The short answer
A leak from the MCD family is almost always the defrost drain or the water supply, and telling them apart takes one observation: where the water is. On this platform the drain blocks before anything else does, which is why it leads this ranking.
What you observe
- Water pooling under the crisper drawers — The classic blocked defrost drain: melt water has nowhere to go and backs into the cabinet.
- A sheet of ice on the floor of the compartment — Same fault caught later, once the pooled water has frozen.
- Water on the floor at the front — The cabinet floor slopes forward, so a rear leak arrives at the front.
- Damp only at the back of the machine — Supply-side: the inlet connection or the line, and it will be wet when the unit is idle.
- NEAR MISS - condensation on the outside of the doors — That is humidity and seal performance, not a leak.
Causes, most likely first on MCD
- Blocked defrost drain — Ranked first on the MCD family: a compact cabinet has a very short drain that a single piece of debris can close completely. The order below follows the air path rather than the refrigeration circuit, which is a family property and not a model one. What moves against the brand-generic order is lower down: door seals and condensation sits above drain pan cracked or displaced here, because the family spans several sizes on one platform and it is the shared parts that wear.
- Water supply connection or line — Second: a small unit is moved more often than a built-in, and the line is strained every time.
- Door seals and condensation — Third: a glass door on this class of unit condenses readily once the seal has taken a set.
- Drain pan cracked or displaced — Fourth: the pan is the end of the drain path and is disturbed whenever the unit is moved, which makes a recent move the thing to ask about.
- Ice maker fill valve or its tubing — Last: last, and many units in this class have no module at all.
Check in this order, and why
- Empty the compartment and find the drain opening — It is the likeliest cause and it is visible once the shelves are out.
- Check the cabinet is level and tilted very slightly back — A cabinet leaning forward sends melt water towards the door instead of the drain.
- Pull the unit out and look at the connection and the pan — Do this with the cabinet idle: supply leaks are wet when nothing is running.
- Test the seals with a sheet of paper around each door — Last, because it explains condensation rather than standing water.
Before you open anything
Safety
Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Shut the water supply at the stop tap before touching any fill line, and treat the sealed system as off limits: refrigerant work is licensed work.
When to call a technician
Call when the drain keeps blocking after being cleared, because that usually means the drain heater or the defrost circuit is at fault rather than the channel itself.
Other MCD pages
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
