What reason makes spas more prone to bacteria compared to pools?

Spas are more prone to bacteria compared to pools primarily due to the smaller amount of water they contain. This limited volume of water leads to a more concentrated environment for contaminants, making it easier for bacteria to proliferate. In smaller bodies of water, the effects of swimmers' introduction of organic material, sweat, and other pollutants are magnified, resulting in a higher likelihood of bacterial growth if not managed properly.

Additionally, the higher water temperature typical of spas enhances bacterial proliferation, as many pathogens thrive in warm environments. While factors such as cleaning frequency and water chemistry also play roles in overall water quality, the smaller water volume is a significant factor in the development of unsanitary conditions in spa environments.