The house trap is a deep seal trap placed inside the foundation wall, and intersects the house drain and house sewer. The trap is placed at this point for a number of reasons: first, to keep sewer gases from entering the pipes in the house; second, this location is where the house drain ends. This trap should have two clean-outs, one on each side of the seal. The clean-outs should be of extra heavy cast-iron body with a heavy brass screw cap. The cap should have a square nut for a wrench to tighten or unscrew the cap. This cap should be brought up flush with the floor. When a house trap is being set, it is necessary to set it perfectly level, otherwise the seal of the trap is weakened and sewer gases can enter.

Sometimes the trap is located on the house sewer just outside of the foundation wall. In this case, a pit should be built large enough for a workman to get down to it to clean it out when necessary.

A mason's trap was formerly used to a considerable extent, but is very poor practice to use today on modern work. This trap was built square of brick with a center partition. The brick soon became foul and the trap would be better termed a small cesspool than a trap.

Points To Remember About House Traps

  1. First, should be a running trap.
  2. Second, two clean-outs.
  3. Third, deep seal, at least 2 inches.
  4. Fourth, set level.
  5. Fifth, set inside foundation wall.
  6. Sixth, accessible at all times.
  7. Seventh, same size as house drain.
  8. Eighth, fresh air should connect with it.