How many coliform positive samples can be collected in a month for water systems that collect less than 40 samples?

The correct answer is that only one coliform positive sample can be collected in a month for water systems that collect less than 40 samples. In water quality monitoring, particularly for total coliform bacteria, regulatory guidelines set thresholds to ensure safe drinking water. For systems that collect fewer than 40 samples a month, having more than one positive sample indicates a potential risk and thus triggers further investigation and remedial actions.

This limit helps to maintain water safety and quality, reducing the likelihood of broader contamination issues. The standard supports the necessity for utilities to monitor closely and respond effectively to maintain public health standards. Therefore, while detecting coliforms in drinking water is serious and concerning, the allowable number of positive samples is quite restrictive to encourage prompt action in case of contamination risk.