Unfortunately, this isn't always the case. 'A pool may be free of debris, and the water may look crystal clear, but unpleasant scenarios can come about when swimming in water that’s not properly balanced,' warns Clay Spann of Leslie's. Imbalanced pool water can encourage the growth of disease-causing microorganisms, and pool water must be disinfected to rid it of these harmful pathogens, he says.
'Without testing to look at the water chemistry and ensure proper chlorine levels in the pool, you just don’t know if the pool water is safe and sanitized. You have to test regularly.'