Which feature is not part of a properly designed septic system?

A properly designed septic system typically includes critical components that ensure effective waste treatment and disposal. Among the options provided, the idea that all systems should have a backup generator is not standard practice for septic systems.

Septic systems primarily consist of a tank and an absorption field or drain field, which are designed to treat wastewater efficiently through natural processes. The absorption field is crucial for filtering the effluent before it reaches the groundwater, while a lagoon system can serve as an alternative method for wastewater treatment, particularly in larger or rural settings.

Having a standby pump can be beneficial in certain situations, particularly in areas prone to flooding or where gravity flow cannot be relied upon. However, a backup generator is not a necessary feature for the effective operation of a septic system. Most septic systems are designed to function without electric components under normal circumstances, relying instead on gravity and the natural flow of wastewater. Therefore, while a backup generator might be useful in some contexts, it is not a requisite feature of a well-designed septic system.