(a) Each plastic service line outside a building must be installed below ground level, except that:
(1) it may be installed in accordance with section 255.321(l) of this Part;and
(2) it may terminate above ground level and outside the building if:
(i) the above ground part of the plastic service line is protected against deterioration and external damage.
(ii) the plastic service line is not used to support external loads; and
(iii) The riser portion of the service line meets the design requirements of ยง255.204.
(b) Each plastic service line inside a building must be protected against external damage and must not be exposed.