The short answer
A built-in cabinet hides its drain path behind furniture, so the first thing to establish is whether the water is defrost water that could not get out. Ranked first on this platform: A blocked defrost drain. The checks below follow that ranking, and the first of them need no tools and no panel removed.
What you observe
- Water under the crisper drawers, and a wet patch at the front of the floor — Water inside before it is outside means it started in the cabinet, not at a fitting.
- Water at the door line, with condensation or frost around the same part of the seal — The wet patch marks where the air is coming in.
- The leak started within a day or two of a filter change — The date of the change is the strongest single piece of evidence on the whole page.
- NEAR MISS — the outside of the cabinet is wet rather than the floor under it — That is condensation on the shell, which points at a door seal or at humidity rather than at a drain or a supply line.
Causes, most likely first on this platform
- A blocked defrost drain — Every cabinet that defrosts itself has to send the meltwater somewhere, and it all goes through one small drain hole into a pan underneath. It ranks first on this platform because the drain is a single small hole at the back of the compartment floor, and once it blocks the water backs up under the drawers and then over the front lip — which in a built-in installation means it runs into the joinery before anyone sees it.
- Humid air entering past a door seal — A seal that is not sealing lets room air in continuously. It ranks second here because the appliance is built into furniture, so the housing, the clearances and the alignment the fitter left behind are part of every fault it produces.
- The filter housing — The filter head carries pressurised water and takes a quarter-turn twist each time a filter is changed. It comes third in the order — a genuine cause here, behind the ones above it on frequency alone.
Check in this order, and why
- Take the drawers out and look for standing water in the floor of the compartment — It places the leak inside the cabinet in one look and costs nothing. It leads because it tests the top-ranked cause.
- Run a slip of paper round the door seal and note where it pulls out freely — It maps the failure round the whole door in a couple of minutes. Tests the second-ranked cause.
- Take the filter out, look at the O-rings, and refit it firmly to its stop — It costs nothing and it is the first thing to do when the timing fits. Tests the third-ranked cause.
What an owner can safely check
- Clear the drain hole from inside with warm water and a soft flexible line — Warm water first; anything stiff enough to punch through ice is stiff enough to puncture the tray.
Tools: warm water, turkey basterAbout 30 min
- Wash the gasket with warm soapy water, dry it, and repeat the paper test — A gasket glued open with spilled food often reseals once it is properly clean.
Tools: clothAbout 20 min
- STOP before anything behind a fixed panel, and note what each check showed — Everything past this line is measured rather than looked at, and measuring it safely needs the power off and a meter.
Before you start tracing it
Safety
Unplug the appliance or switch off its breaker before removing any panel or reaching into the base — a capacitor can hold a charge after the power is off, and water plus a live compartment is the one combination to take seriously.
When to call a technician
Call once the water is coming from behind a sealed panel, from the sealed system, or from a drain that will not clear from the cabinet side.
Nearest pages of this class
What this page does not cover
This page is written for the Miele refrigerator as a class, not for one family or one model line. Where a family- or model-specific page exists for your unit, that page is the more specific answer and the one to read first. Deliberately not here: part numbers, wiring colours and disassembly order, which differ by family.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
