What type of receptacle receives sanitary or storm waste located below the normal grade level of the gravity system?

What type of receptacle receives sanitary or storm waste located below the normal grade level of the gravity system?

• A. Trench
• B. Septic Tank
• C. Infiltration Pit
• D. Sump

Answer: (D)

When waste collects below the level of the gravity sewer, you need a pumping-receiving receptacle. A sump is exactly that: a below‑grade basin that receives sanitary or storm water and is designed to be pumped up to the gravity system. This arrangement is necessary because gravity alone can’t move liquid from a point lower than the sewer line, so the sump stores the liquid and the pump lifts it to elevation so it can continue by gravity to the main line. The other options aren’t meant for this purpose: a trench is just an excavation for drainage, not a storage receptacle; a septic tank is an on-site treatment vessel for wastewater, not a below-grade pumping point for a building’s gravity system; and an infiltration pit is used to absorb water into the soil, not to receive and discharge pumped waste to the sewer.

When waste collects below the level of the gravity sewer, you need a pumping-receiving receptacle. A sump is exactly that: a below‑grade basin that receives sanitary or storm water and is designed to be pumped up to the gravity system. This arrangement is necessary because gravity alone can’t move liquid from a point lower than the sewer line, so the sump stores the liquid and the pump lifts it to elevation so it can continue by gravity to the main line.

The other options aren’t meant for this purpose: a trench is just an excavation for drainage, not a storage receptacle; a septic tank is an on-site treatment vessel for wastewater, not a below-grade pumping point for a building’s gravity system; and an infiltration pit is used to absorb water into the soil, not to receive and discharge pumped waste to the sewer.