A dripping faucet is the most common plumbing repair in a home, and one of the cheapest to fix yourself. The worn parts cost a few dollars, and the job takes about thirty minutes with basic hand tools. The repair approach depends entirely on the faucet design, so the first step is identifying what is under the handle. Understanding faucet types and mounting options before you open the valve body saves you from buying the wrong parts and from taking apart a mechanism you cannot reassemble.
Assess the Leak and the Damage It Causes
Not every drip means the same repair. Where the water appears tells you which part failed, and a leak that has run for weeks may have already damaged the cabinet, wall, or floor below. Look at the faucet with a dry cloth handy, run both handles, and note the exact place water appears before you order anything. Confirm that the shutoff valves under the sink turn freely before you begin, because you will need them closed for the repair.
Types of Faucet Leaks
- Drip from the spout: worn seat or washer
- Leak around the handle: failing stem packing or O-ring
- Water pooling at the base: loose valve body or supply connection
- Sprayer drip: separate cartridge or seat in the sprayer head
Check the Surrounding Materials
Before repairing anything, look for water stains, swollen wood, and flaking finishes. A slow leak that runs behind the cabinet can saturate drywall and soak a concrete slab for months without being obvious. The same concrete deterioration and repair principles apply to a sink base as to a bridge deck: moisture attacks the material, and the fix requires removing the damaged layer before patching. Catching that damage early is the difference between a parts replacement and a remodel.
Know the Faucet Type: Stem vs. Cartridge
Two-handle bathroom and kitchen faucets are usually stem-style faucets. A neoprene valve seat and spring fit into the water inlet port in the valve body, the stem is held in place with a bonnet nut, and the handle attaches to the top of the stem. A true cartridge-style faucet looks similar but has no valve seats and springs, so its repair kit is a single cartridge instead of several small parts. Open the faucet with the water off before ordering parts, and match the stem or cartridge by the number stamped on it. Step-by-step references such as how to repair a leaky faucet follow the same sequence for both designs.
How a Stem Faucet Works
In a stem faucet, water enters the valve body, passes the neoprene valve seat and spring, and is stopped by the washer on the stem tip when the handle is closed. Turning the handle raises the stem, opens the seat, and lets water reach the spout. The hot and cold sides are separate assemblies, so a leak on one side points to that side’s parts. The stem threads through the bonnet nut, and the packing around the stem keeps water from climbing up past the handle; when that packing dries out, the leak appears at the handle instead of the spout.
Parts That Wear Out
Three parts fail most often. The neoprene valve seat develops grooves where water pressure and grit cut into it. The spring loses tension and stops holding the seat against the stem. The washer at the stem tip hardens and stops sealing. Each costs a dollar or two, and replacing them together fixes most drips.
Tools and Supplies
- Adjustable wrench or basin wrench
- Screwdriver for the handle screw
- Replacement valve seats, springs, and washers
- Plumber’s grease for stem threads
- Rags and a small container for trapped water
Replace the Valve Seat and Spring
With the faucet type confirmed, the repair takes about thirty minutes. Turn off the supply valves under the sink before opening anything, then work through the sequence in order. Set the small parts on a towel in the order they come off, because the spring and seat are easy to lose.
Step-by-Step Repair Sequence
- Shut off the water supply valves and open the faucet to drain the lines.
- Remove the handle screw and pull the handle off the stem.
- Unscrew the bonnet nut and lift out the stem.
- Remove the old valve seat and spring from the inlet port.
- Install the new seat and spring, greasing the threads lightly.
- Reinstall the stem, tighten the bonnet nut, and replace the handle.
- Turn the water back on and test both hot and cold positions.
Parts for a stem-style faucet run about $5 to $15, which is why most homeowners repair rather than replace. After the leak is stopped, check the surrounding finishes. Water-stained drywall behind the faucet should be cut out and patched; the methods for repairing holes in drywall apply directly, and patching before the stain sets keeps the repair invisible.
Testing for Residual Leaks
Run the faucet for a minute on both handles, then check under the sink with a dry rag. A drip at the spout means the seat or washer is still not seating; a leak at the handle means the bonnet nut needs more torque or the stem packing is worn. Recheck the same spots again the next morning, because a slow seep can take hours to show.
Repair Water Damage to Concrete and Structure
A leak that ran for months can leave more than a stain. Water follows the path of least resistance, and in a slab-on-grade house it reaches the concrete floor, the shower pan, or the wall footing. Repairing the damaged material matters as much as fixing the faucet, because damp concrete stays damp and keeps feeding mold and corrosion.
Assessing Slabs and Shower Pans
Check for spalling, cracking, and efflorescence on concrete near the plumbing. Shallow surface damage can be ground and patched, but deeper deterioration needs evaluation. Professional repair and rehabilitation of concrete structures starts with determining the cause of the damage, then matches the repair material to the exposure, and the same logic applies to a bathroom floor slab. If the slab is still damp, wait for it to dry before patching, because repair materials will not bond to a wet surface.
Drying Out the Assembly
Run a dehumidifier or fan for several days before closing walls back up. Replace insulation that stayed wet and treat framing with a borate-based preservative if it shows staining. The goal is a dry cavity before the drywall goes back, and the table below maps the common symptoms to the parts that fix them.
| Symptom | Likely cause | Part to replace |
|---|---|---|
| Drip from the spout | Worn valve seat or washer | Seat, spring, washer |
| Leak at the handle | Failed stem packing | Packing or O-ring |
| Pooling at the base | Loose supply connection | Supply nut and gasket |
| Low flow on one side | Clogged aerator or screen | Aerator or screen |
When to Call a Professional
Stem faucets are beginner-friendly, but some conditions belong to a licensed plumber. If the shutoff valves under the sink do not work, if the valve body is corroded or cracked, or if the leak returns after new seats and springs, stop and call for help. Working on a supply line you cannot isolate is how basements flood.
Signs You Should Stop and Call
- Shutoff valves will not close or leak when operated
- The valve body is cracked, corroded, or stripped at the threads
- The leak persists after replacing seats, springs, and washers
- Water has damaged walls, floors, or framing beyond surface stains
- The faucet is a cartridge type with no replacement cartridge available
What a Professional Will Check
A plumber isolates the supply, inspects the valve body, and tests water pressure, a frequent hidden cause of repeat leaks. If the leak reached the structure, a structural engineer assesses cracks in foundations, walls, and columns. Repair of concrete columns for cracks and damage is a specialized job that starts with diagnosis and ends with epoxy or grout injection, not a surface patch.
Preventive Maintenance That Extends Faucet Life
Most faucet leaks come from hard water deposits and worn rubber parts, both of which are manageable with routine care. A few minutes of maintenance every season keeps the repair from becoming a replacement.
Seasonal Checks
- Exercise shutoff valves twice a year to keep them free
- Clean aerators and screens to remove grit that scores seats
- Tighten loose handles before they round out the stem splines
- Look under the sink for dampness after every use
Routine Care for Fixtures and Finishes
Wipe fixtures dry after use, skip abrasive cleaners on plated surfaces, and address drips within a week instead of waiting for the season. Plumbing is one system among several in the house; a schedule of routine building repair and maintenance catches small problems across all of them before they compound. A thirty-minute faucet repair today costs less than the drywall, concrete, and cabinet work a neglected leak forces later. Keep spare seats and springs on hand, since the same parts fit most two-handle models from the same manufacturer.