How do I tell where my kitchen faucet is leaking from?

Dry everything under the sink with a towel, lay paper towels on the cabinet floor, then run the faucet through its positions: off, on hot, on cold, sprayer engaged. Where the paper towel spots first — supply connection, faucet base through the counter hole, sprayer hose, or drain — is your leak. Off-cycle spotting means a pressurized supply-side leak, the urgent kind.

Is a faucet leak under the sink an emergency?

A supply-side leak (wet with the faucet off) is pressurized 24/7 and should be shut off at the valves today. A leak that only appears when the faucet runs is urgent-ish: every use adds water to a closed cabinet that cannot dry, so 'I'll fix it eventually' is how cabinet floors and subfloors get ruined.

Why does my faucet leak around its base when I run it?

The O-rings or the seal where the faucet body meets the sink deck have worn. Water pools at the base and follows the faucet's mounting holes straight through the counter into the cabinet — so a 'harmless' base leak is usually also an under-counter leak.

What does a chronically damp sink cabinet do to a kitchen?

The particleboard cabinet floor swells and delaminates, the cabinet back wicks moisture into the wall behind it, and the enclosed humidity supports mold on every surface inside. From there it moves to the subfloor and adjacent cabinets. Slow leaks ruin kitchens by installments.

Will insurance pay for damage from a leaking faucet?

The sudden version — a supply connection lets go — is commonly covered. The slow version, a drip that ran for months, is the textbook gradual-damage dispute. Discovery date, immediate action, and a moisture map are what keep a slow-leak claim viable.

Repair or replace the faucet?

Cartridge, O-rings, or a supply line on a decent faucet: repair. A budget faucet past ten years leaking from the body: replace — and upgrade the supply lines to braided stainless while everything is apart.

What causes a kitchen faucet to leak under the sink?

Four things: worn supply line connections that crack, O-ring seals at the faucet base that deteriorate, sprayer hose quick-connects that loosen, or drain traps that crack. Supply leaks drip constantly. Base and sprayer leaks only happen when you run water. The diagnostic is simple — dry everything, run the faucet, and watch where wet appears first.

How much water is actually wasting from a slow kitchen faucet leak?

A single drip per second is 2,600 gallons a year. Under the cabinet where you can't see it, that's months of saturation before you notice. Houston's humidity makes it worse — the cabinet never dries. One homeowner I worked with had a supply leak that filled a five-gallon bucket in three days. By the time she saw the bill, her cabinet floor was rotted and the subfloor was wet.

The cabinet floor is swollen. Does the whole cabinet have to come out?

Often just the floor panel, not the box. A swollen particleboard deck can be cut out and replaced with plywood for a fraction of a new cabinet, and doing it that way is the only honest way to see the subfloor underneath. Full replacement enters the conversation when the sides have wicked upward, the face frame is soft, or the back panel has separated from the wall.

How do I dry inside a sink cabinet myself after the leak is fixed?

Empty it completely, take the doors off their hinges, and put a small fan blowing into the cabinet rather than across the front of it. Add a dehumidifier in the room and keep the kitchen closed off from the rest of the house. Give it three or four days, then push a thumb hard into the back corners of the deck — any give means the core is still wet and surface air was never reaching it.

Is the mold under my sink dangerous, or just ugly?

The dark spotting on the underside of a wet cabinet deck is real growth, and disturbing it dry — scrubbing or sanding — puts spores into the kitchen air. Small growth on a hard, non-porous surface can be cleaned. Growth on swollen particleboard cannot, because the material absorbed it, so the panel gets replaced. Anyone in the house with asthma should be out of the room while it comes out.

What does it cost to dry the cabinet and subfloor?

A single sink cabinet with the deck removed and a few days of equipment usually runs in the high hundreds. It climbs into the low thousands when the water tracked under the flooring into the room, when adjacent cabinets are involved, or when a section of subfloor has to be cut out and replaced. Removal, not drying time, is what moves the number.

I am selling the house. Do I have to disclose an old faucet leak?

The Texas seller's disclosure notice asks directly about previous water damage and known mold, and answering it wrong is the kind of thing that follows a sale. The version that helps you is a documented repair — the invoice, moisture readings showing dry standard, a photo of the replaced cabinet deck. A disclosed and documented leak is a footnote. An undisclosed one that an inspector finds is a renegotiation.

Why does almost every Houston house end up with a wet sink cabinet eventually?

Two local conditions stack. Houston-area water runs around 10 grains per gallon of hardness, and those minerals build at compression fittings and aerators until a fitting stops sealing. Then the humidity keeps the closed cabinet at a moisture level where nothing dries between drips — a sink cabinet in Pearland in August has no dry season. The same slow leak that evaporates in a dry climate simply accumulates here.

Water Damage · August 15, 2026

Kitchen Faucet Leak: Find Out Which of the Four Leaks You Have

A kitchen faucet can leak at the spout, the base, or — worst — under the counter at its supply connections, where it drips into the cabinet for months. How to find which leak you have and what the cabinet is hiding.

The short answer

Open the cabinet and touch everything with a dry hand: supply connections, faucet mount, sprayer hose, drain. Wet with the faucet **off** means a pressurized supply leak — close the shut-off valves under the sink now. Wet only when running means seals or drain-side — fix it this week, because every use waters a closed cabinet that cannot dry. Either way, pull everything out of the cabinet and check its floor: that is where months of drips have been landing.

A moisture meter showing 15.7% sits on a water-damaged cabinet floor with visible mold growth and a leaking sink drain. Caption on image: FIND THE SOURCE. DRY WHAT YOU CANNOT SEE.

The four kitchen faucet leaks

1. Supply connections (under the counter). The braided or plastic lines from the shut-off valves to the faucet, pressurized around the clock. The most damaging version because it drips at 3 a.m. as reliably as at dinner.

2. Faucet base (at the deck). Worn O-rings let running water pool at the base — and drain through the mounting holes into the cabinet. Looks cosmetic from above; isn’t.

3. Sprayer/pull-down hose. The hose or its quick-connect weeps inside the cabinet when the sprayer runs, then hangs there dripping.

4. Spout drip. The classic worn-cartridge drip into the basin. Annoying and wasteful, but the only one of the four that isn’t a water-damage risk — the water lands in the drain.

Warning signs you have been leaking for months

The cabinet is telling you first:

A dark tide line along the back edge of the cabinet floor, or a deck that flexes under a thumb
Cleaning-supply bottles with rusted bases or peeling labels
Dark spotting on the underside of the deck, visible only when you empty the cabinet and look up from the toe-kick

The room is telling you second:

A musty smell that returns within a day of cleaning — a smell like that is a moisture finding before it is anything else
Flooring in front of the sink darkening at the seams or lifting at the edges
Baseboard beside or behind the cabinet swelling along its bottom inch

The fittings are telling you why: green or white crust at a compression nut, a supply line gone stiff and chalky, an aerator that needs soaking every few months. Houston water runs around 10 grains per gallon of hardness, and those minerals build at every fitting until one stops sealing.

The paper towel diagnostic

Ten minutes, definitive:

Towel-dry every line, fitting, and surface in the cabinet.
Lay dry paper towels across the cabinet floor and under the trap.
Run the sequence: faucet off 10 minutes → hot on → cold on → sprayer → fill and drain the basin.
Check the towels after each step. First wet spot = your leak, and which step produced it = supply, base/sprayer, or drain-side.

Wet during the off phase is your cue to close both shut-off valves and treat it as today’s problem.

What the cabinet floor is hiding

Sink cabinets are where slow leaks go to work unobserved: dark, closed, full of cleaning supplies nobody moves for months. By the time a drip is noticed, the pattern we find is consistent —

Cabinet floor (particleboard) swollen, delaminating, often moldy on the underside
The wall behind the cabinet wicking moisture upward
Subfloor beneath reading wet in a radius the cabinet hides
In slab homes, moisture tracked sideways under adjacent flooring

That is why the checklist below says empty the cabinet — not glance in it.

What to do right now

Shut-off valves closed if the leak is supply-side (or the house main if the valves are seized — then have those valves replaced too).
Empty the cabinet completely. Everything out, doors open.
Photograph the cabinet interior as found — swelling, staining, mold, the leak point.
Fix the leak: tighten/replace the supply line, reseat the faucet with new O-rings, re-clamp the sprayer connect — or call a plumber for anything seized.
Judge the moisture honestly. Swollen cabinet floor, staining beyond the cabinet, musty smell = get it metered. Cabinet interiors and the subfloor below are exactly where Houston humidity keeps water alive for weeks. Photo to (346) 271-7004 gets you a straight answer.

What does a wet sink cabinet cost to put right?

The faucet is the cheap half — a cartridge, a set of O-rings, or braided supply lines is parts-store money and an afternoon. The cabinet and what is under it are the number nobody quotes on the phone, so here are the variables.

How long it dripped. A week is a dry-out. Six months is a dry-out plus a cabinet deck plus, often, remediation.
Whether the deck comes out. A swollen particleboard deck can be cut out and replaced with plywood for a fraction of a new cabinet, and that is the only honest way to read the subfloor beneath.
How far the water traveled. Slab-on-grade construction covers most of the Houston area, so water leaving the cabinet spreads sideways across the slab under the flooring. The wet zone routinely meters two or three feet past the last visible stain.
Whether growth started. Dark spotting on swollen particleboard is not cleanable — the material absorbed it, and that is a remediation rather than a drying job.

A single sink cabinet with the deck removed and a few days of equipment usually runs in the high hundreds. It moves into the low thousands once water tracked out under the kitchen flooring or a section of subfloor has to be cut and replaced. Removal drives the number, not drying time — the structure is in what mitigation costs in Houston.

How long does the drying take?

Three to five days for a single cabinet, once it is emptied, the doors are off their hinges, and an air mover is pushing into the box rather than across the front of it. Longer when the deck came out and the subfloor was wet, longer again when water reached the wall cavity behind.

Readings decide the end date, not the calendar. Deck, subfloor and the bottom plate of the wall behind all have to hit dry standard before anything goes back in. A useful home check meanwhile: after three or four days of air, push a thumb hard into the back corners of the deck — any give means the core is still wet and the air was never reaching it. More on what sets a drying timeline.

Does insurance cover a leaking kitchen faucet?

The sudden version — a supply connection lets go and the cabinet floods — is commonly covered as sudden and accidental discharge. The slow version, a weep that ran for months under a cabinet full of cleaning supplies, is the textbook gradual-damage dispute, and carriers deny it routinely.

Three things keep a slow-leak claim alive: a discovery date with photographs taken that day, evidence you acted immediately, and a professional moisture map showing the real extent rather than the visible stain. The faucet repair itself is generally your cost either way — policies cover what the water damaged, not the part that failed. If a claim comes back denied, there is usually a specific reason and a route back.

What NOT to do

Don’t put the cleaning supplies back over a damp cabinet floor — you are re-covering the evidence and blocking the drying.
Don’t seal a swollen cabinet floor with paint or contact paper. Moisture in, mold next.
Don’t hand-tighten a weeping compression fitting “one more turn” repeatedly — over-torqued ferrules crack, and the weep becomes a spray.

The free things worth doing tonight

Close both shut-off valves if anything was wet with the faucet off.
Empty the cabinet completely — every bottle, every sponge — and take the doors off their hinges.
Push a thumb hard into the deck at the back corners and along the front edge. Give means the core took water.
Look up at the underside of the deck from the toe-kick with a flashlight. Growth shows there first.
Point a fan into the cabinet, not across the front of it, and shut the kitchen off from the rest of the house.
Photograph everything with the date stamp on and write down today’s date as the discovery date.

Prevention

Braided stainless supply lines, replaced on their warranty windows
Exercise the shut-off valves twice a year so they close when needed
A $15 water alarm on the cabinet floor — the single best return-on-investment in the kitchen
Add the sink cabinet to your twice-yearly walkthrough: one touch of the trap and lines with dry fingers

Where the plumber ends and we begin

TruePoint Restoration is not a plumbing company and not a cabinet shop. We do not replace faucets, re-run supply lines, swap cartridges, or build you a new sink base, and we say so on the phone rather than after the estimate. A seized shut-off valve, a corroded compression fitting, or a faucet that needs pulling is a plumber’s work, and the two trades are not interchangeable.

What we do is the water the plumber leaves behind: metering the cabinet deck, the subfloor, the wall bottom and the flooring out into the room, removing what cannot be dried, drying the rest with commercial equipment and logged daily readings, and handing you a documented file your adjuster can work from.

Sometimes the honest answer is that an empty cabinet, an open door and a fan will do it — and we would rather say that than sell you equipment days you do not need. Send photos to (346) 271-7004. We serve Pearland, Manvel, Friendswood, League City and the Greater Houston area.

A technician wearing gloves kneels on a kitchen floor, reaching into a cabinet to inspect plumbing under a sink.

Questions, answered

Kitchen Faucet Leak Questions

How do I tell where my kitchen faucet is leaking from?: Dry everything under the sink with a towel, lay paper towels on the cabinet floor, then run the faucet through its positions: off, on hot, on cold, sprayer engaged. Where the paper towel spots first — supply connection, faucet base through the counter hole, sprayer hose, or drain — is your leak. Off-cycle spotting means a pressurized supply-side leak, the urgent kind.
Is a faucet leak under the sink an emergency?: A supply-side leak (wet with the faucet off) is pressurized 24/7 and should be shut off at the valves today. A leak that only appears when the faucet runs is urgent-ish: every use adds water to a closed cabinet that cannot dry, so 'I'll fix it eventually' is how cabinet floors and subfloors get ruined.
Why does my faucet leak around its base when I run it?: The O-rings or the seal where the faucet body meets the sink deck have worn. Water pools at the base and follows the faucet's mounting holes straight through the counter into the cabinet — so a 'harmless' base leak is usually also an under-counter leak.
What does a chronically damp sink cabinet do to a kitchen?: The particleboard cabinet floor swells and delaminates, the cabinet back wicks moisture into the wall behind it, and the enclosed humidity supports mold on every surface inside. From there it moves to the subfloor and adjacent cabinets. Slow leaks ruin kitchens by installments.
Will insurance pay for damage from a leaking faucet?: The sudden version — a supply connection lets go — is commonly covered. The slow version, a drip that ran for months, is the textbook gradual-damage dispute. Discovery date, immediate action, and a moisture map are what keep a slow-leak claim viable.
Repair or replace the faucet?: Cartridge, O-rings, or a supply line on a decent faucet: repair. A budget faucet past ten years leaking from the body: replace — and upgrade the supply lines to braided stainless while everything is apart.
What causes a kitchen faucet to leak under the sink?: Four things: worn supply line connections that crack, O-ring seals at the faucet base that deteriorate, sprayer hose quick-connects that loosen, or drain traps that crack. Supply leaks drip constantly. Base and sprayer leaks only happen when you run water. The diagnostic is simple — dry everything, run the faucet, and watch where wet appears first.
How much water is actually wasting from a slow kitchen faucet leak?: A single drip per second is 2,600 gallons a year. Under the cabinet where you can't see it, that's months of saturation before you notice. Houston's humidity makes it worse — the cabinet never dries. One homeowner I worked with had a supply leak that filled a five-gallon bucket in three days. By the time she saw the bill, her cabinet floor was rotted and the subfloor was wet.
The cabinet floor is swollen. Does the whole cabinet have to come out?: Often just the floor panel, not the box. A swollen particleboard deck can be cut out and replaced with plywood for a fraction of a new cabinet, and doing it that way is the only honest way to see the subfloor underneath. Full replacement enters the conversation when the sides have wicked upward, the face frame is soft, or the back panel has separated from the wall.
How do I dry inside a sink cabinet myself after the leak is fixed?: Empty it completely, take the doors off their hinges, and put a small fan blowing into the cabinet rather than across the front of it. Add a dehumidifier in the room and keep the kitchen closed off from the rest of the house. Give it three or four days, then push a thumb hard into the back corners of the deck — any give means the core is still wet and surface air was never reaching it.
Is the mold under my sink dangerous, or just ugly?: The dark spotting on the underside of a wet cabinet deck is real growth, and disturbing it dry — scrubbing or sanding — puts spores into the kitchen air. Small growth on a hard, non-porous surface can be cleaned. Growth on swollen particleboard cannot, because the material absorbed it, so the panel gets replaced. Anyone in the house with asthma should be out of the room while it comes out.
What does it cost to dry the cabinet and subfloor?: A single sink cabinet with the deck removed and a few days of equipment usually runs in the high hundreds. It climbs into the low thousands when the water tracked under the flooring into the room, when adjacent cabinets are involved, or when a section of subfloor has to be cut out and replaced. Removal, not drying time, is what moves the number.
I am selling the house. Do I have to disclose an old faucet leak?: The Texas seller's disclosure notice asks directly about previous water damage and known mold, and answering it wrong is the kind of thing that follows a sale. The version that helps you is a documented repair — the invoice, moisture readings showing dry standard, a photo of the replaced cabinet deck. A disclosed and documented leak is a footnote. An undisclosed one that an inspector finds is a renegotiation.
Why does almost every Houston house end up with a wet sink cabinet eventually?: Two local conditions stack. Houston-area water runs around 10 grains per gallon of hardness, and those minerals build at compression fittings and aerators until a fitting stops sealing. Then the humidity keeps the closed cabinet at a moisture level where nothing dries between drips — a sink cabinet in Pearland in August has no dry season. The same slow leak that evaporates in a dry climate simply accumulates here.

Water or fire damage right now?

Talk to someone who documents it properly.

Certified water and fire damage mitigation across Pearland, Manvel, Friendswood and the Greater Houston area. Text a photo of what you are seeing and we will tell you whether it needs professional drying.

Call or text (346) 271-7004