With the principle of constructing, connecting and activating the sewerages within the same lane, some residences in the same lane without construction space of a width of 1.5m (75cm at each side) preserved or underground barriers not removed will reversely affect the expected schedule. Sometimes, the root cause of delay is replacement or removal of gas lines or tap-water lines. (For any question, please dial the phone number of 25973183, Ext. 204 or Citizen Hot Line, 1999 (or 02-27208889 for areas beyond Taipei City).