(1) The performance level of an existing building is reduced where the existing building is extended or subject to material alteration or repair and a sewage system serving the existing building is adversely affected by the extension, alteration or repair of the existing building.
(2) Except as provided in Sentence (3), the performance level of an existing building is reduced where proposed construction will increase the occupant load of an existing building, and the new occupant load will result in the total daily design sanitary sewage flow of the building, calculated in accordance with Article 8.2.1.3., exceeding the capacity of any component of a sewage system serving the building.
(3) The performance level of an existing dwelling unit is reduced where proposed construction that,
(a) increases the number of bedrooms in the dwelling unit,
(b) exceeds 15% of the finished area of the dwelling unit, or
(c) adds new plumbing fixtures to the dwelling unit,
will result in the total daily design sanitary sewage flow of the dwelling unit, calculated in accordance with Article 8.2.1.3., exceeding the capacity of any component of a sewage system serving the dwelling unit.
(4) The performance level of an existing building is reduced where proposed construction will result in the change of a major occupancy of all or part of the existing building to another major occupancy and,
(a) the total daily design sanitary sewage flow of the proposed major occupancy, calculated in accordance with Article 8.2.1.3., exceeds the capacity of any component of a sewage system serving the building, or
(b) the type or amount of sanitary sewage which will, under the proposed major occupancy, be discharged to a sewage system serving the building, is prohibited by Article 8.1.3.1.