March 06, 2026
When water pools around the base of your faucet every time you turn on the tap, you're dealing with one of the most common and fixable faucet problems homeowners face. This specific leak pattern, water appearing only when the faucet runs, not when it's off, points to a seal or connection failure between the faucet body and sink surface, not the spout or handle valves.
After repairing thousands of faucet leaks since 1923, our licensed plumbers have identified four primary causes. Left unaddressed, base leaks can cause hidden damage to cabinets, countertops, and subflooring, which can be costly to repair. Here's how to diagnose each cause and what it takes to fix it.
4 Causes of Faucet Leaking from Base
1. Worn or Damaged O-Rings (Most Common)
Why does this cause base leaks: O-rings seal connections between faucet components, where the spout base meets the faucet body, where cartridge stems seal against valve housings, and where supply lines connect internally. Constant exposure to water pressure, temperature changes, and mineral deposits causes them to harden, crack, or flatten over time (typically 5-10 years). When they fail, pressurized water bypasses the seal and escapes at the base.
How to identify this cause: Water leaks from the base only when the faucet runs. The leak worsens at higher flow rates. The spout spins or wiggles easily. The faucet is 5+ years old, and O-rings have never been replaced.
What to do: O-ring replacement requires disassembling the faucet body, removing the old rings, and installing new ones with plumber's grease to ensure a proper seal. Contact our licensed plumbers for professional O-ring replacement and faucet seal service.
2. Loose Faucet Mounting Hardware
Why does this cause base leaks? Mounting nuts under the sink secure the faucet to the sink deck. Daily handle operation, water pressure vibration, and thermal expansion gradually loosen these nuts over time. When the faucet lifts even slightly from the sink surface, the base gasket or plumber's putty seal breaks, allowing water to leak around the perimeter.
How to identify this cause: The faucet feels loose or wobbly when pushed side to side. Water leaks from all around the base perimeter, not from a single spot. The leak developed gradually over weeks or months.
What to do: Tightening the mounting nuts under the sink resolves this in many cases. If leaking persists after tightening, the base gasket or plumber's putty has likely failed. For cramped or inaccessible cabinet spaces, our plumbers have the specialized tools to reach and tighten the hardware properly.
3. Failed Base Gasket or Dried Plumber's Putty
Why this causes base leaks: The seal between your faucet base and sink relies on either a rubber gasket or plumber's putty, both of which are applied during installation. Over time, typically 8-15 years, gaskets harden and lose elasticity, while putty dries out and cracks, breaking the seal and allowing water to accumulate under the faucet base.
How to identify this cause: Mounting nuts are tight, and the faucet doesn't move, but water still leaks around the entire base perimeter. The faucet is 10+ years old and appears to have its original sealing material. Dried, cracked putty may be visible around the base edge.
What to do: Fixing this requires removing the entire faucet, cleaning both mating surfaces, and resealing with fresh putty or a new gasket before reinstalling. Our faucet repair specialists can remove, reseal, and reinstall your faucet, along with updating the supply lines if needed.
4. Cracked Faucet Body or Base (Rare)
Why does this cause base leaks? Physical damage from impact, overtightening during installation, or thermal shock can create hairline cracks in the faucet housing. Water under residential line pressure forces through these cracks during operation, leaking at the base where stress concentrates around mounting points.
How to identify this cause: Visible cracks in the faucet body or base (inspect closely under good light). Water leaks from the same specific spot every time. The faucet was recently struck or subjected to extreme temperature changes.
What to do: Cracked faucet bodies cannot be reliably repaired, sealants and epoxy fail quickly under water pressure. Full replacement is the only lasting fix. Our licensed plumbers can replace your faucet and help you select a properly sized replacement that matches your sink configuration.
Preventing Future Faucet Base Leaks
Check mounting nuts annually; a quick tighten prevents the most common cause of base leaks. Replace O-rings proactively every 7-10 years. When replacement is necessary, invest in a quality faucet with a brass body and ceramic disc cartridge; they last significantly longer than budget models. And address leaks promptly, even slow drips cause hidden cabinet and countertop damage over time.
The Bottom Line
Four causes account for virtually all faucet base leaks: worn O-rings (most common), loose mounting hardware, failed base gasket or dried putty, and cracked faucet body (rare, requires replacement). Start by checking whether the mounting nuts under the sink need tightening; it's a five-minute check that costs nothing. If the faucet is already tight, you're likely dealing with an O-ring or seal failure that requires disassembly and part replacement.
Faucet still leaking from the base? Contact our licensed plumbers for professional diagnosis and repair in Cumming, Alpharetta, Roswell, and North Metro Atlanta. Most leaks are diagnosed and repaired in a single service call.
