In all use districts, no dwelling shall hereafter be erected or altered for a one-family dwelling unless provision shall be made therein for not less than 1,000 square feet of habitable floor area; provided, however, that an area of not less than 800 square feet may be provided for within the exterior of the foundation wall at ground level.

Where multiple-family dwellings are allowed, no dwelling shall hereafter be erected or altered for an apartment house unless provisions shall be made therein for not less than 750 square feet of habitable floor area for each apartment unit.

The foregoing provisions of Article V shall be applicable to the dwelling quarters of domestic employees within an accessory building, as permitted by this chapter.