After the above dates, consult the latest edition of 40 CFR 141. Coliform Bacteria 1. A public water system must demonstrate compliance with the MCL for total colliform each month it is required to monitor. MCL violations must be reported to the State no later than the and of the next business day after the system learns of the violation. Each public water system must sample according to a written sample sitting plan.
Plans are subject to State review and revision.
The State must establish a process which assures the adequacy of the sample sitting plan for each system. At least one must be upstream and another downstream. If a total coliform-positive sample is at the end of the distribution system or one away from the end of the distribution system, the State may waive the requirement to collect at least one repeat sample upstream of the original sampling site. Monthly monitoring requirements are based on populations served. Invalidation of Total Coliform Positive Samples a.