Freeze season starts earlier than you think
Every spring we take in containers destroyed by one bad night in October. The calendar is not the trigger — the dew point is, and there is a simple rule that saves most of them.
- Sheet
- 52
- Revision
- 2026-10
- Scale
- 1:1
- Drawn at
- Peoria IL
Water expands about nine percent when it freezes. A polyethylene bottle does not expand at all, and a valve body is the least forgiving part of the whole assembly. Those three facts are the entire subject.
The rule we use in the yard is simpler than any forecast: when the overnight dew point is within four degrees of freezing for two nights running, anything that holds water gets drained. Air temperature lies to you — a clear, still night radiates heat off a dark tote faster than the air cools, and we have pulled ice out of sumps on mornings that never officially dropped below 34.
| Component | Freeze tolerance | What happens | Recovery |
|---|---|---|---|
| Outlet valve body | Very poor | Cracks at the seat or the flange | Replace, $14–24 |
| Sump of the bottle | Poor when full | Bulges, then permanently deforms | Rebottle, $74–96 |
| Bottle wall | Fair | Stress whitening at corners | Grade drop |
| EPDM gasket | Fair | Compression set | Gasket kit, $6–11 |
| Steel cage | Good | Fine unless the bottle pushed it out of square | Jig if needed |
| Composite pallet | Good | Ice-jacking under the runners | Usually nothing |
The order things freeze in
- The valve body — small volume, metal or thin polypropylene, exposed on all sides. This is the part you lose first and the one people never drain.
- The sump, because it is the deepest, stillest water in the container and it sits closest to the cold ground.
- Any horizontal run of hose or manifold, which is why blowing the lines matters as much as draining the tote.
- The main body, last, and by then the damage is already done further down.
What we do in the yard in late October
Drain below the sump line
Valve open, cap off, container tipped slightly. A container that is 'basically empty' still has a gallon in the sump and that gallon is what costs you a valve.
Blow the lines
Compressed air through every manifold, header and hose run. Gravity does not reach a horizontal line and hope is not a procedure.
Single-tier anything undrained
Frozen contents plus a double stack is how cages fail catastrophically rather than expensively.
Valves out of the wind
Turn stacks so the outlets face away from prevailing wind if they must stay outside. It is worth two or three degrees.
If you genuinely need winter capacity, insulate and heat — closed-cell wraps buy a few degrees, and a thermostatic inline heater or heat-trace with a controller buys the season. What does not work is leaving a full container outside and hoping for a mild February, which is the single most common story behind the rebottling work we do in March.
The spring arrivals this rule would have prevented
- Forty-one containers in March 2023 with bulged sumps, every one of them stored full outdoors.
- Nineteen cracked valve bodies, all of them cheap to fix and all of them a container out of service for a month because nobody had a spare.
- Six caved tops from a different cause — vents closed during a cold discharge, which pulls a vacuum as the contents contract.
- Two cages pushed so far out of square by a frozen bottle that the frame itself had to be jigged.
Already have a cracked bottle?
Do not scrap the container. The cage, pallet and often the valve are fine, which makes it a rebottle at about half the price of replacement.