Restroom Trailer Frozen or Not Flushing in Cold Weather
If a restroom trailer stops flushing or the sinks run dry after a freezing night, the fresh-water line or tank has most likely frozen. Close the trailer to guests, keep its power on, and call the rental company before anyone tries to thaw lines.
Most rental companies offer a heat package for winter. Stahla's published 2026 rate table lists a Heat Lock add-on at $499 per event, which is far less than a cracked line or a cancelled event.
If this is unsafe or getting worse right now, don't wait — send an emergency request and it's flagged for priority routing to an independent local pro.
What to do in the first 5 minutes
- Lock the trailer or post a sign so guests stop flushing into a dry system.
- Confirm the trailer is still plugged in or the generator is running; heaters and heat tape need power.
- Call the rental company's service line and describe what stopped working (flush, sinks, or both).
- Open nearby portable units or a backup trailer if the event is underway.
- Ask for a heat package or tank heater on the rest of the rental.
Do not do this
- Do not use open flames or torches on lines or tanks.
- Do not run extension cords through standing water or snow to power space heaters.
What's likely going on
Fresh-water hose or inlet frozen
Exposed supply hoses freeze first. The rental crew can swap to a heated hose or switch to the onboard tank.
Power interrupted overnight
If the generator ran out of fuel or a breaker tripped, the trailer's heat tape and heaters stopped.
No winter package on the order
Summer-spec trailers are not built for sustained freezing nights without added heat.
What it typically costs
Stahla's 2026 table lists the Heat Lock add-on at $499 per event, $599 per week and $699 per 28 days (published vendor rate card).
Frequently Asked Questions
Can I pour hot water into the tank?
Ask the rental company first. Some tanks and pumps can be damaged, and the rental agreement may make you responsible.
Will the rental company come out the same day?
Most offer service calls; the response time depends on the contract and distance, so check it when booking a winter rental.
Should I add the heat package for a spring event?
If overnight lows can drop below freezing, yes. Stahla lists the Heat Lock add-on at $499 per event—less than a cancelled event or a cracked line.
The service that handles this
Guidance only — independent local providers assess and price their own work. Last reviewed: October 16, 2026.
Sources for the cost figures
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