If temperatures drop below freezing during winter where you store your RV – even for just a couple of hours overnight, then your toilet system needs attention to prevent major problems. When water freezes, it expands by about 9% by volume in the water line, creating extreme pressures within the line.

For example, if the temperatures are expected to fall below freezing (32°F/0°C) for a few hours, then the toilet’s water valve needs to be treated with antifreeze. Never use automotive-type antifreeze that contains ethylene glycol in freshwater systems. Only nontoxic antifreeze with propylene glycol that is designated for potable water systems is recommended.

For gravity-flush toilets, the first step is to empty the freshwater tank. Pour antifreeze in the potable water tank according to instructions from antifreeze manufacturer. Then flush the toilet until antifreeze is flowing completely through the toilet. Never leave water in the bowl that may freeze and crack the ceramic bowl.

Paying attention to the critical areas of your toilet system that are vulnerable to cold temperatures will pay dividends when spring comes and it’s time to get back on the road.