Find the highest wet point
Water runs downhill and pools at the lowest spot, which is almost never where it came from. The useful question is where the water is highest, not where it is deepest. Dry the floor completely, then come back in an hour and look at where it has started again.
The four sources
1. Drain overflow or leak
Water appears directly under or behind the evaporator, usually in a consistent spot. Causes: the drain line is blocked, the pan has rusted or cracked, or the pan has shifted on its mounts so water runs off the edge rather than to the outlet. Look for mineral staining or a rust trail, which maps the path water has been taking for months.
2. Condensation inside the box
Water appears generally rather than in one place, often with visible beading on walls, shelving or the ceiling. This is humidity, which means air is getting in. In a cooler, warm air hitting cold surfaces simply condenses rather than freezing, so the symptom is wet rather than icy — but the cause is identical to the freezer version of this problem.
3. Water entering from outside
Appears at the door threshold and runs inward. Kitchen floors get hosed, mopped and spilled on, and if the door sweep is missing or the threshold has lifted, that water goes straight into the box. Easy to confirm: does it appear right after the floor crew have been in?
4. Product and packaging
Worth mentioning because it accounts for a fair share of calls. Produce delivered wet, ice melting from a seafood delivery, condensation off cases brought in warm. Not a refrigeration fault, but genuinely the answer sometimes, and we would rather say so than invent something.
Why a cooler shows water where a freezer shows ice
The mechanism is the same — moisture arriving and condensing on cold surfaces — but above freezing it stays liquid. That makes it less visually alarming and more immediately problematic, because water on a floor is a sanitation and safety issue the moment it appears, whereas ice announces itself slowly.
It also means a cooler with a water problem and a freezer with an ice problem in the same kitchen often share a single root cause: a back door propped open in summer, a failing air handling setup, or a dish area pushing steam into the storage area.
The slip risk is the urgent part
A wet, smooth floor in a cold room where people carry heavy cases with both hands is a serious injury setting. Most operators we deal with treat the compliance side as the pressure point, but the injury side is the one that actually ends up costing real money. If there is standing water, a mat is a stopgap and not a solution — mats on a wet cooler floor hold the water and grow things.
What we check
- Drain line clear end to end, not just at the outlet.
- Drain pan integrity, including the back edge and the seams, which is where they fail.
- Pan level and alignment on its mounts.
- Door seal along its full perimeter and the condition of the sweep.
- Box humidity, and where the air is getting in if it is high.
- Whether the floor itself has settled, creating a low point that holds water that would otherwise drain to the threshold.
On a cooler this is often a short visit with a cheap fix — a sweep, a gasket, a cleared drain. It is one of the faults most worth calling about early, because the repair is small and the consequences of leaving it are not.
Questions we get asked
Is standing water in a walk-in a health code violation?
It is a recognised sanitation problem and an inspector will cite it. Standing water on a cooler floor promotes bacterial growth, attracts pests, and creates a slip hazard. It is one of the easier things for an inspector to see immediately on entering the box.
The water is only there in summer. Why?
Humidity. Warm humid air entering the box condenses on every cold surface, and in a Boston July there is a lot more moisture in that air than in February. Summer-only water almost always means infiltration rather than a drain fault.
Why would the drain pan rust through?
Age and chemistry. Pans sit permanently wet, and cleaning chemicals, food acids and salt accelerate corrosion. A pan that has rusted at the seam leaks slowly and invisibly because the water runs down the back of the coil rather than out the front.