A system's filtered water must be ____ Nephelometric Turbidity Units (NTU) or less in at least _____% of the measurements taken each month.

For a water system to ensure the quality of its filtered water, it is crucial that the turbidity levels remain low, as high turbidity can indicate a presence of pathogens and other contaminants that can compromise water safety. The standard requirement is that the filtered water must maintain a turbidity level of 0.3 NTU or less in at least 95% of the measurements taken during each month. This threshold is significant because maintaining turbidity at or below this level indicates effective filtration processes and helps in minimizing health risks to users.

Turbidity is measured in Nephelometric Turbidity Units (NTU), and keeping it under 0.3 NTU demonstrates compliance with regulatory standards aimed at protecting public health. The stipulation regarding 95% of the measurements reinforces the expectation of consistent performance rather than occasional compliance. This means that most of the time, the water should be clear to assure the users of its safety and quality.

By adhering to these parameters, a water system can not only demonstrate compliance with health regulations but also ensure that it is providing safe drinking water to the community.