Hunting camp: will a standard porta potty's holding tank crack if it freezes solid in October?

Yes, a standard portable toilet holding tank can crack if it freezes solid. The plastic tank expands when waste water freezes, and without antifreeze, this expansion can cause splits or fractures, leading to leaks and costly repairs. For your Montana hunting camp with six people using it over weekends in October, you should ask the rental company to add a non-toxic antifreeze solution during their service visits. This is standard winterization practice to prevent freezing damage. Since the rental company services every other week and temperatures drop below freezing, the antifreeze is necessary to protect the unit. Ensure the unit is placed on level ground with good truck access for service. Do not try to add anything yourself, as it might void the rental agreement or cause issues with waste disposal regulations. Communicate clearly with your provider about the cold weather conditions to avoid problems.