Sink Leaks · Loveland, CO · Larimer County
Sink Leak Detection & Repair in Loveland, CO
The cabinet floor under a sink is a logbook. A dark ring under the trap. Particleboard swelling at the seams. A warp under the supply stops. Each mark records a different leak, and reading them right means fixing the true failure instead of the loudest suspect.
Six Suspects Under One Basin
A sink assembly packs more connections per square foot than anywhere else in the house. Supply side: two stops, two supply lines, and the faucet tails they feed. Drain side: basket strainer or drain flange, tailpiece, trap, and the trap arm into the wall. Kitchens add a disposal, a dishwasher drain loop, and often a filter or instant-hot system squeezed in by whoever owned the house last. Any of them can be the source of the puddle, and several can leak at once.
The order of testing matters. Supply-side leaks run constantly and show with everything off. Drain-side leaks only appear under flow, so we fill and release the basin while watching every joint with a dry hand and a flashlight. Sprayer hoses get pulled through their arc, since some only weep at full extension. Ten organized minutes usually names the failure exactly.
Kitchen Sinks: Where the Traffic Is
Kitchen sinks do more work than every bathroom fixture combined, and their leaks follow the workload. Basket strainers loosen from years of pot impacts and thermal cycling, letting dishwater past the putty a drop at a time. Trap joints get knocked out of alignment by stored cleaning supplies. Disposal connections, the splash guard mount and the dishwasher inlet, weep where vibration works them loose, a story covered fully on the disposal page.
The newer kitchens around Crossroads and the eastern build-out add their own pattern. Deep single-basin sinks get retrofitted with aftermarket filtration, and the saddle valves and push-fit tees installed in a weekend become the leak two winters later. We rework those connections to proper fittings while the cabinet is open.
The Basin Seal and the Counter Seam
Not every sink leak is plumbing. Undermount basins hang from adhesive and clips, and when that bond ages, rinse water tracks the gap between basin rim and counter, arriving at the cabinet floor along a path no pipe explains. Drop-in sinks do the same trick through failed caulk at the deck. The tell is water appearing only after basin-filling use, splashy dishwashing or a bath in a bathroom sink, with every joint below testing dry.
The fix is mechanical rather than plumbed: re-supporting the basin, cleaning and resealing the seam, and correcting whatever let it sag. Miss this diagnosis and a household replaces trap parts twice while the counter seam keeps feeding the rot.
What Water Does to a Cabinet, and When to Say So
Particleboard cabinets absorb slow leaks like a sponge and give the evidence back as swelling, delamination, and a musty smell that outlasts the fix. Part of an honest sink call is grading that damage plainly. Surface staining that dries and holds is one thing. Floor panels gone structurally soft are another. Moisture that has already moved into the toe kick and the flooring beyond is a third. The plumbing repair stops the source; the household deserves to know what the water already did.
Where the trail leads past the cabinet, into the wall behind or the floor below, the job escalates to drain-line testing or moisture mapping rather than guesswork. Most sink calls end at the cabinet. The ones that should not, should not.
Same-Visit Fixes, Almost Always
Sink work rewards preparation: trap kits, supply lines, stops, strainers, and putty ride on the truck, so the visit that diagnoses usually also repairs. You approve the price after the ten-minute test, the work happens with the cabinet contents set aside on a drop cloth, and the joints get retested under flow before anything gets put back.
A slow drip under a sink is the cheapest leak you will ever fix and the most expensive one to ignore for a year. (303) 552-3896 reaches us any hour, and yes, the 2 a.m. version with a burst supply line counts as the emergency it feels like.
✆ Call (303) 552-3896Under-Sink Questions
The leak only happens when the dishwasher runs. Sink problem?
It shares the cabinet, so it lands on this call either way. The usual culprits are the dishwasher drain connection at the disposal or tailpiece, a missing high loop letting water siphon, or the supply tee under the sink. Running a cycle while watching the connections identifies it in one pass.
Why does the trap leak only sometimes?
Intermittent trap leaks track use and alignment. A joint knocked slightly off-axis seals at low flow and weeps when the basin dumps full. Slip-joint washers also harden with age and seal only until temperature swings move them. Replacing the washers and re-aligning the run ends the sometimes.
There is a white crusty ring on the cabinet floor but everything feels dry.
That crust is mineral residue from a leak that ran and stopped, or runs rarely, and it marks the drip point like chalk at a crime scene. Directly above it sits your suspect. It deserves the full flow test even if today is a dry day, because sometimes-leaks pick their moments.
Should supply lines under sinks be replaced preventively?
Braided stainless lines are cheap insurance and worth swapping when they show rust at the crimps, kinks, or age past ten years or so. The rubber core inside ages whether or not the braid looks fine. While we are under any sink, a thirty-second inspection of the lines and stops is standard.