What should prompt cleaning of storage facilities according to water quality sampling?

Cleaning of storage facilities should be prompted by increasing NTUs (Nephelometric Turbidity Units) as it indicates a rise in the turbidity of water. Turbidity is an important water quality indicator; it represents the cloudiness or haziness caused by large numbers of individual particles, which can include sediments, algae, and microorganisms. When turbidity increases, it suggests that the water may be contaminated, which can directly affect the safety and quality of drinking water.

Increased turbidity can inhibit the effectiveness of disinfection processes and could lead to issues with taste, odor, and the presence of harmful pathogens if not addressed. Regular monitoring of NTUs helps ensure that water remains clear and the storage facilities are clean and free from contaminants. Thus, a rise in NTUs serves as a critical signal that cleaning and maintenance are necessary to maintain water quality standards.