Which statement correctly describes the desired flow from the house sewer to the septic tank?

The statement that the flow from the house sewer to the septic tank must be at least 3 inches higher than the tank outlet is correct because it ensures that gravity is utilized to facilitate a proper flow of wastewater from the house into the septic tank. This elevation differential is crucial for maintaining an uninterrupted and efficient flow, preventing any potential backflow or blockages that could occur if the outlet were at the same level or higher than the inlet from the house.

Maintaining this slope ensures that wastewater will easily move into the tank and helps to keep the system functioning as intended. A consistent downward flow not only supports effective waste management but also aids in the separation of solids and liquids within the septic tank.

The other choices indicate various misconceptions about the installation angle and flow requirements. While it is true that a slight fall is necessary to facilitate drainage, this specific requirement does not mandate a level flow or invalid slope, as indicated in other options.