O-rings on the body; grease them with silicone faucet grease before reseating.
- Drop in a matching new cartridge (for example Moen’s 1225 for many of their single-handle kitchen faucets — confirm the model against your faucet). Line up the tabs/orientation exactly, reinstall the clip, and reassemble.
Ball (single-handle, Delta/Peerless style)
If a ball faucet leaks at the base of the handle, the cam-and-packing on top of the ball or the adjusting ring is the usual culprit; a leak that also drips from the spout points to the seats and springs.
- Loosen the setscrew, lift the handle, and use the little wrench that comes in the repair kit to loosen the adjusting ring. Unthread the cap.
- Lift out the cam, the rubber cam packing, and the ball. A worn cam packing is what leaks around the handle — replace it.
- While it’s open, pull the two rubber seats and springs from the body and drop in new ones (Delta’s RP4993 kit is the common seats-and-springs set; a full kit like RP77763 adds the ball, cam, cap and adjusting ring). Springs go in large-end-first, seats open-end-down over them.
- Reassemble, align the tab on the cam with the slot in the body, and tighten the adjusting ring just until no water leaks around the stem with the handle full-on.
Ceramic disc (single lever)
These rarely leak, but when they do at the base it’s the inlet seals under the disc cylinder or a cracked cylinder.
- Remove the handle and the cap/dome to expose the cylinder held by two or three screws.
- Lift the cylinder out and check the rubber inlet seals on its underside. Clean any mineral scale from the seats and replace the seals.
- If the ceramic cylinder is cracked or badly scaled, replace the whole cylinder — the discs aren’t serviceable separately.
Water pooling on the deck (base-plate / mounting)
If the valve is dry but water collects under the whole unit, the faucet is loose or its seal to the sink failed.
- Under the sink, tighten the mounting nut with a basin wrench so the faucet can’t rock.
- If the deck gasket or plumber’s putty has hardened, remove the faucet, scrape the old material, and reseat with a new rubber gasket or a fresh 1/4-inch rope of plumber’s putty.
- Also feel the supply-line connections — a weeping supply nut runs water down to the base and mimics a faucet leak. Snug it or replace the washer.
Tools and parts
- Adjustable wrench and a basin wrench (for the mounting nut)
- Allen/hex key set and a small flat screwdriver
- Needle-nose pliers and a cartridge puller (for stuck cartridges)
- Replacement O-ring kit sized to your faucet, or a matching cartridge / seats-and-springs kit / packing
- Silicone faucet grease (plumber’s grease) — not petroleum jelly, which degrades rubber
- New base gasket or plumber’s putty, and white vinegar to dissolve mineral scale
- Towel, flashlight, and a drain plug
DIY cost vs. calling a pro
| Repair | DIY parts cost | Typical pro cost |
|---|---|---|
| Spout / handle O-rings | $5–15 | $125–200 service call |
| Packing nut / re-pack | $3–10 | $125–200 |
| New cartridge | $15–50 | $150–275 |
| Ball seats & springs / full kit | $8–35 | $150–275 |
| Base gasket / re-mount | $5–15 | $150–250 |
| Full faucet replacement | $60–250 (faucet) | $150–350 labor + faucet |
Difficulty and time
Beginner, 30–45 minutes for O-rings, packing, or tightening a mount. Moderate, 30–60 minutes for a cartridge, ball, or disc rebuild — mostly because a corroded cartridge can fight you coming out. The single hardest part is usually removing a stuck cartridge without cracking the faucet body; go slow and use a puller rather than force.
Call a licensed plumber if…
The faucet body is cracked, the shutoff valves won’t close or themselves leak, the cartridge is seized and won’t budge with a puller, you find water damage or rot in the cabinet or subfloor below, or you’ve replaced the seals and it still leaks — that last one can point to abnormally high water pressure stressing the seals (residential should sit around 40–60 psi). If your pressure feels off in general, our guide on whole-house water pressure is a good next read.
FAQ
Why does my faucet only leak at the base when the water is running?
That’s the signature of worn spout O-rings. With the water off there’s no pressure behind them, so they hold; turn the water on and it forces past the tired rubber and out the spout collar. Replace the O-rings.
Do I need to replace the whole faucet for a base leak?
Almost never. The vast majority of base and handle leaks are a few dollars of rubber — O-rings, a cartridge, packing, or a deck gasket. Replacement is only warranted if the body is cracked or the faucet is so old that parts are unavailable.
Can I just tighten something to stop it?
Sometimes. A loose packing nut, a loose mounting nut, or a loose supply connection all respond to a careful quarter-turn. But a worn O-ring, cartridge, or seat won’t seal by tightening — that rubber has to be replaced.
What’s the difference between a base leak and a spout drip?
A base leak escapes around the outside of the faucet — the spout collar, handle, or deck. A tip drip runs out the spout outlet when the faucet is shut off and points to a bad seat, seat washer, or cartridge seal. Different symptom, sometimes different part — see our dripping faucet guide for that one.