How to Fix a Leaky Faucet Base
Updated February 20, 2026
Fix water pooling around your faucet base -- replace worn O-rings, tighten loose mounting nuts, or reseal a cracked base plate on single-handle and two-handle faucets.
Overview
Water pooling around the base of the faucet is not the same thing as a dripping spout. A spout drip means the cartridge is worn. A base leak means water is escaping from around the faucet body itself -- worn O-rings on the spout, a loose mounting nut under the sink, or a failed seal between the base plate and the sink surface. These leaks are sneaky because the water runs down where you cannot see it, pools on the countertop, and eventually drips into the cabinet below. That means water damage, mold, and a rotting cabinet floor. The fix is usually a couple of O-rings -- under $5 in parts and 30 minutes of work.
What You'll Need
Safety First
- Shut off both hot and cold supply valves under the sink before taking the faucet apart. Open the handle to bleed off any remaining pressure.
- Cover the drain with a rag or stopper before you start. O-rings, screws, and small parts have a way of rolling straight down the drain if it is left open.
Step-by-Step Instructions
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Confirm the Leak Is at the Base (Not the Spout or Connections)
Dry the faucet and countertop completely. Lay paper towels around the base. Turn on the faucet and watch the base closely for 30 seconds. Water appearing around the base where the faucet body meets the sink? That is your base leak. Dripping from the spout when the faucet is off? That is a cartridge issue (see our cartridge guide). Dripping under the sink from supply lines? That is a connection issue. Base leaks typically only show up when the faucet is on and water is flowing through the body.
Tip: Single-handle faucet with a swivel spout? If the leak only appears when you rotate the spout to one side, the O-rings on the spout body are worn. Classic symptom -- the rotating seal has deteriorated and water escapes during movement. -
Replace the Spout O-Rings (Most Common Fix)
Rotating spout on a single-handle faucet? Worn O-rings are almost certainly the cause. Shut off the water. Pop the decorative cap off the handle, remove the screw, pull the handle off. On most faucets, the spout body now pulls straight up off the base. You will see two or three O-rings wrapped around the cylindrical body -- those are the seals that keep water from escaping the rotating joint. Cut the old ones off with a utility knife or roll them off. Bring them to the hardware store to match, or grab an O-ring assortment kit ($3-5). Coat the new O-rings with silicone plumber's grease, slide the spout back down until it seats, and reinstall the handle.
Tip: Match both the diameter and the thickness of the O-ring. Right diameter but too thin will not seal. An assortment kit ($3-5) covers most faucet sizes and you will use it again on future repairs. -
Tighten or Reseal the Mounting Nut
Faucet wobbles or feels loose on the sink? The mounting nut underneath has loosened. Reach under the sink and find the large nut (or nuts) that hold the faucet to the sink or countertop. Tighten clockwise with a basin wrench. If the nut is already snug and the base still leaks, the putty seal between the faucet base and the sink surface has failed. Disconnect supply lines, remove the mounting nuts from below, pull the faucet out, clean the sink surface, apply fresh plumber's putty under the base plate, and reinstall. Tighten until the putty squeezes out evenly and wipe the excess.
Tip: A basin wrench ($10-15) is practically essential for this job. The space under the sink is too tight for regular wrenches to reach the mounting nut at the right angle. If you do not have one, a long adjustable wrench with a pivoting head works in a pinch. -
Check the Base Plate Seal (Deck Plate Faucets)
Faucet sits on a deck plate (a large plate covering multiple sink holes)? Water can leak between the plate and the sink when the original putty or gasket seal wears out. Pull the faucet and deck plate together (disconnect supply lines, remove mounting hardware from below, lift from above). Clean all old putty or gasket material off the sink surface and the underside of the plate. Run a fresh continuous rope of plumber's putty around the entire perimeter. Set the plate back, press down firmly, reinstall the hardware, and tighten until putty squeezes out evenly. Wipe the excess.
Tip: Some deck plates come with a foam gasket instead of putty. If the foam has compressed or deteriorated, swap it for plumber's putty. Putty stays pliable indefinitely -- foam gaskets compress permanently and lose their seal over time. -
Reassemble, Test, and Verify
Reconnect supply lines and turn the water on slowly. Run the faucet while watching the base for moisture. Rotate the spout through its full range if applicable. Dry the base and countertop, lay a paper towel around the faucet, and use it normally for 30 minutes. Dry paper towel means you are good. Also check under the sink for drips from supply line connections you may have disturbed during the repair.
Tip: Still leaking after new O-rings? The faucet body itself may have a crack or corrosion point. This is rare but it happens on older faucets. A cracked body cannot be repaired -- the faucet needs to be replaced.
Pro Tips
- Single-handle kitchen faucet with a swivel spout leaking at the base? It is O-rings. Almost every time. Two O-rings, under $2, 20 minutes.
- Always grease new O-rings with silicone-based plumber's grease before installing. The grease helps them slide into position without twisting or pinching, and it extends their life by reducing friction when the spout rotates.
- Dripping from the base and the spout? Do the cartridge and the O-rings in one session. Saves you from shutting off the water and disassembling the faucet twice.
- Pull the spout body straight up with a slight twist. If it is stuck, wrap a cloth around it and use pliers. Do not pry against the sink or countertop -- you will scratch or chip the surface.
- Faucet over 15 years old and needing multiple repairs? At some point, replacing it entirely ($100-200 for a quality faucet that lasts 15-20 years) is cheaper in time and parts than keeping the old one alive.
When to Call a Pro
This is a straightforward DIY repair. Call a plumber only if the faucet body is cracked or corroded (replacement time), if you cannot reach the mounting nuts due to a tight cabinet layout, or if you are replacing the whole faucet and want help with installation.