Which of the following is a key requirement for an HTSS's pumping service?

The key requirement for an HTSS's pumping service is that service frequency should be specified in the permit. This is crucial because the permit outlines the conditions under which the septic system can operate safely and effectively, ensuring compliance with local regulations and standards. It helps to manage the risks associated with system overload, environmental contamination, and health hazards by setting a routine pumping schedule that aligns with the system's capacity and usage.

Specifying the service frequency in the permit also ensures accountability and helps maintain the system's performance over time. Consistent maintenance is essential for preventing failures, which could lead to costly repairs or environmental damage. Proper documentation of service frequency contributes to the longevity and reliability of the septic system, aligning with public health and safety guidelines.

The other options do not appropriately reflect the critical nature of regular, specified maintenance for septic systems. For instance, irregular pumping may lead to system failure, and assuming that pumping is unnecessary if the tank isn't full overlooks the fact that sludge and scum build-up still occurs over time. Additionally, while some service providers are qualified to perform pumping services, not all can meet the regulatory standards required for HTSS systems, thus emphasizing the importance of using certified professionals.