Pink water

Pink water in an RV refers to water that has had ‘pink’ antifreeze added to it. This is a common practice in cold climates to prevent the RV’s internal plumbing pipes and tubing from freezing and potentially bursting. The antifreeze used for this purpose is usually a mixture of propylene glycol and water. A typical commercial blend that can withstand temperatures as low as -50°F (-46°C) consists of 40% propylene glycol and 60% water.

The reason it’s colored pink is to indicate that it’s non-toxic, which is an important distinction. Regular antifreeze, which is a mix of ethylene glycol and water and used in engines, is colored green or blue. This coloring is a warning that it is toxic and should be handled with care. In contrast, the pink antifreeze used in RV plumbing systems is safer for use in a living environment.