Pathogens in unhealthy pool water are microorganisms that cause illness. The range of pool water pathogens have been well documented by State Health Guidelines for public pool water quality. Unhealthy pool water looks clean because the pathogens are not visible to the naked eye.
Chlorine used in pool water, in an effort to kill pathogens, creates chlorine by-products. What is mistakenly thought to be a strong smell of chlorine around pools is not chlorine but chlorine by-products. Chlorine in clean water doesn’t smell.
Unfortunately, the health risks associated with chlorine by-products have not been well documented in State Health Guidelines for public pool water quality.