Sanitation – Trap that disconnects a house drain from the public sewer What is the name of the trap installed to isolate the house drainage system from the street sewer, usually inside an intercepting chamber near the property boundary?

Introduction / Context:
House drainage must be protected from foul gases and backflow from the public sewer. A dedicated trap is provided near the property boundary inside a manhole to disconnect the house drain from the municipal sewer line.

Given Data / Assumptions:

• Conventional building drainage per common practice.
• Device located at the last manhole before connecting to the public sewer.
• Purpose: block sewer gases and provide a cleaning eye.

Concept / Approach:
An intercepting trap (often called a master trap colloquially) provides a deep water seal at the junction to the public sewer. The manhole is termed an intercepting or inspection chamber, but the trap itself is specifically the intercepting trap.

Step-by-Step Solution:
Identify component whose function is to disconnect: the trap element.Name of the trap: Intercepting trap.Associated structures (manhole/chamber) house the trap but are not the trap.

Verification / Alternative check:
Standard sanitation layouts show a deep-seal intercepting trap just upstream of the public sewer connection inside the intercepting chamber.

Why Other Options Are Wrong:

• Master trap: colloquial synonym used inconsistently; the standard term is “intercepting trap”.
• Interception manhole / Intercepting chamber: these are structures, not the trap device.
• All of the above: mixes device name with housing structures; not precise.

Common Pitfalls:
Confusing the chamber/manhole with the trap inside, or treating a colloquial name as a formal specification term.

Final Answer:
Intercepting trap