Dripping Faucet: Diagnose and Fix

The water waste from a dripping faucet is specific and measurable. Per undefined, a faucet dripping at one drip per second wastes approximately 3,000 gallons per year. At the national average water rate of roughly $8 per thousand gallons, that's $24/year — modest at the slow end. But one drip per second is a conservative starting point.

The actual cost escalation

A faucet dripping at 10 drips per second — which still looks like "just a drip" to most homeowners — wastes roughly 15,000–20,000 gallons per year, translating to $120–$160 annually in water cost alone. A visible thin stream wastes even more. Multiply this across two or three dripping fixtures in a home and the annual water cost becomes significant.

The real reason to fix it promptly

Water cost isn't the most important reason to repair a dripping faucet. The more consequential damage is what happens to the valve seat — the metal or ceramic surface the cartridge or washer presses against to stop flow. A steady drip erodes this surface through mineral deposit buildup and mechanical wear. A $30 cartridge repair deferred for 6 months can become a $150–$250 faucet replacement once the valve seat is damaged, because no new cartridge will seal against a pitted or corroded seat.

The payback period for a $75–$150 professional repair is 6–18 months in water savings alone. The payback period for preventing valve seat damage is immediate — every week of delay moves the repair from "replace a cartridge" toward "replace the faucet."

Before you buy parts or call a plumber, identify which type of faucet you have. There are four residential types and each has a distinct internal mechanism, a different failure mode, and a different repair approach. Getting this wrong means buying the wrong parts.

Compression faucet (two separate handles, older construction)

The oldest and simplest design. A rubber washer presses against a brass seat at the bottom of the valve stem to stop flow. The washer flattens and hardens over time, allowing water to seep past. Very DIY-friendly — remove the handle, remove the packing nut, pull the stem, and replace the washer at the bottom. Parts cost: $2–$5. Found most commonly in pre-1970s construction and in low-cost fixtures. The telltale sign: the handle gets harder to turn as the faucet ages (you're compressing the increasingly stiff washer harder to stop the drip).

Ball faucet (single handle that rotates and pivots)

A spring-loaded ball with ports controls both flow and temperature mixing by rotating to align with or block supply ports. Drips typically originate from failed O-rings on the ball, worn seats and springs, or a worn ball with surface pitting. More complex to repair than compression; ball faucet rebuild kits ($15–$30) include all wearing parts (ball, O-rings, seats, springs) and are the right approach when this type drips. Disassembly is more involved — the handle, cap, collar, and ball must all be removed in sequence.

Cartridge faucet (single or double handle, post-1980 construction)

The most common type in homes built after 1980. A plastic or brass cartridge sleeve controls both flow volume and temperature. The cartridge contains all the wearing surfaces internally, which makes repair straightforward: identify the brand and model, buy the matching replacement cartridge, pull the old one, install the new one in the correct orientation. Cartridges cost $10–$40 depending on brand. The critical step is noting the cartridge orientation before removal — installing it rotated 180° reverses the hot and cold supply.

Ceramic-disc faucet (single lever with a wide cylindrical body)

The most durable residential design. Two ceramic discs rotate against each other to control flow — ceramic is extremely hard and resists mineral deposits. These faucets rarely drip from disc failure; when they do drip, it's almost always from O-ring failure on the cartridge housing or mineral buildup on the disc surfaces. Repair: remove the cartridge, clean the disc surfaces with white vinegar, replace the O-rings. Full ceramic disc cartridges last 15–25 years under normal use.

Cartridge replacement is the repair performed on the majority of dripping kitchen and bathroom faucets in post-1980 homes. It requires no special tools beyond a screwdriver, slip-joint pliers, and a cartridge puller tool for seized cartridges. Parts cost is $10–$40 for the cartridge. A plumber can complete the repair in 30–60 minutes.

Step-by-step procedure

1. Turn off the angle-stop shutoffs under the sink — the two valves on the supply lines leading up to the faucet. If either angle-stop won't fully close (see the angle-stop section below), shut off the main water supply to the house instead.
2. Open the faucet handle to release pressure and confirm the water is off.
3. Remove the handle. Most faucet handles have a screw hidden under a decorative cap on the top or back of the handle. Pry the cap off with a flat screwdriver, remove the screw, and lift or pull the handle off.
4. Take a photo of the cartridge orientation before touching anything. The cartridge must go back in the same rotational position — hot to the left, cold to the right — or the handles will work in reverse.
5. Remove the retaining clip or nut that holds the cartridge in place. This varies by brand.
6. Pull the cartridge straight out. Some cartridges pull out easily; others are seized from mineral deposits. A cartridge puller tool (available at hardware stores, $10–$15) grips the cartridge stem and provides the straight-pull force needed without damaging the valve body.
7. Match the cartridge at a plumbing supply store or hardware store. Bring the old cartridge and note the faucet brand (usually marked on the body or under the handle). Brand-specific cartridges are not interchangeable.
8. Install the new cartridge in the same orientation. Apply a thin coat of plumber's grease to the O-rings before installation.
9. Reassemble, turn the water back on slowly, and test.

If the drip returns within 6 months

A cartridge that's replaced and drips again within weeks or months indicates the valve seat is damaged. The new cartridge cannot seal against a pitted or corroded seat surface. At this point, you're facing a choice between valve seat resurfacing or faucet replacement — covered in the next section.

Professional repair cost: $10–$40 for the cartridge plus $75–$150 for a plumber's labor, totaling $85–$190 per BuildZoom contractor cost data, depending on market and faucet brand.

The valve seat is the precision surface — brass, bronze, or ceramic depending on the faucet — that the cartridge or washer presses against to create a watertight seal. When this surface degrades, no cartridge replacement will fix the drip permanently. The new cartridge seals against a damaged surface, wears rapidly, and the drip returns within weeks or months.

What damages valve seats

Two primary causes: mineral deposits and mechanical erosion from the steady dripping itself. In hard-water markets, undefined data shows that water above 10 grains per gallon — which includes Phoenix, Las Vegas, Denver, Indianapolis, Dallas, Houston, and most of the Southwest and Mountain West — deposits calcium carbonate scale on all wetted surfaces including valve seats. Above 15 GPG, this scale buildup can pit a brass valve seat within 3–5 years in some faucet materials. Once the drip starts and continues without repair, the steady stream of water erodes the seat surface further — which is why prompt repair matters.

Signs of valve seat damage

• A new cartridge was installed within the past 6–12 months and the faucet is dripping again
• Visible discoloration, roughness, or pitting on the seat surface when you look into the valve body with a flashlight after cartridge removal
• The faucet has been dripping for an extended period without repair

Fix options

Option 1 — Resurface with a seat grinder tool: A valve seat grinder is a specialty tool ($25 to purchase, or borrowable from a tool library) that resurfaces the seat with a rotating abrasive tip. This is DIY-feasible for a confident homeowner and costs nothing in parts. The limitation: it works only on replaceable brass seats, not on ceramic or non-removable seats.

Option 2 — Replace the faucet: Often the more economical choice when the faucet is over 10 years old. A new faucet provides fresh valve seats, a new cartridge, intact O-rings, and a manufacturer warranty — all for $175–$400 installed for a mid-range unit. This is almost always the right answer when the faucet is aging and the valve seat is visibly damaged.

There is one risk in faucet repair that doesn't appear on any parts list and isn't obvious until the moment you try to turn off the water: the angle-stop shutoff valve under the sink may not work.

What an angle-stop is and why it fails

The angle-stop is the small shutoff valve where the supply line connects to the water supply stub-out coming out of the wall or floor under the sink. Most homes have two (hot and cold), and most of them are gate valve or ball valve design, installed when the house was built, and never exercised since. A valve that has sat fully open for 15–30 years develops mineral deposits on the stem, corrosion at the seat, and often a packing gasket that has dried out and cracked.

What happens when an old angle-stop fails

Three failure modes:

• The valve turns but water doesn't stop — the seat is so corroded or scaled that it no longer seals. You're now doing a faucet repair with water running.
• The valve closes but the stem leaks when you open it after the repair — the packing gasket fails when the stem is moved for the first time in years.
• The valve handle breaks off entirely under torque — corroded brass is brittle. This is the scenario that requires an immediate main shutoff.

What to do about it

If the home has original angle-stops that are 20+ years old, have a plumber assess their condition before committing to a faucet repair. Replacing angle-stops at the same time as a faucet repair adds $75–$150 per fixture for parts and labor — but it prevents the scenario where a routine $100 cartridge replacement becomes an emergency main shutoff call with water running under the sink. Quarter-turn ball valve angle-stops are the standard replacement per IAPMO Uniform Plumbing Code and will last another 20+ years.

Most dripping faucets are worth repairing. But there is a clear set of conditions where replacement is the smarter investment — and identifying them before committing to a repair saves money.

Repair when all of these are true

• The faucet body is structurally sound — no cracks, no corrosion on the valve body
• The brand and cartridge type are identifiable and parts are available
• The faucet is under 10 years old
• The finish is intact — no chrome flaking, no significant pitting
• The faucet is dripping from the spout only (single failure point)

Replace when any of these apply

• The faucet is leaking from the spout AND from the base — two separate seal failures simultaneously indicate the faucet has reached end of life across multiple components
• The finish is deteriorating — chrome flaking, brass pitting, nickel corrosion indicates the surface coating has failed and the underlying metal is degrading
• It's a builder-grade no-name fixture installed during original construction — these are typically minimum-code units with poor parts availability and short service lives; replacement with a quality unit is the right long-term move
• The home is being prepared for sale — buyers and home inspectors notice dripping and deteriorated fixtures; a new faucet is a high-visibility improvement
• The faucet is a pre-1990s unit with unavailable cartridges — if you cannot source the replacement cartridge, you cannot repair it

Replacement cost

A licensed plumber installs a mid-range faucet (supplied by the homeowner) in 45–90 minutes: $75–$150 in labor. A plumber-supplied mid-range kitchen or bathroom faucet plus installation: $200–$450 total per BLS Plumbers, Pipefitters & Steamfitters wage data (OES 47-2152), with geographic labor rate variation driving most of the spread.

In hard-water markets, buying the wrong replacement faucet is a common and expensive mistake. The faucet that performs well for 15 years in Seattle or Portland may fail in 4–5 years in Phoenix or Las Vegas — not because of different use patterns, but because of water chemistry.

Why hard water attacks faucets

Per undefined, water above 10 GPG carries dissolved calcium and magnesium that deposits as scale on every internal surface: cartridge O-rings, valve seats, aerator screens, and the faucet body's internal passages. The corrosive interaction between hard water and lower-quality alloys — particularly zinc die-cast — degrades valve internals at an accelerated rate. Above 15 GPG, the correlation between water hardness and accelerated fixture failure is well-documented and is a fundamental buying consideration, not just a maintenance issue.

What to specify in a hard-water market

• Solid brass valve body — not zinc die-cast. Zinc die-cast corrodes in high-mineral water within 3–5 years. Solid brass resists mineral attack significantly better. This spec is often listed in faucet product descriptions; if it doesn't say "solid brass," assume it isn't.
• Ceramic cartridge — over rubber washer or composite designs. Ceramic surfaces resist mineral deposit adhesion and do not degrade from the mineral-acidic chemistry the way rubber does.
• Readily available replacement cartridges — choose a brand with reliable domestic parts supply. A great faucet that requires a 6-week special order for a cartridge is a poor choice for a rental property or a household that can't tolerate downtime.

Routine maintenance in hard-water markets

Descale the aerator (the small screen at the faucet tip) quarterly by unscrewing it and soaking in white vinegar for 30 minutes. A clogged aerator restricts flow and is often misdiagnosed as a pressure problem. Descale the showerhead monthly using the same vinegar soak method. These two steps add years to fixture life in hard-water markets and cost nothing.