How soon must the state regulatory body be notified of unusual or extraordinary discharges?

The requirement to notify the state regulatory body of unusual or extraordinary discharges within 24 hours aligns with the need for prompt communication to ensure compliance with environmental regulations and safeguard public health and safety. Reporting within this time frame allows for timely assessment and mitigation measures to be put in place, which is crucial when dealing with discharges that may cause environmental harm or violate water quality standards.

This timeframe is established by regulatory guidelines to balance the operational realities of wastewater treatment facilities with the urgency of potential impacts associated with abnormal discharge events. Failure to notify promptly might hinder the state's ability to respond effectively, potentially leading to violations and environmental damage.

The other choices represent lengths of time that are generally considered too long for immediate reporting obligations in such sensitive situations.