Standing water over a period of time becomes exposed to natural elements. If you're not using a bacteria killing solution, you may notice with frequent cold plunges in the same water, a film, murkiness or cloudiness starting to develop.
Questions on bacteria and hygiene come to mind especially within cold water. Can bacteria grow in cold water? The answer is yes. Bacteria can still grow in water as cold as 40°F, although the growth rate is likely to be significantly slower compared to warmer temperatures. Many bacteria are mesophilic, meaning they prefer moderate temperatures for optimal growth, and their growth is generally slowed down in cooler conditions.
In cold water, some psychrophilic bacteria that are adapted to lower temperatures may still be able to grow, albeit at a slower pace. However, not all bacteria are psychrophilic, and some may enter a dormant state or have reduced metabolic activity in colder environments.
It's important to note that while cold temperatures can inhibit bacterial growth, they may not completely prevent it. Proper safety and hygiene practices even in extreme temperature cold plunging, such as UV light or Ozone sanitation, can help minimize the risk of bacterial contamination.