Where must records for the operation and maintenance of wastewater treatment plants be maintained according to regulations?

Records for the operation and maintenance of wastewater treatment plants must be maintained in compliance with the regulations outlined in the Code of Massachusetts Regulations, specifically 314 CMR 12.00. This regulation provides a comprehensive framework that addresses the operational requirements, record-keeping obligations, and overall management of wastewater treatment facilities. By adhering to these regulations, operators ensure that they are in line with state standards for environmental protection and public health.

Maintaining records as specified in these regulations assists in establishing accountability for operational practices, demonstrates compliance during inspections, and supports efficient management of the treatment processes. It's essential for operators to familiarize themselves with the regulations to fully understand the scope of documentation required, which includes operational logs, maintenance activities, and compliance reporting.

Other options that suggest maintaining records solely in a digital format or at local city halls do not reflect the legal requirements set forth by the state regulations. While digital records are beneficial for accessibility and organization, the requirement for maintaining records is specifically tied to the regulations, which dictate the content and manner of record-keeping. Therefore, option B accurately captures the regulatory foundation that governs record maintenance for wastewater treatment facilities.