A bathroom faucet that drips through the night, barely delivers water, or leaves a puddle under the sink is more than an annoyance. It can waste water, damage a vanity, and turn a small repair into a larger plumbing bill. This guide to bathroom faucet repair helps you identify the most common problems, decide what you can safely handle, and recognize when it is time for professional help.
Start by identifying where the water is coming from
The location of the leak usually points to the failed part. Before taking anything apart, dry the faucet and the area beneath it with a towel. Run both hot and cold water, then watch closely for a few minutes.
Water dripping from the spout after the handles are turned off often means an internal washer, cartridge, seal, or valve seat is worn. A leak around the base of the faucet may come from damaged O-rings, a loose mounting nut, or a failing gasket. Water appearing inside the vanity is frequently caused by loose supply connections, cracked supply lines, or a leaking drain assembly rather than the faucet itself.
If water is collecting near an electrical outlet, soaking the cabinet floor, or continuing to leak after you shut off the faucet handles, shut off the water supply valves under the sink. If those valves do not work, use the home’s main water shutoff and arrange for service promptly.
Gather the right tools before you begin
Most basic bathroom faucet repairs do not require a large tool collection. Have a towel, small bucket, adjustable wrench, screwdriver set, Allen wrench set, slip-joint pliers, and plumber’s grease available. A flashlight is useful in tight vanity cabinets.
Put the drain stopper down or cover the drain opening with a rag before removing any small screws or clips. Faucet parts are easy to lose, and one dropped retaining clip can quickly stop a simple repair.
The replacement part matters as much as the repair itself. Take the old cartridge, stem, washer, or O-ring to a plumbing supply store when possible. Faucets can look similar on the outside while using very different internal parts. Installing a nearly correct part often creates another leak or causes the handle to bind.
Guide to bathroom faucet repair: fix a dripping spout
A dripping spout is the most common faucet complaint. The repair depends on the faucet design. Most bathroom faucets use either a compression stem, a cartridge, a ball assembly, or ceramic discs. Single-handle faucets commonly use cartridges or ball assemblies, while two-handle faucets may use cartridges or compression stems.
Start by turning off the hot and cold shutoff valves under the sink. Open the faucet to release remaining pressure. Plug the drain, then remove the handle. Some handles have a visible screw, while others hide it beneath a decorative cap.
Once the handle is off, remove the retaining nut or clip that holds the cartridge or stem in place. Pull the part straight out if possible. If it is stuck, avoid forcing it with excessive pressure. A seized cartridge can crack the faucet body, especially on older fixtures. A cartridge puller or professional service may be the safer choice.
Inspect the removed part for cracked rubber, worn seals, corrosion, or mineral buildup. Replace the cartridge or damaged washers and O-rings with matching parts. Apply a light coating of plumber’s grease to rubber seals before reassembly. Do not use petroleum-based grease, which can damage certain rubber components.
Reassemble the faucet in the reverse order, turn the water valves back on slowly, and test the faucet. Check both water temperatures and watch for drips from the spout and leaks around the handle.
Solve weak water flow without replacing the faucet
Low flow from a bathroom faucet is often caused by mineral buildup in the aerator, the small screen at the tip of the spout. This is especially common in areas with hard water. A clogged aerator can make the faucet feel weak even when water pressure is normal everywhere else in the home.
Unscrew the aerator by hand or use pliers with a cloth around the metal to prevent scratches. Take apart the screen and internal pieces in the order they come out. Rinse away loose debris, then soak mineral-coated pieces in vinegar for several hours. Use an old toothbrush to remove remaining buildup, rinse thoroughly, and reinstall.
If cleaning the aerator does not improve flow, compare the hot and cold sides. Low flow on only one side can point to a clogged supply valve, blocked cartridge, or issue with that water line. Low pressure at multiple fixtures may be a larger plumbing issue, not a faucet repair.
Stop a leak at the faucet base or under the sink
Water around the faucet base does not always mean the faucet itself has failed. First, run water directly into the sink without splashing the faucet base. If no water appears, the leak may simply be caused by water getting behind the fixture during normal use. A worn caulk line can allow that water into the cabinet below.
If water appears around the base while the faucet is running, worn spout O-rings or internal seals may be the problem. On many models, the spout can be lifted off after the handle and retaining hardware are removed. Replace the O-rings and lubricate them lightly with plumber’s grease before reinstalling the spout.
For leaks under the sink, use a dry paper towel to test each connection. Check the hot and cold supply lines, shutoff valves, faucet shanks, and drain fittings one at a time. A loose nut may only need gentle tightening, but do not over-tighten plastic fittings or corroded metal connections. If a braided supply line is rusted, bulging, or dripping, replace it rather than trying to patch it.
Know when a faucet repair should become a service call
DIY repair makes sense when the issue is clearly limited to an aerator, handle screw, standard cartridge, or accessible supply connection. It becomes less predictable when the fixture is heavily corroded, the shutoff valves fail, parts are hard to identify, or a leak has already damaged the cabinet or wall.
Call a plumber if you notice any of these signs:
- Water continues leaking after the shutoff valves are closed.
- The faucet body is cracked, loose, or badly corroded.
- There is mold, soft wood, or staining inside the vanity.
- Water pressure is low throughout the home or in several fixtures.
- You cannot remove a stuck cartridge without risking damage.
- The leak may be coming from pipes inside the wall.
A bathroom faucet replacement may be more cost-effective than repeated repairs when the fixture is old, parts are discontinued, or the finish and internal components are deteriorating. On the other hand, a quality faucet with a replaceable cartridge can often provide many more years of reliable service with a straightforward repair.
Protect your faucet after the repair
Once the faucet is working properly, a few habits can help prevent another problem. Clean the aerator periodically, especially if you see reduced flow. Avoid hanging heavy items from the faucet neck or handles. Check under the sink occasionally for moisture, corrosion, or slow drips before they damage the cabinet.
If your home has hard water, mineral deposits can shorten the life of cartridges, aerators, and seals throughout the bathroom. Treating the water issue can reduce buildup and help fixtures operate more reliably over time.
When a repair feels uncertain, stopping before a small leak becomes a damaged vanity is the right call. San Antonio Plumbing can diagnose the source, explain the repair clearly, and help restore your bathroom faucet with dependable workmanship backed by a one-year repair guarantee.