The short answer
A commercial cabinet leaking onto the floor has usually blocked or kinked its drain line, so defrost water backs up and escapes at the lowest edge. A damaged door gasket is second, because it loads the cabinet with humid kitchen air and makes more water than the drain was sized for. Both are checkable on site. Only an internal drain or evaporator fault is a service call.
What you observe
- Water appearing on the floor on a regular cycle — Timed with the defrost. Points at the drain line.
- Standing water in the bottom of the cabinet — The internal trough is not clearing to the drain.
- A drain line kinked behind or under the cabinet — Usually created by rolling the cabinet back into place.
- Heavy condensation or ice at the door line — A damaged gasket loading the cabinet with humid air.
- NEAR MISS — water only at a neighbouring sink or bench — Track it with paper towel before blaming the cabinet.
Causes, most likely first on this class
- Drain line blocked with grease and debris — First in a commercial kitchen because airborne grease reaches the trough and sets with debris into a plug. The cabinet then backs up and puts its water on the floor every defrost.
- Drain line kinked or lifted above the waste point — Second, and almost always caused by moving the cabinet. A line with no fall cannot drain no matter how clear it is.
- Door gasket damaged, making more water than the drain can take — Third: constant door traffic and trolley knocks wreck commercial gaskets, and the humid air they admit condenses heavily inside.
- Internal trough or evaporator drain fault — Last, and the only one needing a technician. Its tell is standing water inside the cabinet with a demonstrably clear external drain line.
Check in this order, and why
- Decide whether water appears inside, outside, or both — Inside means the trough; outside means the line.
- Follow the drain line for kinks and fall — Top cause, visible without tools, correctable on site.
- Flush the drain line with warm water — Confirms or clears a grease plug.
- Check the door gasket all the way round — Left until here because it explains volume rather than route.
What an owner can safely check
- Dry the floor and note when water returns — A regular cycle matches the defrost and confirms the drain.
Tools: mopAbout 15 min
- Trace the drain line from cabinet to waste point — Look for kinks, lifts and a line resting above its outlet.
Tools: torchAbout 20 min
- Flush the line and the internal trough with warm water — It should run away steadily. Backing up means a plug.
Tools: jug of warm waterAbout 20 min
- Test the door gasket with paper all round — Where it slides free, humid kitchen air is getting in.
Tools: sheet of paperAbout 15 min
- STOP HERE if water stands inside with a clear drain line — The internal trough or evaporator drain needs a technician.
Before you open anything
Safety
Isolate the cabinet at its switch or breaker before removing any panel or reaching into the trough; a capacitor can hold a charge after the power is off. Mop and sign a wet kitchen floor before you start working on it — the slip risk is the immediate hazard, not the appliance. Never clear a drain with a metal probe or a heat gun. Do not move a loaded cabinet on castors alone.
When to call a technician
Call when the drain line is clear and correctly fallen, the gasket seals, and water still collects inside the cabinet — the internal trough or the evaporator drain is then the answer. Call a plumber instead if the waste point itself backs up when you flush the line. Call urgently if the cabinet is also failing to hold temperature while leaking, because that points at a defrost fault and stock is at risk.
Nearest pages of this class
What this page does not cover
This page is written for the brand and the appliance class, not for one family or model line. Where a family- or model-specific page exists for your unit, that page is the more specific answer and you should start there. Deliberately absent: drain line diameters and fall requirements, trap dimensions, gasket part identifiers and defrost timings, all of which differ between the upright, under-counter and prep-counter families and by installation.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
