The use of Ufer grounds in residential slab-on-ground foundations here is prevalent and allowed by the NEC.
E3508.1.2 Concrete-encased electrode. An electrode
encased by at least 2 inches (51 mm)of concrete, located within
and near the bottom of a concrete foundation or footing that is
in direct contact with the earth, consisting of at least 20 feet
(6096 mm) of one or more bare or zinc-galvanized or other
electrically conductive coated steel reinforcing bars or rods of
not less than 1/2 inch (12.7 mm) diameter, or consisting of at
least 20 feet (6096 mm) of bare copper conductor not smaller
than 4 AWG shall be considered as a grounding electrode.
Reinforcing bars shall be permitted to be bonded together by
the usual steel tie wires or other effective means.
My question concerns the wording "coated steel". I have not yet seen anything used other than regular uncoated reinforcing steel bars. Is this a code violation? And, what coatings are allowed?